Someone abused "Frederick B. Cohen"'s reputation by making him write :
there is no way to do this in practice because as RSA-based signatures are actually implemented only hashes are signed. This is done exactly to prevent this and similar attacks. And how secure is the hash? By design choice, "Very secure"...("the difficulty of coming up with any message having a given message digest is on the order of 2^128 operationssee end") It it possible to create values that will hash to each prime (or something else that does the job)? No. Is the hash something we can figure a way to precompute using massively parallel processing so that we can then provide a set of codes which will produce the desired results? (etc.) No.
Why wouldn't you try to answer the questions yourself before mailing random thought ? see RFC1321 The MD5 Message-Digest Algorithm and numerous reviews... Maybe I was being just "tested" and should not have replied :/ dl -- Laurent Demailly * http://hplyot.obspm.fr/~dl/ * Linux|PGP|Gnu|Tcl|... Freedom Prime#1: cent cinq mille cent cinq milliards cent cinq mille cent soixante sept Uzi security Marxist NSA ammunition NORAD FSF