1. The MD4 message digest algorithm;Rivest,1991
2. R.L. Rivest, The MD5 message digest algorithm, request for comments (RFC) 1321 internet activities board internet privacy task force, April, 1992.
3. FIPS180, Secure hash standard, federal information processing standard (FIPS), publication 180, National Institute of Standards and Technology, US Department of Commerce, Washington D.C., May 1993.
4. Hash functions based on block ciphers A synthetic approach;Preneel,1994
5. B.O. Brachtl, D. Coppersmith, M.M. Hyden, S.M. Matyas, C.H. Meyer, J. Oseas, S. Pilpel, M. Schilling, Data authentication using modification detection codes based on a public one way encryption function, U.S. Patent Number 4,908,861, March 13, 1990.