session key curiosity ???

[Werner Koch]

On Wed, 28 Sep 2005 16:42:06 -0700,   said:

> gpg --override-session-key 
> 2:1568A79A26ABCB75C294AA07AB73C53A7D168F2B898F93BE c:\r\s.txt

> when retyping, i accidentally changed the last character to an F 
> instead of an E

> and it *still* worked!

> should this be?

Yes.  With DES only the high 7 bits of a byte are used and the low
order bit is use as a parity bit.  We don't check that parity bit - it
is not required these days where everything is 8-bit clean.  This is
also the reason why we calculate with 56 or 168 bits when it comes to
DES.


Shalom-Salam,

   Werner