Decryption Despite Errors: Presentation from CB-Crypto Workshop 2021

Upload of my presentation given during the cb-crypto workshop on code based cryptography 2021. Slides & Paper Draft: https://github.com/koraa/decryption-despite-errors This talk introduces the notion of decryption despite errors: ciphers that remain secure in the presence of adversarial errors in the cipher text without the requirement of discarding the message entirely. Definitions of and fundamental limits of security under these constraints are presented. Informally, it should be infeasible for an attacker to do any better than raising the (random) noise level in the plain text in the attempt to forge messages. More formally, asymptotic infeasibility of distinguishing the decryption of two challenger-chosen error-patterns (bit flips) with the same number of errors must be demonstrated for security. Security against fuzzing is formalized. The outline of a construction that operates as a mode for a pseudo random function is presented; the construction is based on multiple rounds of an error correcting code and interleaver, both randomized using the PRF generated key stream.