Cryptographic password obfuscation

Abstract

We consider cryptographic program obfuscation of point functions (i.e., functions parameterized by a secret s that, on input a string x, return 1 if x = s and 0 otherwise). We achieve the following notable results: (1) the first efficient point function obfuscator for arbitrarily large as well as very short secrets, provable without random oracle assumptions; (2) the first efficient and provably-secure (under the existence of one-way permutations or block ciphers that have no theoretical attack faster than exhaustive key search) real-life applications built on top of these obfuscators, such as: (a) entity authentication via password verification; (b) entity authentication via passphrase verification; and (c) password management for multi-site entity authentication.