248 pubblicazioni classificate nel seguente modo:

Distance properties of punctured simplex codes and design of high-rate PRC-LDPC codes for complexity-constrained applications
IEEE TRANSACTIONS ON INFORMATION THEORY
Autore/i: Battaglioni, M.; Baldi, M.; Chiaraluce, F.; Cancellieri, G.
Classificazione: 1 Contributo su Rivista
Abstract: Cyclic simplex codes are usually deemed as impractical because of their extremely low rate and large codeword length for practical values of the code dimension. To address these limitations, researchers have resorted to punctured simplex codes, focusing on primitive polynomials and employing statistical analyses to investigate their properties. This paper delves deeper into the properties of punctured binary simplex codes, also focusing on the recently introduced family of Primitive Rate-Compatible Low-Density Parity-Check (PRC-LDPC) codes. We study the average behavior of punctured simplex codes in terms of minimum distance properties. Furthermore, our results highlight the potential of high-rate PRC-LDPC codes to reach or even surpass the performance of state-of-the-art code families. We show how to design good codes by applying puncturing and shortening operations to cyclic simplex codes, also considering complexity-constrained scenarios.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/350852

Impact of Error-Correcting Code Performance on Telecommand Rejection in Ground-to-Space Communications
2025 33rd International Conference on Software, Telecommunications and Computer Networks, SoftCOM 2025
Autore/i: Giuliani, R.; Maturo, N.; Rovelli, D.; Battaglioni, M.; Baldi, M.; Chiaraluce, F.
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In space missions, particularly deep space ones, one of the key needs is to establish a link with the satellite, even during the safe and survival modes, in order to maintain the capabilities to send TeleCommands (TCs) to the satellite and to receive Housekeeping TeleMetries (TMs) from the satellite. In current deep space missions, such as BepiColombo, TCs are typically encoded by the Bose-Chaudhuri-Hocquenghem (BCH) code specified in the Consultative Committee for Space Data Systems (CCSDS). However, for upcoming deep space missions still in the development phase, short Low-Density Parity-Check (LDPC) codes (also standardized by the CCSDS), with length 128 or 512 bits and coding rate 1/ 2, are being considered alongside the BCH code. Since the goal is to introduce minimal changes to the existing ground systems, it is necessary to evaluate system performance when the LDPC codes are used in place of the BCH code currently implemented. This paper first focuses on the analysis of the application of a (128, 64) LDPC code in the current configuration. Then, we provide an overview of alternative configurations and compare the performance of the system when using the (63, 56) BCH code, the (128, 64) LDPC code and the (512, 256) LDPC code.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/350413

BF-Max: an Efficient Bit Flipping Decoder with Predictable Decoding Failure Rate
IEEE International Symposium on Information Theory - Proceedings
Autore/i: Baldelli, Alessio; Baldi, Marco; Chiaraluce, Franco; Santini, Paolo
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The Bit-Flipping (BF) decoder, thanks to its very low computational complexity, is widely employed in post-quantum cryptographic schemes based on Moderate Density Parity Check codes in which, ultimately, decryption boils down to syndrome decoding. In such a setting, for security concerns, one must guarantee that the Decoding Failure Rate (DFR) is negligible. Such a condition, however, is very difficult to guarantee, because simulations are of little help and the decoder performance is difficult to model theoretically. In this paper, we introduce a new version of the BF decoder, that we call BF-Max, characterized by the fact that in each iteration only one bit (the least reliable) is flipped. When the number of iterations is equal to the number of errors to be corrected, we are able to develop a theoretical characterization of the DFR that tightly matches with numerical simulations. We also show how BF-Max can be implemented efficiently, achieving low complexity and making it inherently constant time. With our modeling, we are able to accurately predict values of DFR that are remarkably lower than those estimated by applying other approaches.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/350412

Data Certification Strategies for Blockchain-based Traceability Systems
Proceedings of the 2025 IEEE International Conference on Blockchain and Cryptocurrency (ICBC)
Autore/i: Zonneveld, Giacomo; Rafaiani, Giulia; Battaglioni, Massimo; Baldi, Marco
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The use of blockchains for data certification and traceability is now well established in both the literature and practical applications. However, while blockchain-based certification of individual data is clear and straightforward, the use of blockchain to certify large amounts of data produced on a nearly continuous basis still poses some challenges. In such a case, in fact, it is first necessary to collect the data in an off-chain buffer, and then to organize it, e.g., via Merkle trees, in order to keep the size and quantity of certification data to be written to the blockchain small. In this paper, we consider a typical system for blockchain-based traceability of a production process, and propose and comparatively analyze some strategies for certifying the data of such a process on blockchain, while maintaining the possibility of verifying their certification in a decentralized way.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/346592

Telecommand Rejection Probability in CCSDS-Compliant LDPC-Coded Space Transmissions with Tail Sequence
IEEE ACCESS
Autore/i: Giuliani, Rebecca; Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco; Maturo, Nicola
Classificazione: 1 Contributo su Rivista
Abstract: According to the Consultative Committee for Space Data Systems (CCSDS) recommendation for TeleCommand (TC) synchronization and coding, the Communications Link Transmission Unit (CLTU) consists of a start sequence, followed by coded data, and a tail sequence, which might be optional depending on the employed coding scheme. With regard to the latter, these transmissions traditionally use a modified Bose–Chaudhuri–Hocquenghem (BCH) code, to which two state-of-the-art Low-Density Parity-Check (LDPC) codes were later added. A low-complexity approach classically used to detect CLTU termination is to choose a non-correctable string as the tail sequence, and then exploit the decoder failure on that sequence as termination detection. This works very well with the BCH code, for which bounded-distance decoders are employed. Instead, when the same approach is employed with LDPC codes and probabilistic belief propagation iterative decoders, the scenario becomes more challenging. In this paper, we study CCSDS-compliant space communications in which LDPC codes are employed, and analyze the TC rejection probability both theoretically and through intensive numerical simulations. Such a performance figure, being the rate at which CLTUs are discarded, should clearly be minimized. Our numerical analysis considers many different choices of the system parameters (e.g., length of the CLTU, decoding algorithm, maximum number of decoding iterations). Particular attention is devoted to the probability of not-acknowledged termination, i.e., the probability that the tail sequence is not recognized.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/338974

Design and Analysis of the Tail Sequence for Short LDPC-Coded Space Communications
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
Autore/i: Battaglioni, Massimo; Andrews, Kenneth; Giuliani, Rebecca; Marinelli, Fabrizio; Chiaraluce, Franco; Baldi, Marco
Classificazione: 1 Contributo su Rivista
Abstract: According to some standards for satellite communications, the transmitted stream is divided into transmission units with variable length, for which detecting the termination is particularly relevant. This is the case of space TeleCommands (TCs), where coded data are usually preceded by a start sequence, and optionally followed by a tail sequence, forming the Communication Link Transmission Unit (CLTU). Regarding the choice of schemes for error correction, the Consultative Committee for Space Data Systems recommendations for TC synchronization and coding suggests to use, among others, two Low-Density Parity-Check (LDPC) codes: one (relatively) long and one short. Adopting the long LDPC code eliminates the need for a tail sequence, as the LDPC decoder always fails when overrunning the end of the CLTU, thus causing the decoding and detection process to stop. This, however, is not true when the short LDPC code is adopted, since its decoding might converge on a codeword even when the decoder input is not a noisy codeword. This makes it necessary to use a tail sequence that causes the decoder to fail regardless of its input. In this paper, we study the features required for such a sequence and propose some methods for its design. Our numerical results, obtained considering various detection approaches for the tail sequence, show that the overall TC rejection probability improves significantly when the proposed tail sequence is employed. Our simulations also show that, for moderate values of the Signal-to-Noise Ratio (SNR), with a properly designed tail sequence it is possible to obtain the same performance in terms of TC rejection probability using decoderbased detection and likelihood ratio test-based detection, with the former approach being less complex than the latter.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/346652

A new path to code-based signatures via identification schemes with restricted errors
ADVANCES IN MATHEMATICS OF COMMUNICATIONS
Autore/i: Baldi, Marco; Battaglioni, Massimo; Chiaraluce, Franco; Horlemann, Anna-Lena; Persichetti, Edoardo; Santini, Paolo; Weger, Violetta
Classificazione: 1 Contributo su Rivista
Abstract: In this paper, we introduce a new variant of the syndrome decoding problem (SDP), called restricted SDP (R-SDP), in which the entries of the solution vector live in a fixed subset of the underlying finite field. We prove the NP-completeness of R-SDP via a reduction from SDP and show how this new problem can be employed in identification schemes. We revisit some concepts of classical coding theory in light of this new setting, provide several bounds such as the Gilbert-Varshamov, the Singleton, and the Plotkin bound, and study the behavior of random codes. Resulting from this initial work, several proposals have arisen; in particular, the code-based digital signature scheme named CROSS, which is currently competing within NIST's additional call for post-quantum digital signatures, is based on R-SDP.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/338732

HQC Beyond the BSC: Towards Error Structure-Aware Decoding
Code-Based Cryptography
Autore/i: Baldi, Marco; Bitzer, Sebastian; Lilla, Nicholas; Santini, Paolo
Editore: Springer Science and Business Media Deutschland GmbH
Classificazione: 2 Contributo in Volume
Abstract: In Hamming Quasi-Cyclic (HQC), one of the finalists in the NIST competition for the standardization of post-quantum cryptography, decryption relies on decoding a noisy codeword through a public error-correcting code. The noise vector has a special form that depends on the secret key (a pair of sparse polynomials). However, the decoder, which is currently employed in HQC, is agnostic to the secret key, operating under the assumption that the error arises from a Binary Symmetric Channel (BSC). In this paper, we demonstrate that this special noise structure can instead be leveraged to develop more powerful decoding strategies. We first study the problem from a coding-theoretic perspective. The current code design, which admits a non-zero decryption failure rate, is close to optimal in the setting of a decoder that is agnostic to the error structure. We show that there are code-decoder pairs with a considerably shorter code length that can guarantee unique decoding by taking the error structure into account. This result is non-constructive, i.e., we do not provide an explicit code construction and it remains open whether efficient decoding is possible. Nevertheless, it highlights the potential that can be tapped by taking the error structure into account. We then argue that, in practice, the matter of decoding in HQC can be related to solving an instance of the noisy syndrome decoding problem, in which the parity-check matrix is constituted by the polynomials in the secret key. We show that, using decoders for Low-Density Parity-Check (LDPC) and Moderate-Density Parity-Check (MDPC) codes, one can significantly reduce the entity of the noise and, de facto, also the Decoding Failure Rate (DFR) of the HQC decoder. This preliminary study leaves some open questions and problems. While it shows that decoding in HQC can be improved, the modeling of the DFR gets more complicated: even for the basic decoder we propose in this paper, we have not been able to devise a reliable DFR model. This is likely due to the fact that the decoder structure resembles the iterative nature of LDPC/MDPC decoders, for which devising a reliable DFR estimation is a well-known difficult problem.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/345073

Machine Learning-Based Tail Sequence Detection in LDPC-Coded Space Transmissions
Proceedings of IEEE Wireless Communications and Networking Conference (WCNC) 2025
Autore/i: Battaglioni, Massimo; Giuliani, Rebecca; Chiaraluce, Franco; Baldi, Marco
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In the context of space communications, as per the recommendation from the Consultative Committee for Space Data Systems regarding TeleCommand synchronization and coding, the Communications Link Transmission Unit is composed of a start sequence, coded data, and a tail sequence, which might be optional depending on the employed error correcting code. The task of detecting the tail sequence must be handled along with that of decoding the codewords containing the transmitted data, and this poses some challenges. In this paper, we propose a machine learning model for recognizing the tail sequence based on the analysis of metrics calculated during decoding, when the transmission is coded with Low-Density Parity-Check (LDPC) codes. The model is trained on data produced by an iterative decoder, commonly used in LDPC decoding, with noisy (random) codewords or the noisy tail sequence as inputs. We report the results of some preliminary experiments showing that this approach is capable of achieving very high levels of accuracy using multiple classifiers.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/343014

