Construction of Highly Nonlinear Resilient Boolean Functions Satisfying Strict Avalanche Criterion

A method is proposed to construct resilient Boolean functions on $n$ variables ($n$ even) satisfying strict avalanche criterion (SAC) with nonlinearity $>2^{n-1}-2^{n/2}$. A large class of cryptographic Boolean functions which were not known earlier are obtained

Forgery Attacks on Chang et al.\u27s signature scheme with message recovery

It is found that Chang et al.\u27s signature scheme with message recovery is not as secure as they claimed, in fact. In this letter, two forgery attacks is proposed to show that the signature can be forged on any uncontrolled messages. To overcome these attacks, the one-way hash functions and the message redundancy schemes may be still used