Hi: While working on rhashtable it came to me that this whole concept of arch_fast_hash is flawed. CRCs are linear functions so it's fairly easy for an attacker to identify collisions or at least eliminate a large amount of search space (e.g., controlling the last bit of the hash result is almost trivial, even when you add a random seed).
So what exactly are we going to use arch_fast_hash for? Presumably it's places where security is never goint to be an issue, right? Even if security wasn't an issue, straight CRC32 has really poor lower-order bit distribution, which makes it a terrible choice for a hash table that simply uses the lower-order bits. Cheers, -- Email: Herbert Xu <herb...@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
