[NNTP] Re: Comments on draft-ietf-nntp-tls-nntp-05.txt

[Clive D.W. Feather]

Forrest J. Cavalier III said:
> It is my understanding that using symmetric ciphers on known and
> public plaintext (e.g. Usenet messages) allows easy recovery of
> the encryption keys.

This is a "known plaintext attack" or, for the POST command, a "chosen
plaintext attack".

These were a serious threat to WW2 cyphers (for example, they were at the
heart of breaking Enigma) but all modern cyphers, such as those used in
TLS, are designed to be immune to them.

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