International Association for Cryptologic Research
The authors introduce counter-cryptanalysis as a new paradigm for strengthening weak cryptographic primitives against cryptanalytic attacks. Redesigning a weak primitive to more strongly resist cryptanalytic techniques will unavoidably break backwards compatibility. Instead, counter-cryptanalysis exploits unavoidable anomalies introduced by cryptanalytic attacks to detect and block cryptanalytic attacks while maintaining full backwards compatibility. Counter-cryptanalysis in principle enables the continued secure use of weak cryptographic primitives. Furthermore, they present the first example of counter-cryptanalysis, namely the efficient detection whether any given single message has been constructed - together with an unknown sibling message - using a cryptanalytic collision attack on MD5 or SHA-1.