Leveraging the Physical Layer to Achieve Practically Feasible Confidentiality and Authentication
Physical‐Layer Security for 6G
Autore/i: Baldi, Marco; Senigagliesi, Linda
Editore: wiley
Classificazione: 2 Contributo in Volume
Abstract: This chapter discusses how the physical layer of wireless communications can be exploited to achieve a reasonable level of security in real systems. Unlike theoretical studies that often make ideal assumptions, such as random coding, continuous modulations, and perfect channel knowledge, we consider conditions that occur in real systems complying with common communication standards. By exploiting appropriate techniques to cope with the non-idealities of such systems, such as all-or-nothing transforms, on-off transmission protocols and machine learning, we show how good performance in terms of confidentiality and authentication at the physical layer can also be achieved in real systems
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/337072

Design and analysis of a family of complexity-constrained LDPC codes
2024 IEEE International Symposium on Information Theory (ISIT): Proceedings
Autore/i: Battaglioni, Massimo; Amagliani, Matteo; Baldi, Marco; Chiaraluce, Franco; Cancellieri, Giovanni
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper we study a special family of Low-Density Parity-Check (LDPC) codes, called Primitive Rate-Compatible (PRC) LDPC codes, obtained by applying puncturing to some properly chosen simplex codes. We investigate their minimum distance properties and give insights on the design of PRC-LDPC codes for use in scenarios where constraints on hardware and software resources require maintaining a low level of complexity. We numerically assess the error rate performance of these codes in such a setting, showing that they also demonstrate good performance under belief propagation decoding, in addition to low decoding complexity.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/332972

Decentralized Biometric Authentication based on Fuzzy Commitments and Blockchain
Proceedings of the the Sixth International Conference on Blockchain Computing and Applications (BCCA 2024)
Autore/i: Abo Alzahab, Nibras; Rafaiani, Giulia; Battaglioni, Massimo; Chiaraluce, Franco; Baldi, Marco
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Blockchain technology, which was introduced for supporting cryptocurrencies, today provides a decentralized in- frastructure for general information storage and execution of algorithms, thus enabling the conversion of many applications and services from a centralized and intermediated model to a decentralized and disintermediated one. In this paper we focus on biometric authentication, which is classically performed using centralized systems, and could hence benefit from decentraliza- tion. For such a purpose, however, an inherent contradiction between biometric applications and blockchain technology must be overcome, as the former require keeping biometric features private, while blockchain is a public infrastructure. We propose a blockchain-based biometric authentication protocol that enables decentralization and resilience while protecting the privacy, personal data, and, in particular, biometric features of users. The protocol we propose leverages fuzzy commitment schemes to allow biometric authentication to be performed without disclosing biometric data. We also analyze the security of the protocol we propose by considering some relevant attacks.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/337792

Understanding the Impact of EEG Segment Length on Biometric Authentication
2024 10th International Conference on Computing, Engineering and Design, ICCED 2024
Autore/i: Abo Alzahab, Nibras; Scalise, Lorenzo; Baldi, Marco
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Biometric authentication becomes more essential as technology evolves. The ease with which a biometric can be used affects its impact and industrial implementation. One promising biometric is electroencephalography (EEG). This paper investigates how to optimize identification accuracy in EEG-based biometric authentication without overly complicating or slowing down the system. To determine the point at which the EEG data is most useful for authentication, we examine various segment lengths of the data and apply machine learning models. Our research will contribute to the advancement of EEG biometric technologies by offering a safe and convenient identity verification solution. The research shows that accuracy increases by increasing the EEG segment length until reaching a turning point and then continuing with a plateau. The turning point was statistically determined to be 2 seconds. This finding contributes to the possibility of applying EEG-based biometric authentication in uncontrolled real-world settings.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/345074

AoA-Based Physical Layer Authentication in Analog Arrays under Impersonation Attacks
2024 IEEE 25th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)
Autore/i: Srinivasan, Muralikrishnan; Senigagliesi, Linda; Chen, Hui; Chorti, Arsenia; Baldi, Marco; Wymeersch, Henk
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: We discuss the use of angle of arrival (AoA) as an authentication measure in analog array multiple-input multiple-output (MIMO) systems. A base station equipped with an analog array authenticates users based on the AoA estimated from certified pilot transmissions, while active attackers manipulate their transmitted signals to mount impersonation attacks. We study several attacks of increasing intensity (captured through the availability of side information at the attackers) and assess the performance of AoA-based authentication using one-class classifiers. Our results show that some attack techniques with knowledge of the combiners at the verifier are effective in falsifying the AoA and compromising the security of the considered type of physical layer authentication.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/336476

Using Graph Theory for Improving Machine Learning-based Detection of Cyber Attacks
25th IEEE International Conference on High Performance Switching and Routing (HPSR 2024): Proceedings
Autore/i: Zonneveld, Giacomo; Principi, Lorenzo; Baldi, Marco
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Early detection of network intrusion attempts is one of the main pillars of cybersecurity. An effective approach in this regard consists in analyzing network traffic with the help of artificial intelligence algorithms, with the aim of detecting the possible presence of an attacker by distinguishing it from a legitimate user. This is commonly done by collecting the traffic exchanged between terminals in a network and analyzing it on a per-packet or per-connection basis. In this paper, we propose instead to perform pre-processing of network traffic under analysis with the aim of extracting some new metrics, on which we can perform detection more efficiently and overcome some limitations of classical approaches. These new metrics are based on graph theory, and consider the network as a whole, rather than focusing on individual packets or connections. Our approach is validated through experiments performed on publicly available data sets, from which it turns out not only to overcome some of the limitations of classical approaches, but also achieve an improved detection capability of intrusion attempts.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/334395

Applying Intrusion Detection Based on Algorithmically Generated Domain Classification to Real Network Traffic
1st International Conference on Cyber Security and Computing 2024, CyberComp 2024
Autore/i: Principi, Lorenzo; Baldi, Marco
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Domain Generation Algorithms (DGAs) are used by malware in establishing a connection with the Command and Control (C&C) server, to reduce the risk of the connection being identified by changing the C&C domain name dynamically but predictably. Since malicious Algorithmically-Generated Domains (mAGDs) have identifiable patterns, suitably trained Machine Learning (ML) models, here called mAGD classifiers, are often able to identify such domains. However, these results are typically obtained in a non-temporal context, raising uncertainty about their applicability in real-world scenarios. In reality, network traffic is time-dependent and extremely variable, and false positives have a significant impact. One way to mitigate these problems is to analyze connections not one at a time, but by grouping those occurring in a predetermined time interval. In this paper we address such a challenge, showing that, even when the mAGD classifier has very good performance in classifying individual domain names, its output needs to be carefully post-processed in order to achieve good overall intrusion detection performance on real network traffic.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/342712

Bounds on the Free Distance of Periodically Time-Varying SC-LDPC Codes
IEEE TRANSACTIONS ON INFORMATION THEORY
Autore/i: Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco
Classificazione: 1 Contributo su Rivista
Abstract: Time-invariant spatially coupled low-density parity-check (TI-SC-LDPC) codes can be obtained by unwrapping quasi-cyclic (QC) LDPC codes. This results in a free distance that is lower bounded by the minimum distance of the underlying QC-LDPC codes. By introducing some variability in the syndrome former matrix, time-varying (TV) SC-LDPC codes are obtained, which trade an improved error correction performance for an increased decoding memory requirement and decoding complexity. A family of codes able to combine the advantages of TI-SC-LDPC codes with those of TV-SC-LDPC codes is that of periodically time-varying (PTV) SC-LDPC codes, based on a finite and periodic variation of the syndrome former matrix. In this paper we focus on such codes, and derive new upper bounds on the free distance of PTV-SC-LDPC code ensembles as well as on specific codes. By using these bounds, we show that PTV-SC-LDPC codes can achieve important improvements in the free distance over TI-SC-LDPC codes even using a very small period of variability, which corresponds to a minimal increase in memory and complexity. We also validate the new upper bounds through numerical experiments and assess the error correction performance of the corresponding codes through Monte Carlo simulations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/326655

Auditory evoked potential electroencephalography-biometric dataset
DATA IN BRIEF
Autore/i: Alzahab, Nibras Abo; Iorio, Angelo Di; Apollonio, Luca; Alshalak, Muaaz; Gravina, Alessandro; Antognoli, Luca; Baldi, Marco; Scalise, Lorenzo; Alchalabi, Bilal
Classificazione: 1 Contributo su Rivista
Abstract: This work aims to assess the use of electroencephalographic (EEG) signals as a means of biometric authentication. More than 240 recordings, each lasting 2 min, were gathered from 20 subjects involved in the data collection. Data include the results of experiments performed both in a resting state and in the presence of auditory stimuli. The resting-state EEG sig- nals were acquired with both open and closed eyes. The au- ditory stimuli EEG signals consist of six experiments divided into two scenarios. The first scenario considers in-ear stimuli, while the second scenario considers bone-conducting stimuli. For each of the two scenarios, experiments include a native language song, a non-native language song and some neutral music. This data could be used to develop biometric systems for authentication or identification. Additionally, they could be used to study the effect of auditory stimuli such as music on EEG activity and to compare it with the resting state con- dition.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/337032

Rate-compatible LDPC Codes based on Primitive Polynomials and Golomb Rulers
IEEE TRANSACTIONS ON COMMUNICATIONS
Autore/i: Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco; Cancellieri, Giovanni
Classificazione: 1 Contributo su Rivista
Abstract: We introduce and study a family of rate-compatible Low-Density Parity-Check (LDPC) codes. The design of these codes starts from simplex codes, defined by parity-check matrices having a simple form stemming from the coefficients of a primitive polynomial. For this reason, we call the new codes Primitive Rate-Compatible LDPC (PRC-LDPC) codes. By applying puncturing to these codes, we obtain a bit-level granularity of the code rate. We show that, in order to achieve good LDPC codes, the underlying polynomials, besides being primitive, must meet some more stringent conditions with respect to those of classical punctured simplex codes. We leverage non-modular Golomb rulers to take these new requirements into account. We characterize the minimum distance properties of PRC-LDPC codes, and study and discuss their encoding and decoding complexity. Finally, we assess the error rate performance of high rate PRC-LDPC codes under iterative decoding.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/332273

BiometricIdentity dApp: Decentralized biometric authentication based on fuzzy commitment and blockchain
SOFTWAREX
Autore/i: ABO ALZAHAB, Nibras; Rafaiani, Giulia; Battaglioni, Massimo; Cavalli, Ana; Chiaraluce, Franco; Baldi, Marco
Classificazione: 1 Contributo su Rivista
Abstract: As biometric authentication has been increasingly integrated into cutting-edge technology, it is interesting to study how its level of trust and interoperability across multiple devices can be increased. They can actually be enhanced through decentralization, particularly by using blockchain technology. Since transaction data on the blockchain are open and readable by all parties, a high level of user trust is achieved, enhancing transparency and interoperability across the network. The software we propose bridges the gap between the security of biometric information and the transparency of blockchain and decentralized technologies. Specifically, the software is a decentralized application (dApp), based on the Ethereum blockchain, which relies on a smart contract to manage its logic. The logic of the smart contract employs the fuzzy commitment scheme (FCS) to securely hash biometric templates, while always maintaining fault tolerance thanks to error correction codes (ECC). This mechanism ensures data integrity within a transparent, decentralized framework. The proposed dApp enhances biometric authentication by supporting both the enrollment and authentication processes. Its smart contract enables managing access control within this decentralized infrastructure. In practical applications, the proposed system can demonstrate its potential as a secure and decentralized alternative to traditional centralized systems.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/336502

Royal Rumbles in Cryptography: the NIST PQC Competition
CIFRIS23 ACTA
Autore/i: Baldi, Marco
Editore: De Cifris Press
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/332552

