Re: Why is blowfish so slow? Other fast algorithms?

["James A. Donald" <jamesd@echeque.com>]

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.

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