double encryption

Volker Gaibler
Tue Jun 11 20:23:01 2002


On Tue, Jun 11, 2002 at 08:00:15AM -0600, Peter T. Abplanalp wrote:
> hmmmm.  isn't 3DES just DES 3 times?  given the above, how much
> stronger is 3DES than 2DES and DES?

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. 

But triple encryption is thought of increasing the effective key length
significantly - even there is no proof yet. So 2DES is not really worth
more than DES, but 3DES is still very secure. It has an effective key
size of about 110 bit - and about 80 bit is supposed to be the maximum
for intelligence agencies to be crackable. 


 Volker Gaibler                                 contact:         
 OpenPGP key: 0x86ECAC0B
 get my public key from website above