SPANSE: Combining sparsity with density for efficient one-time code-based digital signatures
JOURNAL OF ALGEBRA AND ITS APPLICATIONS
Autore/i: Baldi, Marco; Chiaraluce, Franco; Santini, Paolo
Classificazione: 1 Contributo su Rivista
Abstract: The use of codes defined by sparse characteristic matrices, like QC-LDPC and QCMDPC codes, has become an established solution to design secure and efficient code-based public-key encryption schemes, as also witnessed by the ongoing NIST postquantum cryptography standardization process. However, similar approaches have been less fortunate in the context of code-based digital signatures, since no secure and efficient signature scheme based on these codes is available to date. The main limitation of previous attempts in this line of research has been the use of sparse signatures, which produces some leakage of information about the private key. In this paper, we propose a new code-based digital signature scheme that overcomes such a problem by publishing signatures that are abnormally dense, rather than sparse. This eliminates the possibility of deducing information from the sparsity of signatures, and follows a recent trend in code-based cryptography exploiting the hardness of the decoding problem for largeweight vectors, instead of its classical version based on small-weight vectors. We focus on one-Time use and provide a first parameterization of the new scheme, the main advantages of which are very fast signature generation and verification, and public keys that are not too large for a code-based signature scheme.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325291

Group Codes with Low-Density Orthogonal Idempotent
2024 IEEE International Symposium on Information Theory: Proceedings
Autore/i: Molina, Fabian; Santini, Paolo; Baldi, Marco
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: We introduce the family of Low-Density Orthogonal Idempotent (LDOI) codes, which are group codes characterized by two-sided ideals of a semisimple group algebra that have an orthogonal idempotent with low Hamming weight. These codes can be thought of as the analog, over a group algebra, of Low-Density Parity-Check (LDPC) codes over finite fields. We initiate the study of LDOI codes and characterize some of their properties in terms of weight of the orthogonal idempotent and the so-called adjacency matrix. We then show how the iterative Bit Flipping (BF) algorithm-the simplest form of decoder used for LDPC codes-can be adapted to decode LDOI codes. We show that, for certain families of LDOI codes (namely, those having a binary adjacency matrix), the BF decoder is optimal (i.e., achieves maximum error correction capability) even when just one iteration is performed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/334397

Zero Knowledge Protocols and Signatures from the Restricted Syndrome Decoding Problem
Public-Key Cryptography - PKC 2024
Autore/i: Baldi, Marco; Bitzer, Sebastian; Pavoni, Alessio; Santini, Paolo; Wachter-Zeh, Antonia; Weger, Violetta
Editore: SPRINGER INTERNATIONAL PUBLISHING AG
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The Restricted Syndrome Decoding Problem (R-SDP) corresponds to the Syndrome Decoding Problem (SDP) with the additional constraint that all entries of the solution error vector must live in a fixed subset of the finite field. In this paper, we study how this problem can be applied to the construction of signatures derived from Zero-Knowledge (ZK) protocols. First, we show that R-SDP appears to be well-suited for this type of application: ZK protocols relying on SDP can easily be modified to use R-SDP, resulting in significant reductions in the communication cost. We then introduce and analyze a variant of R-SDP, which we call R-SDP(G), with the property that solution vectors can be represented with a number of bits that is slightly larger than the security parameter (which clearly provides an ultimate lower bound). This enables the design of competitive ZK protocols. We show that existing ZK protocols can greatly benefit from the use of R-SDP, achieving signature sizes in the order of 7 kB, which are smaller than those of several other schemes submitted to NIST's additional call for post-quantum digital signatures.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/334572

Computational Hardness of the Permuted Kernel and Subcode Equivalence Problems
IEEE TRANSACTIONS ON INFORMATION THEORY
Autore/i: Santini, Paolo; Baldi, Marco; Chiaraluce, Franco
Classificazione: 1 Contributo su Rivista
Abstract: The Permuted Kernel Problem (PKP) asks to find a permutation which maps an input matrix into the kernel of some given vector space. The literature exhibits several works studying its hardness in the case of the input matrix being mono-dimensional (i.e., a vector), while the multi-dimensional case has received much less attention and, de facto, only the case of a binary ambient finite field has been studied. The Subcode Equivalence Problem (SEP), instead, asks to find a permutation so that a given linear code becomes a subcode of another given code. At the best of our knowledge, no algorithm to solve the SEP has ever been proposed. In this paper we study the computational hardness of solving these problems. We first show that, despite going by different names, PKP and SEP are exactly the same problem. Then we consider the state-of-the-art solver for the mono-dimensional PKP (namely, the KMP algorithm, proposed by Koussa, Macario-Rat and Patarin), generalize it to the multi-dimensional case and analyze both the finite and the asymptotic regimes. We further propose a new algorithm, which can be thought of as a refinement of KMP. In the asymptotic regime our algorithm does not improve on KMP but, in the finite regime (and for parameters of practical interest), we achieve significant improvements, especially for the multi-dimensional version of PKP. As an evidence, we show that it is the fastest algorithm to attack several recommended instances of cryptosystems based on PKP. As a side-effect, given the mentioned equivalence between PKP and SEP, all the algorithms we analyze in this paper can be used to solve instances of the latter problem.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325875

Physical Layer Security and Authentication with Practical Transmissions
Towards a Trustworthy Information Exchange in the Digital Era
Autore/i: Senigagliesi, L.; Baldi, M.; Gambi, E.; Chiaraluce, F.
Editore: Texmat
Luogo di pubblicazione: Roma
Classificazione: 2 Contributo in Volume
Abstract: Classic approaches to communications security neglect the physical layer and rely on computational security solutions working at higher layers, like cryptography. However, the physical layer of communications provides for some interesting properties that may be significant for security, like uniqueness, randomness and reciprocity. In this chapter we give an overview of techniques that allow achieving confidentiality and authentication at the physical layer taking into account the typical constraints of practical transmissions, like finite-length coding and discrete modulation formats. We show that, even with these constraints in mind, the physical layer can be a source of security for communications, both in terms of confidentiality and authentication, and provides a basis for hardening security at higher layers.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/320051

Efficiency of Malware Detection Based on DNS Packet Analysis Over Real Network Traffic
Proceedings 2023 IEEE International Conference on Cyber Security and Resilience (CSR 2023)
Autore/i: Principi, Lorenzo; Baldi, Marco; Cucchiarelli, Alessandro; Spalazzi, Luca
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/320971

Generic Decoding of Restricted Errors
Proceedings 2023 IEEE International Symposium on Information Theory (ISIT 2023)
Autore/i: Bitzer, Sebastian; Pavoni, Alessio; Weger, Violetta; Santini, Paolo; Baldi, Marco; Wachter-Zeh, Antonia
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Several recently proposed code-based cryptosystems base their security on a slightly generalized version of the classical (syndrome) decoding problem. Namely, in the so-called restricted (syndrome) decoding problem, the error values stem from a restricted set. In this paper, we propose new generic decoders, that are inspired by subset sum solvers and tailored to the new setting. The introduced algorithms take the restricted structure of the error set into account in order to utilize the representation technique efficiently. This leads to a considerable decrease in the security levels of recently published code-based cryptosystems.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/322711

Rate-Adaptive LDPC Codes Obtained from Simplex Codes
Proceedings of the IEEE International Conference on Communications (ICC) 2023
Autore/i: Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco; Cancellieri, Giovanni
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper we show that, when a binary primitive polynomial can be associated to a sparse Golomb ruler, the simplex code obtained by taking it as the code parity-check polynomial exhibits good distance properties and performance. We define some conditions under which the obtained codes are also Low-Density Parity-Check (LDPC) codes, and can hence be decoded through efficient iterative algorithms. We perform code puncturing, leading to a family of rate-adaptive codes, and we predict some of their structural properties in terms of minimum distance and weight distribution. We show that, in addition to having some useful properties, these codes achieve good performance in terms of error rate under LDPC decoding.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/319091

Machine Learning-based Robust Physical Layer Authentication Using Angle of Arrival Estimation
Proceedings of the IEEE Global Communications Conference (GLOBECOM) 2023
Autore/i: Pham, Thuy M.; Senigagliesi, Linda; Baldi, Marco; P., Fettweis Gerhard; Chorti, Arsenia
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper, we study the potential use of the angle of arrival (AoA) as a feature for performing robust, machine learning (ML) based physical layer authentication (PLA). In fact, whereas most previous research on PLA relies on physical properties such as channel state information or received signal strength, the use of the AoA in this context is not yet extensively researched from a robustness point of view, i.e., as the means to provide resistance to impersonation (location spoofing) attacks. In this study, we first prove that an effective impersonation attack on AoA estimation can only be done under very stringent conditions on the attacker in terms of location and hardware capabilities, and thus, the AoA can in many scenarios be used as a robust feature for authentication. In addition, we utilize machine learning in our study to provide lightweight, model-free, intelligent authentication. We demonstrate the effectiveness of the proposed PLA solutions by running the algorithms on experimental outdoor massive multiple input multiple output data.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325840

A Machine Learning-based Method for Cyber Risk Assessment
Proceedings of the IEEE 36th International Symposium on Computer Based Medical Systems (CBMS) 2023
Autore/i: Rafaiani, Giulia; Battaglioni, Massimo; Compagnoni, Simone; Senigagliesi, Linda; Chiaraluce, Franco; Baldi, Marco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Cyber risk assessment is one of the top priorities of modern organizations and companies, owing to the massive amount of data they process on a daily basis and to the increasing number of successful cyber attacks. The probability of occurrence of these cyber incidents can be estimated by means of statistical tools, which exploit numerical categories to compute the probability that the organization will be breached by one or more cyber attacks. However, these approaches heavily rely on experts' estimates and/or on past data, which are not always available. In this paper we show that, by exploiting machine learning tools, cyber risk can be assessed by using some easily obtainable parameters (called maturity, complexity, attractiveness) representing the cyber posture of the organization under exam. To validate the method we propose, we apply it to three organizations in the healthcare sector having different values of maturity and complexity. The results highlight how the model can be successfully used to assign each organization a class of cyber risk, even in a crucial sector such as healthcare.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/319354

A Quantitative Model for the Assessment of Ethics Risks in Information Technology
Proceedings of the IEEE International Symposium on Ethics in Engineering, Science, and Technology (ETHICS) 2023
Autore/i: Rafaiani, Giulia; Barchiesi, Giorgia; Ilari, Ludovica; Baldi, Marco; Giovanola, Benedetta
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The management of sensitive and personal data in the healthcare sector must guarantee the widest respect of patients' fundamental rights. However, some quantitative evaluation framework for assessing the level of ethical compliance of a technology to the most important ethical principles is still missing. In this work, we first provide a model to quantitatively assess constitutive ethics, i.e., the intrinsic ethical compliance of a technology. Secondly, we propose a method for quantitatively assessing circumstantial ethics risks of a technology, when used in some specific context. Our ethics risk assessment model is based on the evaluation of the compliance of the technology to a defined set of controls about some ethical principles and about the robustness of the technological infrastructure underneath. Then, we validate our model by applying it to some recent healthrelated blockchain frameworks, and we compare a qualitative ethical assessment with the quantitative assessment made with the proposed model for constitutive ethics compliance. Through our assessment, we identify some technical choices that achieve the highest ethical scores, such as using a permissioned blockchain, off-chain storage, and encryption of data. Finally, we observe that the principles of privacy and data governance turn out to be the most satisfied ethical principles, contrary to fairness.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/318812

A blockchain consensus protocol based on fuzzy signatures
Proceedings of the IEEE Global Communications Conference (GLOBECOM) 2023
Autore/i: Santini, Paolo; Rafaiani, Giulia; Battaglioni, Massimo; Chiaraluce, Franco; Baldi, Marco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: We propose a protocol to jointly achieve authentication and consensus on a blockchain network, in which endpoints are required to digitally sign some random message using fuzzy keys according to a classic fuzzy signature paradigm typical, for example, of biometric authentication. We consider classic RSA digital signatures, showing that fuzziness in the secret key translates into some noise affecting the derived signatures. The removal of such a noise provides the basis for building a blockchain consensus mechanism, which we name Proof of Fuzzy Signature (PoFS). It basically provides a special instance of Proof of Work in which the mining process corresponds to the de-noising process of RSA digital signatures derived from fuzzy keys. This way, the authentication process is delegated to a distributed network and, at the same time, requires executing the useful task of removing noise from fuzzy signatures.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/325416

