double encryption

Frank Tobin
Tue Jun 11 20:38:01 2002

On Tue, 11 Jun 2002, Volker Gaibler wrote:

> Yes, 3DES is DES 3 times (many implementations do
> encryption-decryption-encryption) but with 3 different keys. DES has a
> keylength of 56 bit, so for 3DES there is 168 bit keylength for the
> three parts. I don't know, how it's implemented in GnuPG.

The keylength might be that long, but the effective keylength of 3DES is
112 bits, not 168 bits.  For this reason, many implementation just use two
(alternating) DES keys.

Frank Tobin