Mgr. Olha Jurečková


Master theses

Randomness Testing of the Elephant Stream Cipher

Jiří Hájek
Master thesis
Mgr. Olha Jurečková
Mgr. Tomáš Rabas
This thesis presents an analysis of the randomness of the Dumbo instance of the Elephant cipher. The author used various statistical tests, including tests from NIST's Statistical Test Suite, the d-monomial test and cube testers. The results showed that Dumbo passed the majority of the tests from NIST's STS with only a few failures that were not considered significant. The d-monomial test also showed no bias in any particular keystream bit. The most significant finding of this work was the discovery that Dumbo had difficulty passing the balance test from the family of cube testers as some keystream bits only passed every other test case and many cubes resulted in a pass rate of around 20 %. The thesis concludes that Dumbo demonstrates good randomness properties overall but highlights the need for further investigation of this cipher to identify any potential major issues.