Optimizing quasi-cyclic spatially coupled LDPC codes by eliminating harmful objects
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING
Autore/i: Battaglioni, Massimo; Chiaraluce, Franco; Baldi, Marco; Pacenti, Michele; Mitchell, David G. M.
Classificazione: 1 Contributo su Rivista
Abstract: It is well known that some harmful objects in the Tanner graph of low-density parity-check (LDPC) codes have a negative impact on their error correction performance under iterative message-passing decoding. Depending on the channel and the decoding algorithm, these harmful objects are different in nature and can be stopping sets, trapping sets, absorbing sets, or pseudocodewords. Differently from LDPC block codes, the design of spatially coupled LDPC codes must take into account the semi-infinite nature of the code, while still reducing the number of harmful objects as much as possible. We propose a general procedure, based on edge spreading, enabling the design of good quasi-cyclic spatially coupled LDPC (QC-SC-LDPC) codes. These codes are derived from quasi-cyclic LDPC (QC-LDPC) block codes and contain a considerably reduced number of harmful objects with respect to the original QC-LDPC block codes. We use an efficient way of enumerating harmful objects in QC-SC-LDPCCs to obtain a fast algorithm that spans the search space of potential candidates to select those minimizing the multiplicity of the target harmful objects. We validate the effectiveness of our method via numerical simulations, showing that the newly designed codes achieve better error rate performance than codes presented in previous literature.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/319711

Ethical Biases in Machine Learning-based Filtering of Internet Communications
Proceedings of the IEEE International Symposium on Ethics in Engineering, Science, and Technology (ETHICS) 2023
Autore/i: Ilari, Ludovica; Rafaiani, Giulia; Baldi, Marco; Giovanola, Benedetta
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The use of automated systems based on artificial intelligence and machine learning for filtering and moderating online communications has become commonplace. While this allows for high levels of efficiency and fine-grained control of malicious behaviors, it could also produce unintended disparities in treatment of legitimate users. In this paper, we aim at identifying some possible field-related biases in the well-known Google Perspective API machine learning-based engine for controlling Internet communications. For this purpose, we consider communications in the fields of health, trade, finance, and defense and build a data set collecting Twitter-based online communications of the World Health Organization (WHO), World Trade Organization (WTO), International Monetary Fund (IMF) and North Atlantic Treaty Organization (NATO). Collected data are then analyzed through Perspective API to assign them an alleged likelihood of being abusive for specific emotional concepts, referred to as attributes. Upon analysis, discrimination between the considered users is identified for all attributes. This result, although preliminary, apparently indicates that Perspective API creates discrimination for field-related content as a result of semantic biases in the data, thus highlighting the need for an ethically sound design of these systems, following an ethics by design approach.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/318811

Analysis of a Blockchain Protocol Based on LDPC Codes
Proceedings of the 4th Workshop on Distributed Ledger Technology co-located with the Italian Conference on Cybersecurity 2022 (ITASEC 2022)
Autore/i: Battaglioni, Massimo; Santini, Paolo; Rafaiani, Giulia; Chiaraluce, Franco; Baldi, Marco
Editore: Maurizio Pizzonia, Andrea Vitaletti
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In a blockchain Data Availability Attack (DAA), a malicious node publishes a block header but withholds part of the block, which contains invalid transactions. Honest full nodes, which can download and store the full ledger, are aware that some data are not available but they have no formal way to prove it to light nodes, i.e., nodes that have limited resources and are not able to access the whole blockchain data. A common solution to counter these attacks exploits linear error correcting codes to encode the block content. A recent protocol, called SPAR, employs coded Merkle trees and low-density parity-check codes to counter DAAs. In this paper, we show that the protocol is less secure than claimed, owing to a redefinition of the adversarial success probability. As a consequence we show that, for some realistic choices of the parameters, the total amount of data downloaded by light nodes is larger than that obtainable with competing solutions.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/304486

MAGIC: A Method for Assessing Cyber Incidents Occurrence
IEEE ACCESS
Autore/i: Battaglioni, Massimo; Rafaiani, Giulia; Chiaraluce, Franco; Baldi, Marco
Classificazione: 1 Contributo su Rivista
Abstract: The assessment of cyber risk plays a crucial role for cybersecurity management, and has become a compulsory task for certain types of companies and organizations. This makes the demand for reliable cyber risk assessment tools continuously increasing, especially concerning quantitative tools based on statistical approaches. Probabilistic cyber risk assessment methods, however, follow the general paradigm of probabilistic risk assessment, which requires the magnitude and the likelihood of incidents as inputs. Unfortunately, for cyber incidents, the likelihood of occurrence is hard to estimate based on historical and publicly available data; so, expert evaluations are commonly used, which however leave space to subjectivity. In this paper, we propose a novel probabilistic model, called MAGIC (Method for AssessinG cyber Incidents oCcurrence), to compute the likelihood of occurrence of a cyber incident, based on the evaluation of the cyber posture of the target organization. This allows deriving tailor-made inputs for probabilistic risk assessment methods, like HTMA (How To Measure Anything in cybersecurity risk), FAIR (Factor Analysis of Information Risk) and others, thus considerably reducing the margin of subjectivity in the assessment of cyber risk. We corroborate our approach through a qualitative and a quantitative comparison with several existing methods
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/304519

Implementation of Ethereum accounts and transactions on embedded IoT devices
2022 IEEE International Conference on Omni-layer Intelligent Systems (COINS) - Proceedings
Autore/i: Rafaiani, G.; Santini, P.; Baldi, M.; Chiaraluce, F.
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The growing interest in Internet of Things (IoT) and Industrial IoT (IIoT) poses the challenge of finding robust solutions for the certification and notarization of data produced and collected by embedded devices. The blockchain and distributed ledger technologies represent a promising solution to address these issues, but rise other questions, for example regarding their practical feasibility. In fact, IoT devices have limited resources and, consequently, may not be able to easily perform all the operations required to participate in a blockchain. In this paper we propose a minimal architecture to allow IoT devices performing data certification and notarization on the Ethereum blockchain. We develop a hardware-software platform through which a lightweight device (e.g., an IoT sensor), holding a secret key and the associated public address, produces signed transactions, which are then submitted to the blockchain network. This guarantees data integrity and authenticity and, on the other hand, minimizes the computational burden on the lightweight device. To show the practicality of the proposed approach, we report and discuss the results of benchmarks performed on ARM Cortex-M4 hardware architectures, sending transactions over the Ropsten testnet. Our results show that all the necessary operations can be performed with small latency, thus proving that an IoT device can directly interact with the blockchain, without apparent bottlenecks.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/305599

A novel attack to the permuted kernel problem
2022 IEEE International Symposium on Information Theory (ISIT)
Autore/i: Santini, P.; Baldi, M.; Chiaraluce, F.
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The Permuted Kernel Problem (PKP) asks to find a permutation of a given vector belonging to the kernel of a given matrix. The PKP is at the basis of PKP-DSS, a post-quantum signature scheme deriving from the identification scheme proposed by Shamir in 1989. The most efficient solver for PKP is due to a recent paper by Koussa et al. In this paper we propose an improvement of such an algorithm, which we achieve by considering an additional collision search step applied on kernel equations involving a small number of coordinates. We study the conditions for such equations to exist from a coding theory perspective, and we describe how to efficiently find them with methods borrowed from coding theory, such as information set decoding. We assess the complexity of the resulting algorithm and show that it outperforms previous approaches in several cases. We also show that, taking the new solver into account, the security level of some instances of PKP-DSS turns out to be slightly overestimated.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/304261

Performance Bounds for QC-MDPC Codes Decoders
Code-Based Cryptography
Autore/i: Baldi, Marco; Barenghi, Alessandro; Chiaraluce, Franco; Pelosi, Gerardo; Santini, Paolo
Editore: Springer
Classificazione: 2 Contributo in Volume
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/297125

Effect of Auditory Stimuli on Electroencephalography-based Authentication
2022 IEEE International Workshop on Metrology for Extended Reality, Artificial Intelligence and Neural Engineering (MetroXRAINE 2022) - Proceedings
Autore/i: Alzahab, Nibras Abo; Iorio, Angelo Di; Baldi, Marco; Scalise, Lorenzo
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In contrast with standard authentication methods based on credentials, biometric-based authentication has lately emerged as a viable paradigm for attaining rapid and secure authentication of users. Among the numerous categories of biometric traits, electroencephalogram (EEG)-based biometrics is recognized as a promising method owing to its unique characteristics. This paper provides an experimental evaluation of the effect of auditory stimuli (AS) on EEG-based biometrics by studying the following features: i) general change in AS-aided EEG-based biometric authentication in comparison with nonAS-aided EEG-based biometric authentication, ii) role of the language of the AS and ii) influence of the conduction method of the AS. Our results show that the presence of an AS can improve authentication performance by 9.27 %. Additionally, the performance achieved with an in-ear AS is better than that obtained using a bone-conducting AS. Finally, we verify that performance is independent of the language of the AS. The results of this work provide a step forward towards designing a robust EEG-based authentication system.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/309752

Reproducible families of codes and cryptographic applications
JOURNAL OF MATHEMATICAL CRYPTOLOGY
Autore/i: Santini, Paolo; Persichetti, Edoardo; Baldi, Marco
Classificazione: 1 Contributo su Rivista
Abstract: Structured linear block codes such as cyclic, quasi-cyclic and quasi-dyadic codes have gained an increasing role in recent years both in the context of error control and in that of code-based cryptography. Some well known families of structured linear block codes have been separately and intensively studied, without searching for possible bridges between them. In this article, we start from well known examples of this type and generalize them into a wider class of codes that we call â.,±-reproducible codes. Some families of â.,±-reproducible codes have the property that they can be entirely generated from a small number of signature vectors, and consequently admit matrices that can be described in a very compact way. We denote these codes as compactly reproducible codes and show that they encompass known families of compactly describable codes such as quasi-cyclic and quasi-dyadic codes. We then consider some cryptographic applications of codes of this type and show that their use can be advantageous for hindering some current attacks against cryptosystems relying on structured codes. This suggests that the general framework we introduce may enable future developments of code-based cryptography.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/292101

Uncovering the potential of blockchain in the agri-food supply chain: An interdisciplinary case study
JOURNAL OF ENGINEERING AND TECHNOLOGY MANAGEMENT
Autore/i: Compagnucci, L.; Lepore, D.; Spigarelli, F.; Frontoni, E.; Baldi, M.; Di Berardino, L.
Classificazione: 1 Contributo su Rivista
Abstract: This paper explores how Blockchain technology (BCT) can be integrated in the agri-food supply chain (ASC) and how BCT-based networks are formed. To do this, the paper describes a BCT solution, designed to enhance traceability, and analyses its adoption in two small firms. Adopting an interdisciplinary approach and the Actor-Network Theory (ANT), the findings have revealed that BCT improves how data is collected and has changed how firms interact with stakeholders and customers. Firms have enhanced their reputations and started targeting new domestic and international markets. Technical and economic challenges were found when persuading actors to participate in the BCT-based network.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/305239

Optimization of a Reed-Solomon code-based protocol against blockchain data availability attacks
Proceedings of the IEEE International Conference on Communications (ICC) 2022
Autore/i: Santini, Paolo; Rafaiani, Giulia; Battaglioni, Massimo; Chiaraluce, Franco; Baldi, Marco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: ASBK is a recent blockchain protocol tackling data availability attacks against light nodes; it employs twodimensional Reed-Solomon codes to encode the list of transactions and a random sampling phase where adversaries are forced to reveal information. In its original formulation, only codes with rate 1/4 are considered, and a theoretical analysis requiring computationally demanding formulas is provided. This makes ASBK difficult to optimize in situations of practical interest. In this paper, we introduce a much simpler model for such a protocol, which additionally supports the use of codes with arbitrary rate. This makes blockchains implementing ASBK much easier to design and optimize. Furthermore, disposing of a clearer view of the protocol, some general features and considerations can be derived. As a concrete application, we consider relevant blockchain parameters and find network settings that minimize the amount of data downloaded by light nodes. Our results show that the protocol benefits from the use of codes defined over large finite fields, with code rates that may be even significantly different from the originally proposed one.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/300584

