For example, it's probably a real bad idea to replace DES with something commonly called RC4. The former has been under public scrutiny for years, the later still has not formally emerged from the shroud of trade secret. The keyed MD5 responses also don't inspire confidence.
I disagree. Basically Simon simply has to stick in some parameters so that the crypto alg can change with time. There should be slots for the following algs :- Symmetric cipher IDEA, RC4, 3DES Keyed Digest KD* (paper to follow, there are 7 to chose from). Key exchange Diffie-Helleman, El Gammal, RSA Signature RSA, El Gammal, Rabin (Shamir variation), DSS Hash functions MD5, SHA I don't think that we are intending to tap Simons skill in designing ciphers. We have Ron Rivest and Taher El Gamal for that, plus help from Adi Shamir and if we get stuck I'll bang on some other doors. I really don't think we have a problem lacking cryptographers. Simon is putting in security input which is different. We have an equally star studded cast for that side of things (and if we get stuck I'll e-mail some more characters). Phill