Biggest Public-key Crypto Crack Ever

galore writes "Certicom's ECC2k-108 Elliptic Curve Discrete Logarithm challenge has been broken! This was the largest public calculation ever to use a complex parallel algorithm. $5,000 dollars in winnings will be donated to the Free Software Foundation. Congratulations to everyone who participated, including team Slashdot! " There seems to be conflicting versions of info about the prize money - some says 8,000 to the Apache Foundation, others say 5,000 to the FSF.

Comments

DES has no such loophole

[rjh]

First, I am a professional information security consultant. Second, no, this is not professional advice; do not rely on it without first verifying.

However, unlike DES, there is no known mathematical loophole

Wrong answer, thank you for playing. DES is one of the most, if not the, most thoroughly-analyzed ciphers of all time. So far, the best way to break DES is by a brute force attack. There are some attacks against it which some people use as proof that the NSA put a backdoor in it, but these attacks are extremely esoteric -- for instance, the key complementation property means you only have to test half the possible keys; this reduces the difficulty of some attacks (chosen-plaintext attacks, specifically, although I think Eli Biham has a known-plaintext version) by a factor of 2--meaning the keyspace is only of size 2**55, not 2**56.

The rules for using DES are simple. Don't use weak keys; don't use complementary keys; use it in DESede (aka TripleDES) mode. The resulting ciphersystem is as close to unbreakable as you're likely to ever get. If your system is eventually broken, you can be reasonably certain that the cipher was not the subsystem which suffered the breach.

I trust DESede more than I trust Blowfish, more than I trust IDEA, more than any other symmetric ciphersystem out there.

Interestingly enough, so does Schneier. A few months back at a crypto conference someone in the gallery asked him what the strongest cipher today was. As I recall, his words were "Triple DES. There is no question."

Not cryptographically weak....

[Noer]

Don't misunderstand what this means. The ECC algorithm was not cracked; an encrypted message was cracked after a ridiculously large amount of computing power was applied to it. Perhaps this means larger key sizes are needed, or smaller windows of using the same key. However, unlike DES, there is no known mathematical loophole; the algorithm has not been shown to be insecure. If there is a loophole, then increasing key size doesn't help; the algorithm is flawed. But in this case, all that's needed is larger key sizes. Arbitrarily large keys allow for encryption that can't be cracked with all the computing horsepower on the planet within the age of the universe.

I'd be more interested in real cryptographic algorithm analysis of the algorithm, but that is not by any means my forte.