Author: Karel Kubicek
Abstract: Analysing cryptographic functions usually requires extensive work of a skilled cryptanalyst. However, some automation is possible, e.g., by using randomness testing batteries such as NIST STS or Dieharder. Yet such tests are limited to predefined test patterns. However, there is a new approach – EACirc is a novel randomness testing framework based on finding a distinguisher for a given cipher output. In this work, we use EACirc to analyse the outputs of Tiny Encryption Algorithm (TEA). TEA was previously used with genetic algorithms for evolution of bit masks used for restriction of cipher input. Instead of evolving bit masks, we create a software circuit applicable as a distinguisher for limited-round TEA (up to 4 rounds). Results of EACirc are also compared to the standard statistical batteries.