On a construction of stream-cipher-based hash functions

Hash functions using stream ciphers as components perform fast on a variety of platforms. However, the security and the design policy of stream-cipher-based hash functions (SCHs) have not yet been studied sufficiently. In this paper, we analyze its design criteria based on a ideal function of SCHs. First, we show that attacks against a stream cipher can also be threats against SCHs. Then we discuss the security on each phase of SCH; message injection, blank rounds, and hash generation with this function. Finally we derive the necessary conditions on the stream cipher function for an SCH to be secure.