Provably Solving the Hidden Subset Sum Problem via Statistical Learning

in Mathematical Cryptology (2022, March), 1

At Crypto ’99, Nguyen and Stern described a lattice based algorithm for solving the hidden subset sum problem, a variant of the classical subset sum problem where the n weights are also hidden. As an ... [more ▼]

At Crypto ’99, Nguyen and Stern described a lattice based algorithm for solving the hidden subset sum problem, a variant of the classical subset sum problem where the n weights are also hidden. As an application, they showed how to break the Boyko et al. fast generator of random pairs (x, g x(mod p)). The Nguyen-Stern algorithm works quite well in practice for moderate values of n, but its complexity is exponential in n. A polynomial-time variant was recently described at Crypto 2020, based on a multivariate technique, but the approach is heuristic only. In this paper, we describe a proven polynomial-time algorithm for solving the hidden subset-sum problem, based on statistical learning. In addition, we show that the statistical approach is also quite efficient in practice: using the FastICA algorithm, we can reach n = 250 in reasonable time. [less ▲]

Simultaneous Diagonalization of Incomplete Matrices and Applications

in Proceedings of the Fourteenth Algorithmic Number Theory Symposium (ANTS-XIV), edited by Steven Galbraith, Open Book Series 4, Mathematical Sciences Publishers, Berkeley, 2020 (2020, December)

We consider the problem of recovering the entries of diagonal matrices {U_a}_a for a = 1, . . . , t from multiple “incomplete” samples {W_a}_a of the form W_a = P U_a Q, where P and Q are unknown matrices ... [more ▼]

We consider the problem of recovering the entries of diagonal matrices {U_a}_a for a = 1, . . . , t from multiple “incomplete” samples {W_a}_a of the form W_a = P U_a Q, where P and Q are unknown matrices of low rank. We devise practical algorithms for this problem depending on the ranks of P and Q. This problem finds its motivation in cryptanalysis: we show how to significantly improve previous algorithms for solving the approximate common divisor problem and breaking CLT13 cryptographic multilinear maps. [less ▲]

Side-Channel Masking with Pseudo-Random Generator

in Eurocrypt 2020 (2020)

Cryptanalysis of CLT13 Multilinear Maps with Independent Slots

Speeches/Talks (2019)

Improved Cryptanalysis of the AJPS Mersenne Based Cryptosystem

in Journal of Mathematical Cryptology (2019)

At Crypto 2018, Aggarwal, Joux, Prakash and Santha (AJPS) described a new public-key encryption scheme based on Mersenne numbers. Shortly after the publication of the cryptosystem, Beunardeau et al ... [more ▼]

At Crypto 2018, Aggarwal, Joux, Prakash and Santha (AJPS) described a new public-key encryption scheme based on Mersenne numbers. Shortly after the publication of the cryptosystem, Beunardeau et al. described an attack with complexity O(2^(2h)). In this paper, we describe an improvedattack with complexity O(2^(1.75h)) . [less ▲]

High-Order Conversion from Boolean to Arithmetic Masking

in Proceedings of CHES 2017 (2017, September)

Faster Evaluation of SBoxes via Common Shares

in Proceedings of CHES 2016 (2016)

Cryptanalysis of GGH15 Multilinear Maps

in Proceedings of Crypto 2016 (2016)

New Multilinear Maps over the Integers

in Proceedings of Crypto 2015 (2015)

Secure Conversion between Boolean and Arithmetic Masking of Any Order

in Batina, Lejla; Robshaw, Matthew (Eds.) Cryptographic Hardware and Embedded Systems - CHES 2014, 16th International Workshop, Busan, South Korea, September 23-26, 2014. Proceedings (2014, September)