Study on Length of Hash-Values for Digital Signature Schemes Based on Zero-Knowledge
Pingshui Wang · Computer Technology and Development · 2007
Hash function has already been applied in all kinds of digital signature schemes.In digital signature schemes based on the zero-knowledge concept,it has been claimed that the length of Hash-values could be as short as 64 or 72 bits for the security of 2-64or 2-72.Shows that signature schemes with such short Hash-values cannot achieve the stated security levels,due to the birthday attack by the signer.A simple modification is also presented,where the stated security levels can be obtained without increase of computational load.