hitower said:
Ordinary DES can be cracked in hours using specialized processors (they can be built for example on Xilinx
Really!? What a nice news!!! But what about the price? Because, if I would have infinite amount of money, I can theoretically break DES in 1 sec.
Read once more the post of
sgrudu. He was right - only goverment agencies can afford to break DES in 24 hours!
Well, to be precise let's make some calculations:
1. Let's get the DES IP core from Memec Design as a reference:
**broken link removed**
It takes 318 slices in X2V and provides encryption speed 86*4=344 Mbit/sec.
2. To break DES we will use simple brute-force approach. Frankly, there are some techniques based on linear and differential cryptoanalysis to optimize it a little bit, but all of them suppose that you have some billions pairs of plaintext-ciphertext and they require a lot of memory. Therefore, we will not consider them here. We will suppose that we have one block [64 bits] of plaintext and corresponding ciphertext. Our task: to find the key that was used for encryption by trying all 2^56 possible keys.
3. You have 1 million $. Do you really want to spend them for breaking DES and not for new Porsche and some nice girls? :wink: OK, you do!!!
4. I selected XC2V3000 for 600$ as the best part in the terms of size/price. It has 32256 slices. So, for 1M$ you could reach encryption speed [1M$/600]*[32256/318] about 170 000 * 344 Mbit/sec = 58480000 Mbit /sec.
5. So, to try one key you have to encrypt 64 bits of plaintext, therefore on your Xilinx-based supercomputer you will be able to try 913750 Mkeys/sec.
6. 2^56 = 72057594037927936. After division we will get:
72057594037927936/913750000000 = 78859 sec. It is about 21 hours. And again - it is only if you have 1 million dollars [I didn't count here the money for core and PCB design]!
As to me, I still stay on new Porsche and some nice girls!
Ace-X.