[bash]

Originally Posted by Desert Mariner

Some examples of the use of brute force, from RSA Labs Encryption Challenges, using distributed networks, not a stand-alone machine.

• 56-bit cracked in 250 days by 16,738 total participants
• 64-bit cracked in 1757 days (4.8 years) by 327,856 participants
• 72-bit remains uncracked after 7,241 days (19.8 years) and 143,497 participants (projected time remaining 27,828 days (76+ years))

To me, the question isn’t, Can you crack the encryption?, but Is it worth doing so? In the case of the above 72-bit key, even if you manage to crack it, does a single decrypt (or even a whole day’s worth of decrypts) provide any usable intelligence decades after the fact?

Note that the SAVILLE system uses a 120-bit key. It would take trillions of years to brute force a single key if you could build a system that tried a quadrillion keys per second. So the time taken to recover a single key with a brute force search (even with mathematical principals like the Birthday Paradox) is directly related to a functionality of decryption. If a single key takes a trillion years to recover the practicality of the system is effectively zero.