Chaotic Integrity Check Value

Abstract

Chaotic cryptography is slowly emerging as a subfield of cryptography. Many encryption algorithms, secure hash functions and random number generators have been proposed in the literature which are based on well-known chaotic functions. Chaotic keyed hash functions are proposed in the literature but have not been analysed for integrity check value purpose in the literature. We propose a keyed chaotic hash function based on parametrized family of logistic and tent maps and develop a message authentication code (MAC) which outputs a 128 bit message digest(MD).The keyed hash function is designed such that it is resistant to preimage and second preimage attacks. The chaotic hash functions proposed in the literature use a multitude of chaotic maps and we show in this paper that using two chaotic maps judiciously achieves a secure keyed hash function. The proposed keyed hash function is analysed for its sensitivity to the two secret keys that of initial value as well as the parameter value of the family of functions. Experiments in which as the secret keys are infinitesimally changed, the hash value obtained is shown to have nearly 50% of the bits different from the original MD. Further similar experiments are repeated with MD truncated to the first 96 bits, which is the default length for authentication data field in IPSec authentication header and encapsulating security payload. Once again the confusion is shown to be very close to 50%.