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Publications

Publications by HASLab

2025

Specification of paraconsistent transition systems, revisited

Authors
Cunha, J; Madeira, A; Barbosa, LS;

Publication
SCIENCE OF COMPUTER PROGRAMMING

Abstract
The need for more flexible and robust models to reason about systems in the presence of conflicting information is becoming more and more relevant in different contexts. This has prompted the introduction of paraconsistent transition systems, where transitions are characterized by two pairs of weights: one representing the evidence that the transition effectively occurs and the other its absence. Such a pair of weights can express scenarios of vagueness and inconsistency. . This paper establishes a foundation for a compositional and structured specification approach of paraconsistent transition systems, framed as paraconsistent institution. . The proposed methodology follows the stepwise implementation process outlined by Sannella and Tarlecki.

2025

Formally Verified Correctness Bounds for Lattice-Based Cryptography

Authors
Barbosa, M; Kannwischer, MJ; Lim, TH; Schwabe, P; Strub, PY;

Publication
PROCEEDINGS OF THE 2025 ACM SIGSAC CONFERENCE ON COMPUTER AND COMMUNICATIONS SECURITY, CCS 2025

Abstract
Decryption errors play a crucial role in the security of KEMs based on Fujisaki-Okamoto because the concrete security guarantees provided by this transformation directly depend on the probability of such an event being bounded by a small real number. In this paper we present an approach to formally verify the claims of statistical probabilistic bounds for incorrect decryption in lattice-based KEM constructions. Our main motivating example is the PKE encryption scheme underlying ML-KEM. We formalize the statistical event that is used in the literature to heuristically approximate ML-KEM decryption errors and confirm that the upper bounds given in the literature for this event are correct. We consider FrodoKEM as an additional example, to demonstrate the wider applicability of the approach and the verification of a correctness bound without heuristic approximations. We also discuss other (non-approximate) approaches to bounding the probability of ML-KEM decryption.

2025

Privacy and Security of FIDO2 Revisited

Authors
Barbosa, M; Boldyreva, A; Chen, S; Cheng, K; Esquível, L;

Publication
Proc. Priv. Enhancing Technol.

Abstract

2025

Tempo: ML-KEM to PAKE Compiler Resilient to Timing Attacks

Authors
Arriaga, A; Barbosa, M; Jarecki, S;

Publication
IACR Cryptol. ePrint Arch.

Abstract

2025

Revisiting the Security and Privacy of FIDO2

Authors
Barbosa, M; Boldyreva, A; Chen, S; Cheng, K; Esquível, L;

Publication
IACR Cryptol. ePrint Arch.

Abstract

2025

NoIC: PAKE from KEM without Ideal Ciphers

Authors
Arriaga, A; Barbosa, M; Jarecki, S;

Publication
IACR Cryptol. ePrint Arch.

Abstract

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