Alladi Ramakrishnan Hall

Avalanche effect by local interactions

Celestine P Lawrence

IMSc, Chennai

The avalanche effect is a desirable property for Boolean functions in
cryptography. For a multi-input single-output Boolean function, the
strict-avalanche criterion (SAC) requires that the output bit changes with
a 50% probability upon flipping any input bit. We investigate Boolean
functions where an input array is transformed to an output value by a
series of cellular automaton (CA) rules. We find that there is an abundance
of strong avalanche effect among CAs with just next-nearest neighbor
interactions. This work is an improvement over the knowledge that the
Rule-30 CA is useful for cryptography, and can help in engineering hardware
that is simple, energy-efficient, and ultra-fast for one-time pad
encryption.