SAT-based cryptanalysis of ACORN

The CAESAR competition aims to provide a portfolio of authenticated encryption algorithms. SAT solvers represent powerful tools to verify automatically and efficiently (among others) the confidentiality and the authenticity of information claimed by cryptographic primitives. In this work, we study the security of the CAESAR candidate Acorn against a SAT-based cryptanalysis. We provide the first practical and efficient attacks on the first and the last versions of Acorn. More precisely, we achieve state recovery, key recovery, state collision as well as forgery attacks. All our results demonstrate the usefulness of SAT solvers to cryptanalyse all the candidates of the CAESAR competition, thereby accelerating the “test of time”.