Which Standard Crytographic Hash Algorithms Are Secure?
There is no good, simple answer to this question. Feasible – though expensive – attacks on MD5 have been made public. Similar weaknesses have been found in the SHA family of hashes though practical attacks are not yet publically known. However, longer hash sizes offer considerable protection. So, larger members of the SHA family still look likely to be secure enough for a number of years. RIPE has not been as well studied as either SHA or MD5. It is likely to offer no more security than SHA. SHA512 is the strongest well studied widely used cryptographic hash. It is therefore the best recommendation until SHA3 is available.
