Re: Plaintext

Evan Jeffrey (
Wed, 02 Jul 1997 22:17:15 -0500

>If, as in the real world, you can't necessarily tell when you've found
>the decryption of any layer but the last layer, breaking a triple 56-bit
>RC5 by brute force will take you (2^56)^2, rather than 3, times as long
>as breaking a single 56-bit RC5 also by brute force. :-)

except that many triple DES implementations use the same key for the first
and third encryption. So it is really "double DES + some an extra
encryption to make it look noisy"

As for triple RC5, I don't know why one would do that, since the RC5
algorithm is parameterized to allow key sizes of up to 128 bits already.

Evan Jeffrey

The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore all progress
depends on the unreasonable man.