In this paper, security analysis of block ciphers with key length greater than block length is proposed. When key length is significantly greater than block length and the statistical distribution of cipher system is like a uniform distribution, there are more than one key which map fixed input to fixed output. If a block cipher designed sufficiently random, it is expected that the key space ca...

We propose a novel methodology to design Block Cipher functions. This methodology is illustrated with the design of a specific block cipher function Maya. Our design philosophy is to derive the SBoxes themselves from the secret key. This makes breaking any round function equivalent to guessing all the key-bits. Advantages of our design include much larger key sizes in relation to the block size...

In [Mur00], Murphy raises questions about key separation in Twofish. We discuss this property of the Twofish key schedule, and compare it with other block ciphers. While every block cipher has this property in some abstract sense, the specific structure of Twofish makes it an interesting property to consider. We explain why we don’t believe this property leads to any interesting attacks on Twof...

We propose a generalisation of Paillier’s probabilistic public key system, in which the expansion factor is reduced and which allows to adjust the block length of the scheme even after the public key has been fixed, without loosing the homomorphic property. We show that the generalisation is as secure as Paillier’s original system. We construct a threshold variant of the generalised scheme as w...

This paper generalizes previous optimal upper bounds on the minimum Euclidean distance for phase shift keying (PSK) block codes, that are explicit in three parameters: alphabet size, block length and code size. The bounds are primarily generalized from codes over symmetric PSK to codes over asymmetric PSK and also to general alphabet size. Furthermore, block codes are optimized in the presence ...

We present a new block cipher LED. While dedicated to compact hardware implementation, and offering the smallest silicon footprint among comparable block ciphers, the cipher has been designed to simultaneously tackle three additional goals. First, we explore the role of an ultra-light (in fact non-existent) key schedule. Second, we consider the resistance of ciphers, and LED in particular, to r...