On 13 Jan 2010, at 14:40, Philip Newton wrote: [...] > Well, that said, is the "very low chance" not on the order of the > chance that you'll be run over by a bus in the morning, or that one of > the files will be changed through cosmic rays or bit rot in the > magnetic domains of the hard disk platter?
In the case of SHA-256, the odds are low enough that the universe is likely to end before you find a collision.