Abstract

A oneway hashing algorithm is a deterministic algorithm that compresses an arbitrary long message into a value of specified length. The output value represents the fingerprint or digest of the message. A cryptographically useful property of a oneway hashing algorithm is that it is infeasible to find two distinct messages that have the same fingerprint. This paper proposes a oneway hashing algorithm called HAVAL. HAVAL compresses a message of arbitrary length into a fingerprint of 128, 160, 192, 224 or 256 bits. In addition, HAVAL has a parameter that controls the number of passes a message block (of 1024 bits) is processed. A message block can be processed in 3, 4 or 5 passes. By combining output length with pass, we can provide fifteen (15) choices for practical applications where different levels of security are required. The algorithm is very efficient and particularly suited for 32bit computers which predominate the current workstation market. Experiments show that HAVAL is 60% faster than MD5 when 3 passes are required, 15% faster than MD5 when 4 passes are required, and as fast as MD5 when full 5 passes are required. It is conjectured that finding two collision messages requires the order of 2n/2 operations, where n is the number of bits in a fingerprint.