Quote from: dice64 on August 11, 2013, 01:40:13 PM

Hilariously this is how the encryption on the ps3 was broken.

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In December 2010, a group calling itself fail0verflow announced recovery of the ECDSA private key used by Sony to sign software for the PlayStation 3 game console. However, this attack only worked because Sony did not properly implement the algorithm, because k was static instead of random. As pointed out in the signal generation algorithm, this makes d_A solvable and the entire algorithm useless.[4]

http://en.wikipedia.org/wiki/Elliptic_Curve_DSA#Security

They always used a k value of 4, instead of it being random.

The problem with bitcoin is that since we have a public database storing every transaction, it not only needs to be random, it needs to be unique per address.

How likely is a collision here in general, if we're not dealing with a broken RNG (like it seems to be the case with the android wallets)?
What is the value range for k?