One view of digital signatures is that MACs and MDs may be sufficient when:
1. the evidence is logged or otherwise kept by several parties, and 2. there exists sufficient legal clout to discourage tampering. An example of 2. above would be the relatively new Sarbanes-Oxley Act in the US. Section 1102 of that act adjusts the US Code to add this little gem: Whoever corruptly-- "(1) alters, destroys, mutilates, or conceals a record, document, or other object, or attempts to do so, with the intent to impair the object's integrity or availability for use in an official proceeding; or "(2) otherwise obstructs, influences, or impedes any official proceeding, or attempts to do so, shall be fined under this title or imprisoned not more than 20 years, or both.". http://www.law.uc.edu/CCL/SOact/sec1102.html Can we surmise that a digital record with an MD attached and logged would fall within "object" ? Having a full scale public key based signature implementation would always be "better" in pure terms of systems closure, but if a PKI costs too much, and a company was covered as above, using cheaper solutions might work out. Comments? iang --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]