Authentication at the Physical Layer with Cooperative Communications and Machine Learning
2022 Joint European Conference on Networks and Communications & 6G Summit (EuCNC/6G Summit)
Autore/i: Senigagliesi, Linda; Baldi, Marco; Gambi, Ennio
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/304485

Cyber risk assessment: a pragmatic approach
Proceedings of the 1st International Conference on Information Technologies and Educational Engineering (ICITEE21)
Autore/i: Rafaiani, Giulia; Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Nowadays, cyber security plays a crucial role for any organization. Na-tional and international data protection regulations require particular attention tocyber risk assessment and cyber risk management. Many efforts have been devotedto the development of efficient tools and methods for cyber risk assessment. How-ever, existing methodologies often lack straightforwardness, and their implementa-tion is difficult in real case scenarios. The aim of this paper is to provide an intuitivebut quantitative model to estimate the likelihood of occurrence of a cyber threat in acertain period of time. Then, a cyber risk index can be obtained by multiplying sucha quantity by the impact of the corresponding threat. Our model combines maturityand complexity indexes with the attractiveness of the considered organization byexploiting a generalized logistic function and the properties of conditional probabil-ities. Numerical examples are provided to confirm practicality of the method.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/293324

Analysis of In-Place Randomized Bit-Flipping Decoders for the Design of LDPC and MDPC Code-Based Cryptosystems
E-Business and Telecommunications
Autore/i: Baldi, Marco; Barenghi, Alessandro; Chiaraluce, Franco; Pelosi, Gerardo; Santini, Paolo
Editore: Springer
Classificazione: 2 Contributo in Volume
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/292988

Efficient hardware implementation of the LEDAcrypt decoder
IEEE ACCESS
Autore/i: Koleci, K.; Santini, P.; Baldi, M.; Chiaraluce, F.; Martina, M.; Masera, G.
Classificazione: 1 Contributo su Rivista
Abstract: This work describes an efficient implementation of the iterative decoder that is the main part of the decryption stage in the LEDAcrypt cryptosystem, recently proposed for post-quantum cryptography based on low-density parity-check (LDPC) codes. The implementation we present exploits the structure of the variables in order to accelerate the decoding process while keeping the area bounded. In particular, our focus is on the design of an efficient multiplier, the latter being a fundamental component also in view of considering different values of the cryptosystem's parameters, as it might be required in future applications. We aim to provide an architecture suitable for low cost implementation on both Field Programmable Gate Array (FPGA) and Application Specific Integrated Circuit (ASIC) implementations. As for the FPGA, the total execution time is 0.6 ms on the Artix-7 200 platform, employing at most 30% of the total available memory, 15% of the total available Look-up Tables and 3% of the Flip-Flops. The ASIC synthesis has been performed for both STM FDSOI 28 nm and UMC CMOS 65 nm technologies. After logic synthesis with the STM FDSOI 28 nm, the proposed decoder achieves a total latency of 0.15 ms and an area occupation of 0.09 mm2. The post-Place&Route implementation results for the UMC 65 nm show a total execution time of 0.3 ms, with an area occupation of 0.42 mm2 and a power consumption of at most 10.5 mW.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/290077

Next generation earth‑to‑space telecommand coding and synchronization: ground system design, optimization and software implementation
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING
Autore/i: Abelló, Ricard; Baldi, Marco; Carvalho, Filipe; Chiaraluce, Franco; Fernandes, Ricardo; Garello, Roberto; Paolini, Enrico; Prata, Ricardo
Classificazione: 1 Contributo su Rivista
Abstract: The Consultative Committee for Space Data Systems, followed by all national and international space agencies, has updated the Telecommand Coding and Synchronization sublayer to introduce new powerful low-density parity-check (LDPC) codes. Their large coding gains significantly improve the system performance and allow new Telecommand services and profiles with higher bit rates and volumes. In this paper, we focus on the Telecommand transmitter implementation in the Ground Station baseband segment. First, we discuss the most important blocks and we focus on the most critical one, i.e., the LDPC encoder. We present and analyze two techniques, one based on a Shift Register Adder Accumulator and the other on Winograd convolution both exploiting the block circulant nature of the LDPC matrix. We show that these techniques provide a significant complexity reduction with respect to the usual encoder mapping, thus allowing to obtain high uplink bit rates. We then discuss the choice of a proper hardware or software platform, and we show that a Central Processing Unit-based software solution is able to achieve the high bit rates requested by the new Telecommand applications. Finally, we present the results of a set of tests on the real-time software implementation of the new system, comparing the performance achievable with the different encoding options.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/294082

A functional approach to cyber risk assessment
Proceedings AEIT 2021 International Annual Conference
Autore/i: Rafaiani, Giulia; Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco; Libertini, Giovanni; Spalazzi, Luca; Cancellieri, Giovanni
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Information security has become a crucial issue not only from the technical standpoint, but also from the managerial standpoint. The necessity for organizations to understand and manage cyber risk has led to the rise of a plethora of risk assessment methods and tools. These approaches are often difficult to interpret and complex to manage for organizations. In this paper, we propose a simple and quantitative method for the estimation of the likelihood of occurrence of a cyber incident. Our approach uses a generalized logistic function and a cumulative geometric distribution to combine the maturity and the complexity of the technical infrastructure of an organization with its attractiveness towards cyber criminals.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/292462

Efficient feature selection for electroencephalogram-based authentication
Proc. 2021 IEEE International Symposium on Medical Measurements and Applications (MeMeA)
Autore/i: ABO ALZAHAB, Nibras; Baldi, Marco; Scalise, Lorenzo
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Opposed to classic authentication protocols based on credentials, biometric-based authentication has recently emerged as a promising paradigm for achieving fast and secure authentication of users. Among the several families of biometric features, electroencephalogram (EEG)-based biometrics is considered as a promising approach due to its unique characteristics. Classification systems based on machine learning allow processing of large amounts of data and performing accurate attribution of each signal to the most relevant group, thus representing an invaluable tool for EEG-based biometrics. This paper provides an experimental evaluation of the performance achievable by EEG-based biometrics employing machine learning. We consider several groups of EEG signals and propose a suitable feature extraction criterion. Then, the extracted features are used along with neural network-based classification algorithms, K Nearest Neighbours (KNN), and eXtreme Gradient Boost (XGBoost) for attributing any EEG signal to a subject. A full feature set and a reduced feature sets are considered and tested on three public data sets. The feature selection criteria are based on a correlation map among features, ANOVA F-test, and logistic regression weights. The results show that the reduced feature sets achieves a significant reduction in computation time over the full feature set, while also providing some improvement in performance.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/314096

Cryptanalysis of a Code-Based Signature scheme based on the Schnorr-Lyubashevsky framework
IEEE COMMUNICATIONS LETTERS
Autore/i: Baldi, Marco; Deneuville, Jean-Christophe; Persichetti, Edoardo; Santini, Paolo
Classificazione: 1 Contributo su Rivista
Abstract: We propose an attack on the recent attempt by Li, Xing and Yeo to produce a code-based signature scheme using the Schnorr-Lyubashevsky approach in the Hamming metric, and verify its effectiveness through numerical simulations. Differently from other (unsuccessful) proposals, this new scheme exploits rejection sampling along with dense noise vectors to hide the secret key structure in produced signatures. We show that these measures, besides yielding very slow signing times and rather long signatures, do not succeed in protecting the secret key. We are indeed able to prove the existence of a strong correlation between produced signatures, which ultimately leaks information about the secret key. To support this claim, we use both theoretical arguments and numerical evidences. Finally, we employ such a weakness to mount a full key recovery attack, which is able to recover the secret key after the observation of a bunch of signatures. Our results show that the considered scheme may be secure only for one-time usage.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291094

Algorithmically generated malicious domain names detection based on n-grams features
EXPERT SYSTEMS WITH APPLICATIONS
Autore/i: Cucchiarelli, Alessandro; Morbidoni, Christian; Spalazzi, Luca; Baldi, Marco
Classificazione: 1 Contributo su Rivista
Abstract: Botnets are one of the major cyber infections used in several criminal activities. In most botnets, a Domain Generation Algorithm (DGA) is used by bots to make DNS queries aimed at establishing the connection with the Command and Control (C&C) server. The identification of such queries by monitoring the network DNS traffic is then crucial for bot detection. In this paper we present a methodology to detect DGA generated domain names based on a supervised machine learning process, trained with a dataset of known benign and malicious domain names. The proposed approach represents the domain names through a set of features which express the similarity between the 2-grams and 3-grams in a single unclassified domain name and those in domain names known as malicious or benign. We used the Kullback-Leibner divergence and the Jaccard Index to estimate the similarity, and we tested different machine learning algorithms to classify each domain name as benign or DGA-based (with both binary and multi-class approach). The results of our experiments demonstrate that the proposed methodology, which only exploits lexical features of domain names, attains a good level of accuracy and results in a general model able to classify previously unseen domains in an effective way. It is also able to outperform some of the state-of-the-art featureless classification methods based on deep learning.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287717

Girth analysis and design of periodically time-varying SC-LDPC codes
IEEE TRANSACTIONS ON INFORMATION THEORY
Autore/i: Battaglioni, Massimo; Chiaraluce, Franco; Baldi, Marco; Lentmaier, Michael
Classificazione: 1 Contributo su Rivista
Abstract: Time-varying spatially coupled low-density parity-check (SC-LDPC) codes with very large period are characterized by significantly better error rate performance and girth properties than their time-invariant counterparts, but the number of parameters they require to be described is usually very large and unpractical. Time-invariant SC-LDPC codes, which can be seen as periodically time-varying codes with unitary period, are represented through a small number of parameters and designed exploiting few degrees of freedom, but their error rate performance and girth properties are sub-optimal. In this paper, we show that the limits of time-invariant SC-LDPC codes can be overcome by transforming them into time-varying SC-LDPC codes with very small period. In particular, we show that periodically time-varying SC-LDPC codes with small period may exhibit significantly better girth properties than the corresponding time-invariant codes by exploiting a larger number of degrees of freedom in the code design, which however scale at most linearly with the product of the code period and the size of the considered base matrix.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287763

Effect of randomizers on the power spectrum excess of space telemetry signals
INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING
Autore/i: Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco; Garello, Roberto; Vassallo, Enrico; Paolo Calzolari, Gian
Classificazione: 1 Contributo su Rivista
Abstract: This paper presents a thorough analysis of the spectral characteristics of space telemetry signals when randomizers are used to counter the power excess, that is, the increase of the power spectrum in some measurement bandwidths with respect to the transmission of an ideal random signal. We show that a long randomizer actually improves the spectral characteristics but is not able to solve some critical problems appearing when all-zero frames or almost constant data are transmitted. Suitable solutions are proposed to face these cases, ensuring a small power excess in all possible operation conditions. The impact of high-order modulations and error correcting codes is also investigated.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291053

Comparison of Statistical and Machine Learning Techniques for Physical Layer Authentication
IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY
Autore/i: Senigagliesi, Linda; Baldi, Marco; Gambi, Ennio
Classificazione: 1 Contributo su Rivista
Abstract: In this article we consider authentication at the physical layer, in which the authenticator aims at distinguishing a legitimate supplicant from an attacker on the basis of the characteristics of a set of parallel wireless channels, which are affected by time-varying fading. Moreover, the attacker's channel has a spatial correlation with the supplicant's one. In this setting, we assess and compare the performance achieved by different approaches under different channel conditions. We first consider the use of two different statistical decision methods, and we prove that using a large number of references (in the form of channel estimates) affected by different levels of time-varying fading is not beneficial from a security point of view. We then consider classification methods based on machine learning. In order to face the worst case scenario of an authenticator provided with no forged messages during training, we consider one-class classifiers. When instead the training set includes some forged messages, we resort to more conventional binary classifiers, considering the cases in which such messages are either labelled or not. For the latter case, we exploit clustering algorithms to label the training set. The performance of both nearest neighbor (NN) and support vector machine (SVM) classification techniques is evaluated. Through numerical examples, we show that under the same probability of false alarm, one-class classification (OCC) algorithms achieve the lowest probability of missed detection when a small spatial correlation exists between the main channel and the adversary one, while statistical methods are advantageous when the spatial correlation between the two channels is large.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/284706

