Serpent and Smartcards

Filtered Nonlinear Cryptanalysis of Reduced-Round Serpent, and the Wrong-Key Randomization Hypothesis

We present a deterministic algorithm to find nonlinear S-box approximations, and a new nonlinear cryptanalytic technique; the “filtered” nonlinear attack, which achieves the lowest data complexity of any known-plaintext attack on reduced-round Serpent so far. We demonstrate that the Wrong-Key Randomization Hypothesis is not entirely valid for attacks on reduced-round Serpent which rely on linea...

On Algebraic Relations of Serpent S-Boxes

Serpent is a 128-bit block cipher designed by Ross Anderson, Eli Biham and Lars Knudsen as a candidate for the Advanced Encryption Standard (AES). It was a finalist in the AES competition. The winner, Rijndael, got 86 votes at the last AES conference while Serpent got 59 votes [1]. The designers of Serpent claim that Serpent is more secure than Rijndael.In this paper we have observed that the n...

The Case for Serpent

Serpent should be chosen because it is the most secure of the AES finalists. Not only does it have ample safety margin, but its simple structure enables us to be sure that none of the currently known attacks will work. It is also simple to check that an implementation is correct. Although Serpent is not as fast as the other finalists on the 200 MHz Pentium machine used for round 1 benchmarking,...

A Differential-Linear Attack on 12-Round Serpent

Serpent is an SP Network block cipher submitted to the AES competition and chosen as one of its five finalists. The security of Serpent is widely acknowledged, especially as the best known attack so far is a differential-linear attack on only 11 rounds out of the 32 rounds of the cipher. In this paper we introduce a more accurate analysis of the differentiallinear attack on 11-round Serpent. Th...

Serpent: A Flexible Block Cipher With Maximum Assurance