María Naya-Plasencia

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The need for lightweight (that is, compact, low-power, low-energy) cryptographic hash functions has been repeatedly expressed by professionals, notably to implement cryptographic protocols in RFID technology. At the time of writing, however, no algorithm exists that provides satisfactory security and performance. The ongoing SHA-3 Competition will not help,(More)
Non-linear feedback shift registers are widely used in lightweight cryptographic primitives. For such constructions we propose a general analysis technique based on differential cryptanalysis. The essential idea is to identify conditions on the internal state to obtain a deterministic differential characteristic for a large number of rounds. Depending on(More)
Impossible differential cryptanalysis has shown to be a very powerful form of cryptanalysis against block ciphers. These attacks, even if extensively used, remain not fully understood because of their high technicality. Indeed, numerous are the applications where mistakes have been discovered or where the attacks lack optimality. This paper aims in a first(More)
iii Abstract The National Institute of Standards and Technology (NIST) opened a public competition on November 2, 2007, to develop a new cryptographic hash algorithm – SHA-3, which will augment the hash algorithms specified in the Federal Information Processing Standard (FIPS) 180-4, Secure Hash Standard (SHS). The competition was NIST's response to(More)
The design and analysis of lightweight block ciphers has been a very active research area over the last couple of years, with many innovative proposals trying to optimize different performance figures. However, since these block ciphers are dedicated to low-cost embedded devices, their implementation is also a typical target for side-channel adversaries. As(More)
Bernstein’s CubeHash is a hash function family that includes four functions submitted to the NIST Hash Competition. A CubeHash function is parametrized by a number of rounds r, a block byte size b, and a digest bit length h (the compression function makes r rounds, while the finalization function makes 10r rounds). The 1024-bit internal state of CubeHash is(More)
KLEIN is a family of lightweight block ciphers presented at RFIDSec 2011 that combines a 4-bit Sbox with Rijndael’s byte-oriented MixColumn. This approach allows compact implementations of KLEIN in both low-end software and hardware. This paper shows that interactions between those two components lead to the existence of differentials of unexpectedly high(More)
This paper presents a new generic technique, named sieve-in-the-middle, which improves meet-in-the-middle attacks in the sense that it provides an attack on a higher number of rounds. Instead of selecting the key candidates by searching for a collision in an intermediate state which can be computed forwards and backwards, we here look for the existence of(More)