TestU01 and Practrand: Tools for a randomness evaluation for famous multimedia ciphers

Abstract

New dangerous attacks have arisen as we witness the current evolution of digital data. Connecting devices, vehicles, even our own bodies to the Internet have generated enormous amounts of data that need to be secured. New security solutions and ciphers are being proposed taking into consideration all the limitations in the devices used in today’s technologies. However, different factors have to be taken into consideration to prove the reliability of any cipher. One of these criteria is the randomness of the ciphered output. Usually, randomness tests are used to prove the efficiency of Pseudo Random Number Generators- PRNGs, and they are not considered in the test suite for cryptographic algorithms. This paper proposes using the well known tools Practrand (Doty-Humphrey 2010) and TestU01 (L’Ecuyer and Simard, ACM Trans Math Soft (TOMS) 33(4):22, 2007) to test the randomness criteria for any new/old symmetric cipher. To show our cryptographic point of view, several well known ciphers were tested by these tools. Some of them failed these tests and did not meet the desired security requirements and the sufficient statistical immunity. In fact, this paper shows that these ciphers do not generate enough randomness making them vulnerable to different kinds of attacks which reinforces our proposal.