ElGamal: key length vs performance

[Werner Koch]

On Sun, 02 Apr 2006 14:00:07 +0200, Qed  said:

> Different implementations => different speeds.
> You cannot rely on a particular piece software to infer general
> performance figures for crypto algos.


Here are some figures from libgcrypt which uses the same
implementation as gnupg does.  CFB mode is used by OpenPGP.  The
numbers are for 10^6 bytes encryption/decryption including key setup
for each.  CPU is a Pentium M at 1500MHz.


           ECB             CBC             CFB             
           --------------- --------------- --------------- 
3DES         120ms   120ms   130ms   130ms   130ms   120ms 
CAST5         40ms    30ms    50ms    60ms    40ms    50ms 
BLOWFISH      50ms    50ms    60ms    70ms    60ms    60ms 
AES           30ms    30ms    40ms    40ms    30ms    40ms 
AES192        30ms    30ms    40ms    50ms    40ms    40ms 
AES256        30ms    40ms    50ms    40ms    50ms    40ms 
TWOFISH       40ms    30ms    50ms    40ms    40ms    50ms 
DES           50ms    60ms    70ms    70ms    60ms    70ms 
TWOFISH128    40ms    30ms    50ms    40ms    40ms    40ms 
SERPENT128    90ms    90ms   100ms   100ms   100ms   100ms 
SERPENT192    90ms    90ms   100ms   100ms   100ms    90ms 
SERPENT256    90ms    90ms   100ms   100ms   100ms   100ms 
RFC2268_40   120ms    70ms   130ms    90ms   130ms   120ms 


Shalom-Salam,

   Werner