Cryptanalysis of a code-based full-time signature
DESIGNS, CODES AND CRYPTOGRAPHY
Autore/i: Aragon, Nicolas; Baldi, Marco; Deneuville, Jean-Christophe; Khathuria, Karan; Persichetti, Edoardo; Santini, Paolo
Classificazione: 1 Contributo su Rivista
Abstract: We present an attack against a code-based signature scheme based on the Lyubashevsky protocol that was recently proposed by Song, Huang, Mu, Wu and Wang (SHMWW). The private key in the SHMWW scheme contains columns coming in part from an identity matrix and in part from a random matrix. The existence of two types of columns leads to a strong bias in the distribution of set bits in produced signatures. Our attack exploits such a bias to recover the private key from a bunch of collected signatures. We provide a theoretical analysis of the attack along with experimental evaluations, and we show that as few as 10 signatures are enough to be collected for successfully recovering the private key. As for previous attempts of adapting Lyubashevsky’s protocol to the case of code-based cryptography, the SHMWW scheme is thus proved unable to provide acceptable security. This confirms that devising secure code-based signature schemes with efficiency comparable to that of other post-quantum solutions (e.g., based on lattices) is still a challenging task
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/291093

Physical Layer Authentication with Cooperative Wireless Communications and Machine Learning
Proceedings - 2021 IEEE Latin-American Conference on Communications, LATINCOM 2021
Autore/i: Senigagliesi, L.; Baldi, M.; Gambi, E.
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Opposed to classical authentication protocols following a computational security paradigm based on secret credentials and cryptographic primitives, physical layer authentication aims at distinguishing users without shared secrets, by leveraging the natural randomness and uniqueness of transmission channels. We consider the special setting of cooperative wireless communications, in which some relay nodes are located between a supplicant and an authenticator, and we assess the performance of physical layer authentication approaches based on both statistical and machine learning techniques. We show that the presence of relay nodes enabling cooperative communications may improve the performance of physical layer authentication.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/295561

Blockchain and Privacy: Can they coexist?
Legal Technology Transformation. A Practical Assessment
Autore/i: Baldi, Marco; Calabrese, Dalila; Rafaiani, Giulia
Editore: Editoriale scientifica
Luogo di pubblicazione: Napoli
Classificazione: 2 Contributo in Volume
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287396

Security analysis of a blockchain-based protocol for the certification of academic credentials
Proceedings of the 3rd Distributed Ledger Technology Workshop
Autore/i: Chiaraluce, F.; Baldi, M.; Kodra, M.; Spalazzi, L.
Editore: CEUR-WS.org
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/275474

A Hardware Implementation for Code-based Post-quantum Asymmetric Cryptography
ITASEC 2020 - Italian Conference on Cyber Security
Autore/i: Koleci, Kristjane; Baldi, Marco; Martina, Maurizio; Masera, Guido
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/277237

Improving the minimum distance of QC-LDPC codes by removing cycles
Proc. 2020 AEIT International Annual Conference (AEIT)
Autore/i: Battaglioni, Massimo; Baldi, Marco; Cancellieri, Giovanni
Editore: IEEE
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/285053

Physical Layer Authentication Techniques based on Machine Learning with Data Compression
2020 IEEE Conference on Communications and Network Security, CNS 2020
Autore/i: Senigagliesi, L.; Baldi, M.; Gambi, E.
Editore: Institute of Electrical and Electronics Engineers Inc.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Wireless communications employing multi-carrier transmissions, like orthogonal frequency division multiplexing (OFDM) or single-carrier frequency division multiple access (SCFDMA) may involve the use of a large number of subcarriers. In Internet of Things (IoT) contexts, however, the use of such technologies implies the fast management of large amounts of samples on devices with limited memory and computational resources. The adoption of physical layer authentication protocols in IoT may suffer from this fact, especially when they exploit machine learning algorithms yielding a significant computational burden. For instance, the complexity of Nearest Neighbor classifiers strictly depends on the training set dimension, which is directly proportional to the number of used subcarriers. In order to deal with this issue, we start from a naive approach based on random sampling of the input data to extract features, and then consider more advanced data dimension reduction algorithms, such as Principal Component Analysis (PCA) and t-distributed Stochastic Neighbor Embedding (t-SNE). We show that PCA is able to guarantee the best trade-off between authentication performance and complexity, while the application of t-SNE is effective when one wants to reduce data to a very small number of features.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/285659

A Failure Rate Model of Bit-flipping Decoders for QC-LDPC and QC-MDPC Code-based Cryptosystems
Proceedings of the 17th International Joint Conference on e-Business and Telecommunications - Volume 3: SECRYPT
Autore/i: Santini, Paolo; Pelosi, Gerardo; Chiaraluce, Franco; Barenghi, Alessandro; Baldi, Marco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/287418

Complexity of statistical attacks on QC-LDPC code-based cryptosystems
IET INFORMATION SECURITY
Autore/i: Santini, Paolo; Baldi, Marco; Chiaraluce, Franco
Classificazione: 1 Contributo su Rivista
Abstract: Public-key cryptosystems built on quasi-cyclic (QC) low-density parity-check and moderate-density parity-check codes are promising candidates for post-quantum cryptography, since they are characterised by compact keys and high algorithmic efficiency. The main issue with this kind of system is represented by the fact that, since the decoding procedure is probabilistic, it may leak information about the secret key. In this work, the authors study cryptanalysis procedures that aim at recovering the secret key by exploiting this fact. They identify the phenomenon that is at the basis of these procedures and show that the QC structure plays an important role in the success of these attacks. They use a graph analogy to study the complexity of these attacks, and show that their feasibility strongly depends on the QC structure. They also devise an approach to perform full cryptanalysis by combining an information set decoding algorithm with some partial knowledge about the structure of the secret key.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271987

Analysis of the error correction capability of LDPC and MDPC codes under parallel bit-flipping decoding and application to cryptography
IEEE TRANSACTIONS ON COMMUNICATIONS
Autore/i: Santini, P.; Battaglioni, M.; Baldi, M.; Chiaraluce, F.
Classificazione: 1 Contributo su Rivista
Abstract: Iterative decoders used for decoding low-density parity-check (LDPC) and moderate-density parity-check (MDPC) codes are not characterized by a deterministic decoding radius and their error rate performance is usually assessed through intensive Monte Carlo simulations. However, several applications, like code-based cryptography, need guaranteed low values of the error rate, which are infeasible to assess through simulations, thus requiring the development of theoretical models for the error rate of these codes. Some models of this type already exist, but become computationally intractable for parameters of practical interest. Other approaches approximate the code ensemble behaviour through assumptions, which may not hold true for a specific code. We propose a theoretical analysis of the error correction capability of LDPC and MDPC codes that allows deriving tight bounds on the error rate atthe output of parallel bit-flipping decoders. Special attention is devoted to the case of codes with small girth. Single-iteration decoding is investigated through a rigorous approach, whichdoes not require any assumption and results in a guaranteed error correction capability for any single code. We show an example of application of the new bound to the context ofcode-based cryptography, where guaranteed error rates are needed to achieve strong security levels.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/276599

End-to-end Simulations of Coded Transmissions in Space Links Affected by Solar Scintillation
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
Autore/i: Baldi, Marco; Chiaraluce, Franco; Maturo, Nicola; Ricciutelli, Giacomo; Ardito, Alessandro; Barbaglio, Francesco; Finocchiaro, Stefano; Simone, Lorenzo; Abello, Ricard; De Vicente, Javier; Mercolino, Mattia
Classificazione: 1 Contributo su Rivista
Abstract: In this paper coded space communication links impaired by solar scintillation are investigated, following a comprehensive end-to-end approach. With respect to baseband analyses, this allows for a more realistic modeling of actual communication links in these scenarios, though at the cost of longer simulation times and higher minimum values of the error rates assessable. The effect of solar scintillation on both signal amplitude and phase is studied, by considering also possible use of non-coherent demodulation to withstand phase synchronization impairments. The study allows optimizing some receiver parameters, such as the phase-locked loop bandwidth, in such a way as to face even critical contingency scenarios as well.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/273364

Lightweight Key Encapsulation Using LDPC Codes on FPGAs
IEEE TRANSACTIONS ON COMPUTERS
Autore/i: Hu, Jingwei; Baldi, Marco; Santini, Paolo; Zeng, Neng; Ling, San; Wang, Huaxiong
Classificazione: 1 Contributo su Rivista
Abstract: In this paper, we present a lightweight hardware design for a recently proposed quantum-safe key encapsulation mechanism based on QC-LDPC codes called LEDAkem, which has been admitted as a round-2 candidate to the NIST post-quantum standardization project. Existing implementations focus on high speed while few of them take into account area or power efficiency, which are particularly decisive for low-cost or power constrained IoT applications. The solution we propose aims at maximizing the metric of area efficiency by rotating the QC-LDPC code representations amongst the block RAMs in digit level. Moreover, optimized parallelized computing techniques, lazy accumulation and block partition are exploited to improve key decapsulation in terms of area and timing efficiency. We show for instance that our area-optimized implementation for 128-bit security requires 6.82× 1056.82×105 cycles and 2.26× 1062.26×106 cycles to encapsulate and decapsulate a shared secret, respectively. The area-optimized design uses only 39 slices (3 percent of the available logic) and 809 slices (39 percent of the available logic) for key encapsulation and key decapsulation respectively, on a small-size low-end Xilinx Spartan-6 FPGA.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/271010

Low-Lee-Density Parity-Check Codes
Proc. 2020 IEEE International Conference on Communications
Autore/i: Santini, P.; Battaglioni, M.; Chiaraluce, F.; Baldi, M.; Persichetti, E.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: We introduce a new family of linear block codes over Zq that we name low-Lee-density parity-check (LLDPC) codes. These codes, which are embedded with the Lee metric, are characterized by a parity-check matrix whose rows and columns have low Lee weight. We propose general constructions of LLDPC codes and devise an efficient iterative decoding algorithm for them, with complexity that grows linearly with the code length. We assess the error rate performance of these codes through numerical simulations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/282000

Off-line Correlator for Antenna Array Over Long Baselines
Proc. 8th ESA International Workshop on Tracking, Telemetry and Command Systems for Space
Autore/i: Ardito, A.; Maguire, P.; Marti, S.; Maturo, N.; Mercolino, M.; Quibus, L.; Vanhoenacker-Janvier, D.; Abellò, R.; Aroumont, A.; Baldi, M.; Barbaglio, F.; Chiaraluce, F.; Comoretto, G.; Finocchiaro, S.; Graziani, A.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/270641

Telecommunications in the ICT Age: From Research to Applications
The First Outstanding 50 Years of “Università Politecnica delle Marche”
Autore/i: Baldi, Marco; Cancellieri, Giovanni; Chiaraluce, Franco; DE SANTIS, Adelmo; Gambi, Ennio; Pierleoni, Paola
Editore: Springer
Luogo di pubblicazione: Cham
Classificazione: 2 Contributo in Volume
Abstract: The human society in the information age deeply relies on digital information processing, communication and storage. Photonic routing and switchingis expected to be exploited in future all-optical networks. Channel coding is needed in order to protect information against natural disturbances, and modern coding schemes are able to reach the ultimate limits predicted by Shannon. On the other hand, postquantum cryptography is necessary for assuring security against cyber attackers, possibly provided with quantum computers. Source coding, especially in video data compression, is recommended for optimizing the bandwidth usage. Spread spectrum systems can solve the problem of radio transmissions over common frequency bands. These technologies are of crucial importance for the evolution of networks and of the whole Internet, allowing people to interact each other and access information in the web. Nowadays, the conventional Internet of people has moved into the pervasive Internet of Things providing innovative services in a variety of application fields. In this respect, domotic systems, based on ambient and wearable sensors, appear of dramatic importance in the design of future assisted living protocols.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/273365

