At 07:32 PM 1/23/96 -0500, David A Wagner wrote:
If you want authentication, you must use a crypto-strength MAC. Encryption (be it RC4, DES, etc.) is not enough.
Not so: If the message is encrypted and checksummed with a simple not non cryptographic checksum, this gives you everything a MAC gives you, plus the message is secret. MACs are only useful in the strange and unsual case where you want authentification using a symmetric key, but you want to transmit in the clear. I cannot see any reason why anyone would ever wish to use a MAC except perhaps to obey government bans on encrypted messages. --------------------------------------------------------------------- | We have the right to defend ourselves | http://www.jim.com/jamesd/ and our property, because of the kind | of animals that we are. True law | James A. Donald derives from this right, not from the | arbitrary power of the state. | jamesd@echeque.com