I finally got CUDA working ok and I did a benchmark which shows that CUDA is slower than my CPU! I don't understand. Am I doing something wrong? My graphics card is an Nvidia GeForce 8600M GS. Here are my results:

root@bt:~# pyrit benchmark
Pyrit 0.3.0 (C) 2008-2010 Lukas Lueg
This code is distributed under the GNU General Public License v3+

Running benchmark (1363.2 PMKs/s)... /

Computed 1403.20 PMKs/s total.
#1: 'CUDA-Device #1 'GeForce 8600M GS'': 630.5 PMKs/s (RTT 3.1)
#2: 'CPU-Core (SSE2)': 678.5 PMKs/s (RTT 2.8)