Theoretical Analysis and Implementation of Effective Receivers for Telecommand Space Links
Proc. 8th ESA International Workshop on Tracking, Telemetry and Command Systems for Space
Autore/i: Baldi, M.; Prata, R.; Simone, L.; Urrutia, C.; Bertinelli, M.; Chiaraluce, F.; Freire da Silva, P.; Garello, R.; Maturo, N.; Navarro, M.; Palomo, J. M.; Paolini, E.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/270642

Using Non-Binary LDPC and MDPC Codes in the McEliece Cryptosystem
Proc. AEIT 2019 International Annual Conference
Autore/i: Baldi, M.; Cancellieri, G.; Chiaraluce, F.; Edoardo, Persichetti; Santini, P.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/270640

Statistical and Machine Learning-Based Decision Techniques for Physical Layer Authentication
2019 IEEE Global Communications Conference (GLOBECOM)
Autore/i: Senigagliesi, Linda; Baldi, Marco; Gambi, Ennio
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/275253

NEXTRACK - Next Generation ESTRACK Uplink Services
Proc. 8th ESA International Workshop on Tracking, Telemetry and Command Systems for Space
Autore/i: Abellò, R.; Prata, R.; Santos Ugarte, L.; Simone, L.; Baldi, M.; Chiaraluce, F.; Fernandes, R.; Freire da Silva, P.; Garello, R.; Gelfusa, D.; Palomo, J. M.; Paolini, E.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/270643

Girth Properties of Time-Varying SC-LDPC Convolutional Codes
Proceedings 2019 IEEE ISIT
Autore/i: Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco; Lentmaier, Michael
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Time-varying spatially-coupled low-density paritycheck convolutional codes (SC-LDPC-CCs) exhibit excellent features, but their representation requires a very large number of parameters. On the other hand, the description of time-invariant SC-LDPC-CCs is very convenient and their error rate performance, though usually worse, is often satisfactory. In this paper we investigate the girth properties of these codes, showing that the time-invariant ones have some weaknesses, which can be compensated by introducing a small periodicity in the code. By considering periodically time-varying codes, we achieve considerable improvements in the girth properties using few more degrees of freedom with respect to the time-invariant case.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267824

Hard-decision iterative decoding of LDPC codes with bounded error rate
Proc. IEEE ICC 2019
Autore/i: Santini, Paolo; Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Differently from bounded-distance decoders used for algebraic codes, iterative decoders used for low-density parity-check (LDPC) codes are not characterized by a deterministic decoding radius. Therefore, the error rates of LDPC-coded transmissions are usually estimated heuristically through simulations.This is adequate for many applications like wireless communications, where a frame error rate (FER) in the order of 10^(-6) or higher is usually targeted. However, lower values of FER can barely be assessed through simulations, and this limits the use of LDPC codes in applications requiring a lower FER, like optical communications and code-based cryptography. In this paper we introduce and study a version of the classic bit flipping (BF) decoder for which we are able to devise and develop a theoretical characterization of the FER. In addition, we consider a two-iteration hard-decision decoder for LDPC codes derived from BF, and discuss its error rate performance. Our results are validated through numerical simulations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/266392

A finite regime analysis of information set decoding algorithms
ALGORITHMS
Autore/i: Baldi, M.; Barenghi, A.; Chiaraluce, F.; Pelosi, G.; Santini, P.
Classificazione: 1 Contributo su Rivista
Abstract: Decoding of random linear block codes has been long exploited as a computationally hard problem on which it is possible to build secure asymmetric cryptosystems. In particular, both correcting an error-affected codeword, and deriving the error vector corresponding to a given syndrome were proven to be equally difficult tasks. Since the pioneering work of Eugene Prange in the early 1960s, a significant research effort has been put into finding more efficient methods to solve the random code decoding problem through a family of algorithms known as information set decoding. The obtained improvements effectively reduce the overall complexity, which was shown to decrease asymptotically at each optimization, while remaining substantially exponential in the number of errors to be either found or corrected. In this work, we provide a comprehensive survey of the information set decoding techniques, providing finite regime temporal and spatial complexities for them. We exploit these formulas to assess the effectiveness of the asymptotic speedups obtained by the improved information set decoding techniques when working with code parameters relevant for cryptographic purposes. We also delineate computational complexities taking into account the achievable speedup via quantum computers and similarly assess such speedups in the finite regime. To provide practical grounding to the choice of cryptographically relevant parameters, we employ as our validation suite the ones chosen by cryptosystems admitted to the second round of the ongoing standardization initiative promoted by the US National Institute of Standards and Technology.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/270644

Resource allocation for secure Gaussian parallel relay channels with finite-length coding and discrete constellations
EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING
Autore/i: Senigagliesi, Linda; Baldi, Marco; Tomasin, Stefano
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272649

Sharing health data among general practitioners: The Nu.Sa. project
INTERNATIONAL JOURNAL OF MEDICAL INFORMATICS
Autore/i: Frontoni, Emanuele; Mancini, Adriano; Baldi, Marco; Paolanti, Marina; Moccia, Sara; Zingaretti, Primo; Landro, Vincenzo; Misericordia, Paolo
Classificazione: 1 Contributo su Rivista
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/266851

Code-based physical layer secret key generation in passive optical networks
AD HOC NETWORKS
Autore/i: Baldi, Marco; Chiaraluce, Franco; Incipini, Lorenzo; Ruffini, Marco
Classificazione: 1 Contributo su Rivista
Abstract: To guarantee secure transmissions is an important target of passive optical networks (PONs). Modern standards for PONs, however, impose the adoption of symmetric encryption algorithms in downstream but do not do the same in upstream, where the secret keys may be transmitted in clear. Because of non- ideal optical network components, this exposes the PON to the risk of eavesdropping. In this paper, a novel technique for securely generating and sharing secret keys in passive optical networks is proposed. It exploits randomness at the physical layer and key distillation based on coding techniques. The main attack strategies are considered and the design parameters of the proposed protocol are discussed, both in analytical terms and through numerical examples. The cost in terms of complexity with respect to standard approaches affected by possible vulnerabilities is also assessed.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/263398

Security of generalised Reed–Solomon code-based cryptosystems
IET INFORMATION SECURITY
Autore/i: Baldi, Marco; Chiaraluce, Franco; Rosenthal, Joachim; Santini, Paolo; Schipani, DAVIDE MOSE
Classificazione: 1 Contributo su Rivista
Abstract: In this study, the authors elaborate on a recently proposed variant of the public-key McEliece and Niederreiter cryptosystems using generalised Reed–Solomon (GRS) codes as private codes. The use of these codes brings known advantages in terms of public key size, but particular care is needed in the choice of parameters not to endanger the system security. In fact, the considered system exploits a strong disguising technique of the private code within the public code. However, it has recently been pointed out that some new attacks exist which may threaten some instances of such a system, therefore the choice of parameters needs to consider some further constraints compared to the original version. After outlining these constraints, the authors propose a new modification of the system achieving greater flexibility in the parameter choice. Moreover, the new system exhibits a lower complexity than the original GRS code-based system. Its very competitive features such as key size and encryption rate are highlighted with respect to classic systems.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/263712

Cryptanalysis of a One-Time Code-Based Digital Signature Scheme
Proc. 2019 IEEE ISIT
Autore/i: Santini, Paolo; Baldi, Marco; Chiaraluce, Franco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: We consider a one-time digital signature scheme recently proposed by Persichetti and show that a successful key recovery attack can be mounted with limited complexity. The attack we propose exploits a single signature intercepted by the attacker, and relies on a statistical analysis performed over such a signature, followed by information set decoding. We assess the attack complexity and show that a full recovery of the secret key can be performed with a work factor that is far below the claimed security level. The efficiency of the attack is motivated by the sparsity of the signature, which leads to a significant information leakage about the secret key.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/267825

Blind Physical Layer Authentication over Fading Wireless Channels through Machine Learning
2019 IEEE International Workshop on Information Forensics and Security (WIFS)
Autore/i: Senigagliesi, Linda; Cintioni, Lorenzo; Baldi, Marco; Gambi, Ennio
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The problem of determining the source of a message in a wireless communication link is challenging, especially for those systems in which cryptographic approaches are barely feasible due to limited resources. In this paper we consider a physical layer authentication protocol based on the characteristics of the communication channel and exploiting machine learning techniques to obtain authentication without needing any statistical knowledge of the channel from the authenticator. Different operational conditions are taken into account, considering a set of parallel channels affected by time-varying fading and assuming correlation between an opponent’s channel and the authenticator’s channel. Nearest Neighbor (NN) classification is used for authentication, and since the authenticator has no access to forged messages during the training phase, one-class NN classification algorithms are considered. We show that a good secrecy performance with a small training set may be achieved, allowing detection of an attacker with a very high probability in most of the cases. On the other hand, aiming at guaranteeing security even in the case of rapidly varying channels, these techniques prove to be quite conservative, and exhibit a high probability of refusing uncertain messages even when they come from the legitimate transmitter.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/276586

Analysis of reaction and timing attacks against cryptosystems based on sparse parity-check codes
Proc. CBC 2019
Autore/i: Santini, P.; Battaglioni, M.; Chiaraluce, F.; Baldi, M.
Editore: Springer Nature Switzerland, Cham
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper we study reaction and timing attacks against cryptosystems based on sparse parity-check codes, which encompass low-density parity-check (LDPC) codes and moderate-density parity-check (MDPC) codes. We show that the feasibility of these attacks is not strictly associated to the quasi-cyclic (QC) structure of the code but is related to the intrinsically probabilistic decoding of any sparse parity-check code. So, these attacks not only work against QC codes, but can be generalized to broader classes of codes. We provide a novel algorithm that, in the case of a QC code, allows recovering a larger amount of information than that retrievable through existing attacks and we use this algorithm to characterize new side-channel information leakages. We devise a theoretical model for the decoder that describes and justifies our results. Numerical simulations are provided that confirm the effectiveness of our approach.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269335

Efficient Search and Elimination of Harmful Objects for the Optimization of QC-SC-LDPC Codes
Proceedings 2019 GLOBECOM
Autore/i: Battaglioni, Massimo; Chiaraluce, Franco; Baldi, Marco; Mitchell, David G. M.
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: The error correction performance of low-density parity-check codes under iterative message-passing decoding is degraded by the presence of certain harmful objects existing in their Tanner graph representation. Depending on the context, such harmful objects are known as stopping sets, trapping sets, absorbing sets, or pseudocodewords. In this paper, we propose a general procedure, based on emph{edge spreading}, that enables the design of good quasi-cyclic spatially coupled low-density parity-check codes. These codes are derived from quasi-cyclic low-density parity-check (QC-LDPC) block codes and possess a significantly reduced multiplicity of harmful objects with respect to the original QC-LDPC block codes. The proposed procedure relies on a novel algorithm that greedily spans the search space of potential candidates to reduce the multiplicity of the target harmful objects. The effectiveness of the method is validated via examples and numerical computer simulations.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/272653

LEDAcrypt: QC-LDPC code-based cryptosystems with bounded decryption failure rate
Proc. CBC 2019
Autore/i: Baldi, Marco; Barenghi, Alessandro; Chiaraluce, Franco; Pelosi, Gerardo; Santini, Paolo
Editore: Springer Nature Switzerland, Cham
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: We consider the QC-LDPC code-based cryptosystems named LEDAcrypt, which are under consideration by NIST for the second round of the post-quantum cryptography standardization initiative. LEDAcrypt is the result of the merger of the key encapsulation mechanism LEDAkem and the public-key cryptosystem LEDApkc, which were submitted to the first round of the same competition. We provide a detailed quantification of the quantum and classical computational efforts needed to foil the cryptographic guarantees of these systems. To this end, we take into account the best known attacks that can be mounted against them employing both classical and quantum computers, and compare their computational complexities with the ones required to break AES, coherently with the NIST requirements. Assuming the original LEDAkem and LEDApkc parameters as a reference, we introduce an algorithmic optimization procedure to design new sets of parameters for LEDAcrypt. These novel sets match the security levels in the NIST call and make the C99 reference implementation of the systems exhibit significantly improved figures of merit, in terms of both running times and key sizes. As a further contribution, we develop a theoretical characterization of the decryption failure rate (DFR) of LEDAcrypt cryptosystems, which allows new instances of the systems with guaranteed low DFR to be designed. Such a characterization is crucial to withstand recent attacks exploiting the reactions of the legitimate recipient upon decrypting multiple ciphertexts with the same private key, and consequentially it is able to ensure a lifecycle of the corresponding key pairs which can be sufficient for the wide majority of practical purposes.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269334

