The random number sequence is mandatory for a good cryptography, which also has to fulfill all the statistical test criteria. The unconformity to the test criteria is a weakness for a random sequence method. We develop discrete time chaos (DTC) based random number generator using the SHA-256 hash function as post processing. The message on the hash function is obtained from the clock source LFSR process, and the DTC output determines the initial values of the hash function, which are limited by a minimum value. The tests performed show that the output sequences generated by the proposed method have high entropy value, uncorrelated values and addition to pass all NIST 800-22 statistical test suites.

discrete time chaos (DTC), LFSR-based hash function, random number generator.