Corrupted MAC on input

[Darren Tucker]

Deron Meranda wrote:

> At one point I started performing my own tests with lower and lower
> levels of debuging, almost to the point of capturing all the raw
> packet buffers just prior to encryption.  I even inserted extra debug
> code so I could check every single step of the MAC computation and
> verification.  I just could not explain what I saw, but it looked like
> a single byte was always getting changed.  It was not a random pattern
> at all.  If I recall correctly, I had ruled out the MAC computation
> itself.  Also strangely the encrypted packets were identical.  But
> somehow after decryption the plaintext buffers were different.  I hope
> I'm recalling this correctly, but I think I am.

If the encrypted packets are identical but decrypt differently that 
sounds like a problem in the crypto itself.  Which algorithm were you 
using?  Are you using the HP ANSI C compiler to compile OpenSSL?

-- 
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
     Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.