We present a chosen-ciphertext attack against both NICE cryptosystems. These two cryptosystems are based on computations in the class group of non-maximal imaginary orders. More pr...
A cryptanalysis is given of a MAC proposal presented at CRYPTO 2003 by Cary and Venkatesan. A nice feature of the CaryVenkatesan MAC is that a lower bound on its security can be pr...
In 2002, Murphy and Robshaw introduced an extension BES of AES and argued this could compromise the security of AES. We introduce here two block-ciphers CES and Big-BES that are so...