![]() | |||||||||||||
Messages in this thread |
David Lang wrote: >On Mon, 18 Aug 2003, Andreas Dilger wrote: >> It wasn't even vanishingly small... We had a problem in our code where >> two readers got the same 64-bit value calling get_random_bytes(), and >> we were depending on this 64-bit value being unique. This problem was >> fixed by putting a spinlock around the call to get_random_bytes(). > >if the number is truely random then there should be a (small but finite) >chance that any two reads will return the same data. counting on a random >number to be unique is not a good idea. Have you ever worked out how small a number 2^-64 is? You might be surprised. For most practical purposes, 2^-64 is effectively zero. If you see a 64-bit values repeat twice in a row when querying a cryptographic pseudorandom generator, the crypto-PRNG is almost surely broken. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
| Last update: 2005-03-22 12:47 [from the cache] ©2003-2008 | |||||||||||||