Obtaining structured generator matrices for QC-LDPC codes
Proceedings 2019 AEIT International Annual Conference
Autore/i: Battaglioni, Massimo; Santini, Paolo; Baldi, Marco; Cancellieri, Giovanni
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper we propose an efficient and general method to obtain structured generator matrices for QC-LDPC codes. Moreover, we devote particular attention to the family of fully-connected monomial codes and perform a statistical analysis of their low-weight unavoidable codewords, whose weight gives an upper bound on their minimum distance.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/270283

Physical layer security over fading wiretap channels through classic coded transmissions with finite block length and discrete modulation
PHYSICAL COMMUNICATION
Autore/i: Baldi, M.; Maturo, N.; Ricciutelli, G.; Chiaraluce, F.
Classificazione: 1 Contributo su Rivista
Abstract: The chance to use existing coded transmission schemes for achieving some security at the physical layer besides reliability is of interest for many applications. In this paper, we assess the levels of physical layer security achievable by classic coding schemes over fading wiretap channels, taking into account the effects of finite block lengths and discrete modulations. In order to take these practical constraints into account, some previous works use the error rates experienced by legitimate receivers and eavesdroppers as reliability and security metrics, respectively. However, having a high error rate at the eavesdropper is a necessary but not a sufficient condition for security, thus we resort to more robust information theoretic security metrics for such a purpose. By focusing on mutual information security, we estimate the average number of attempts required by an attacker to recover the whole message in practical conditions and under outage constraints. Based on this metric, higher layer cryptographic protocols can be designed to achieve robust security built upon the physical layer. We obtain lower bounds on the wiretapper equivocation about the secret message, subject to some outage probability, and assess their tightness. We provide some examples considering classic coding and modulation techniques like extended Bose–Chaudhuri–Hocquenghem codes and convolutional codes with binary signaling.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269583

Analysis of the Block Error Probability of Concatenated Polar Code Ensembles
IEEE TRANSACTIONS ON COMMUNICATIONS
Autore/i: Ricciutelli, G.; Jerkovits, T.; Baldi, M.; Chiaraluce, F.; Liva, G.
Classificazione: 1 Contributo su Rivista
Abstract: In this paper, we provide an analysis of the performance of concatenation of polar codes with outer cyclic redundancy check (CRC) codes, separated by an interleaver, in the short and moderate block length regimes. The analysis addresses maximum likelihood decoding as a proxy to the code performance under successive cancellation list decoding. The analysis is carried out by introducing the concatenated polar code (CPC) ensembles, whose distance properties can be analyzed (for sufficiently short block lengths) by means of the uniform interleaver approach. At moderate block lengths, we resort to the Monte Carlo simulations. Results show that if the inner polar code possesses a low minimum distance and the outer CRC code has a sufficiently large amount of redundancy, then the choice of the outer code generator polynomial and the interleaver may yield to a large variability in the performance of the resulting CPC.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269628

Coded transmissions for space links affected by solar scintillation: Baseband analysis
INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS AND NETWORKING
Autore/i: Baldi, Marco; Chiaraluce, Franco; Maturo, Nicola; Ricciutelli, Giacomo; Ardito, Alessandro; Barbaglio, Francesco; Finocchiaro, Stefano; Simone, Lorenzo; Abelló, Ricard; De Vicente, Javier; Mercolino, Mattia
Classificazione: 1 Contributo su Rivista
Abstract: Summary A thorough analysis of the behavior of error-correcting codes over space links affected by solar scintillation is presented. The relevant channel parameters are fixed through the development of a model based on real missions' data. Both telecommand and telemetry links are considered in fast and slow fading conditions. Besides classical coherent modulation schemes, the possibility to use noncoherent modulation schemes is considered, to eliminate the problem of phase tracking. For the case of channels with very slow fading, the use of external interleavers or erasure coding is proposed to cope with error bursts.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/263392

A data-driven approach to cyber risk assessment
SECURITY AND COMMUNICATION NETWORKS
Autore/i: Santini, P.; Gottardi, G.; Baldi, M.; Chiaraluce, F.
Classificazione: 1 Contributo su Rivista
Abstract: Cyber risk assessment requires defined and objective methodologies; otherwise, its results cannot be considered reliable. ­e lack of quantitative data can be dangerous: if the assessment is entirely qualitative, subjectivity will loom large in the process. Too much subjectivity in the risk assessment process can weaken the credibility of the assessment results and compromise risk management programs. On the other hand, obtaining a sufficiently large amount of quantitative data allowing reliable extrapolations and previsions is often hard or even unfeasible. In this paper, we propose and study a quantitative methodology to assess a potential annualized economic loss risk of a company. In particular, our approach only relies on aggregated empirical data, which can be obtained from several sources. We also describe how the method can be applied to real companies, in order to customize the initial data and obtain reliable and specific risk assessments.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/269582

Hindering reaction attacks by using monomial codes in the McEliece cryptosystem
Proc. IEEE ISIT 2018
Autore/i: Santini, Paolo; Baldi, Marco; Cancellieri, Giovanni; Chiaraluce, Franco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: In this paper we study recent reaction attacks against QC-LDPC and QC-MDPC code-based cryptosystems, which allow an opponent to recover the private parity-check matrix through its distance spectrum by observing a sufficiently high number of decryption failures. We consider a special class of codes, known as monomial codes, to form private keys with the desirable property of having a unique and complete distance spectrum. We verify that for these codes the problem of recovering the secret key from the distance spectrum is equivalent to that of finding cliques in a graph, and use this equivalence to prove that current reaction attacks are not applicable when codes of this type are used in the McEliece cryptosystem.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/258706

LEDAkem: A Post-quantum Key Encapsulation Mechanism Based on QC-LDPC Codes
Post-Quantum Cryptography. PQCrypto 2018.
Autore/i: Baldi, Marco; Barenghi, Alessandro; Chiaraluce, Franco; Pelosi, Gerardo; Santini, Paolo
Editore: Springer
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: This work presents a new code-based key encapsulation mechanism (KEM) called LEDAkem. It is built on the Niederreiter cryptosystem and relies on quasi-cyclic low-density parity-check codes as secret codes, providing high decoding speeds and compact keypairs. LEDAkem uses ephemeral keys to foil known statistical attacks, and takes advantage of a new decoding algorithm that provides faster decoding than the classical bit-flipping decoder commonly adopted in this kind of systems. The main attacks against LEDAkem are investigated, taking into account quantum speedups. Some instances of LEDAkem are designed to achieve different security levels against classical and quantum computers. Some performance figures obtained through an efficient C99 implementation of LEDAkem are provided.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/257853

Efficient search of compact QC-LDPC and SC-LDPC convolutional codes with large girth
IEEE COMMUNICATIONS LETTERS
Autore/i: Tadayon, Mohammad H.; Tasdighi, Alireza; Battaglioni, Massimo; Baldi, Marco; Chiaraluce, Franco
Classificazione: 1 Contributo su Rivista
Abstract: We propose a low-complexity method to find quasi-cyclic low-density parity-check block codes with girth 10 or 12 and length shorter than those designed through classical approaches. The method is extended to time-invariant spatially coupled low-density parity-check convolutional codes, permitting to achieve small syndrome former constraint lengths. Several numerical examples are given to show its effectiveness.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/257854

Assessing and Countering Reaction Attacks Against Post-Quantum Public-Key Cryptosystems Based on QC-LDPC Codes
Cryptology and Network Security
Autore/i: Santini, Paolo; Baldi, Marco; Chiaraluce, Franco
Editore: Springer
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/260223

Connections between low-weight codewords and cycles in spatially coupled LDPC convolutional codes
IEEE TRANSACTIONS ON COMMUNICATIONS
Autore/i: Battaglioni, Massimo; Baldi, Marco; Cancellieri, Giovanni
Classificazione: 1 Contributo su Rivista
Abstract: In this paper time-invariant spatially coupled low-density parity-check convolutional codes (SC-LDPC-CCs) are considered, and the connections existing between their low-weight codewords and cycles in their Tanner graphs are studied. Using the polynomial representation of these codes, we show that parity-check matrices having columns with weight ≥ 2 can be analyzed considering a certain number of parity-check sub-matrices having regular columns with weight 2. These sub-matrices are associated to cycles in the code Tanner graph and define as many codes we denote as component codes. Based on this observation, we find that codewords of the main code can be expressed as a combination of codewords of the component codes. The design of codes free of codewords up to a certain weight is also addressed. We show that low-weight codewords in the main code can be avoided by removing some types of cycles in its Tanner graph. Our design approach is applied to some well known ensembles of SC-LDPC-CCs to prove its effectiveness.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/257855

Compact QC-LDPC Block and SC-LDPC Convolutional Codes for Low-Latency Communications
Proc. IEEE 29th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC 2018)
Autore/i: Battaglioni, Massimo; Tasdighi, Alireza; Baldi, Marco; Tadayon, Mohammad H.; Chiaraluce, Franco
Classificazione: 4 Contributo in Atti di Convegno (Proceeding)
Abstract: Low decoding latency and complexity are two important requirements of channel codes used in many applications, like machine-to-machine communications. In this paper, we show how these requirements can be fulfilled by using some special quasi-cyclic low-density parity-check block codes and spatially coupled low-density parity-check convolutional codes that we denote as compact. They are defined by parity-check matrices designed according to a recent approach based on sequentially multiplied columns. This method allows obtaining codes with girth up to 12. Many numerical examples of practical codes are provided.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259763

Interleaver design for short concatenated codes
IEEE COMMUNICATIONS LETTERS
Autore/i: Ricciutelli, Giacomo; Baldi, Marco; Chiaraluce, Franco
Classificazione: 1 Contributo su Rivista
Abstract: The choice of the interleaver may significantly affect the performance of short codes when they are used in serial concatenation. By focusing on the minimum distance of the overall concatenated code, we propose an algorithmic method for the design of good interleavers. As a valuable example of application, we consider the case of polar codes concatenated with cyclic redundancy check codes. For these codes, the method we propose is compared with classical approaches based on random searches to assess its advantages, which are also confirmed through examples of practical coded transmissions over the binary erasure channel.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/259762

Design and Analysis of Time-Invariant SC-LDPC Convolutional Codes with Small Constraint Length
IEEE TRANSACTIONS ON COMMUNICATIONS
Autore/i: Battaglioni, Massimo; Tasdighi, Alireza; Cancellieri, Giovanni; Chiaraluce, Franco; Baldi, Marco
Classificazione: 1 Contributo su Rivista
Abstract: In this paper, we deal with time-invariant spatially coupled low-density parity-check convolutional codes (SC-LDPCCCs). Classic design approaches usually start from quasi-cyclic low-density parity-check (QC-LDPC) block codes and exploit suitable unwrapping procedures to obtain SC-LDPC-CCs. We show that the direct design of the SC-LDPC-CCs syndrome former matrix or, equivalently, the symbolic parity-check matrix, leads to codes with smaller syndrome former constraint lengths with respect to the best solutions available in the literature. We provide theoretical lower bounds on the syndrome former constraint length for the most relevant families of SC-LDPCCCs, under constraints on the minimum length of cycles in their Tanner graphs. We also propose new code design techniques that approach or achieve such theoretical limits.
Scheda della pubblicazione: https://iris.univpm.it/handle/11566/251878