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Re: Hello?


Robert Moskowitz says:
> Is the list totally quite or did the list operator drop my subscription in a
> bit bucket somewhere.

The list is not quiet so it is unlikely that you were subscribed.

> I have some questions on the IPSP drafts and would like to understand the
> difference between DES and DES-CBC, ie do they require different hardware
> engines?

Block ciphers can be used in various different modes to assure
security. When a block cipher is simply used to encode each block in
turn, it is being used in ECB, or Electronic Code Book, mode. This
mode is dangerous because the same plaintext will always encrypt as
the same cyphertext, thus giving information to the attacker about the
underlying plaintext. CBC is the Cipher Block Chaining mode -- in it,
the ciphertext of each block is XORed with the plaintext of the next
block before encryption. There are other modes -- Cipher Feedback
Mode, Output Feedback Mode, etc.

Any hardware that supports DES should probably handle DES in CBC mode.

Perry
References: