On Tue, 27 Sep 2005 09:14:31 -0400, Steven M. Bellovin wrote:

Hello,

> Lack of integrity-checking in a crypto protocol is indeed serious.  For 
> telnet, it's' slightly worse for CFB than for CBC, but both are 
> seriously flawed against replay attacks.

Is this flaw a problem in practice? If the connection data are encrypted
with a secret key, how can an attacker replace them with different data
without producing just uncontrollable garbage? If he can replay
previously transmitted data, what can he achieve, since he don't know what
actually he's replaying?

Pavel Cahyna