Hi JP & George, My function names: - SipHash -> siphash - HalfSipHash -> hsiphash It appears that hsiphash can produce either 32-bit output or 64-bit output, with the output length parameter as part of the hash algorithm in there. When I code this for my kernel patchset, I very likely will only implement one output length size. Right now I'm leaning toward 32-bit. Questions: - Is this a reasonable choice? - When hsiphash is desired due to its faster speed, are there any circumstances in which producing a 64-bit output would actually be useful? Namely, are there any hashtables that could benefit from a 64-bit functions? - Are there reasons why hsiphash with 64-bit output would be reasonable? Or will we be fine sticking with 32-bit output only? With both hsiphash and siphash, the division of usage will probably become: - Use 64-bit output 128-bit key siphash for keyed RNG-like things, such as syncookies and sequence numbers - Use 64-bit output 128-bit key siphash for hashtables that must absolutely be secure to an extremely high bandwidth attacker, such as userspace directly DoSing a kernel hashtable - Use 32-bit output 64-bit key hsiphash for quick hashtable functions that still must be secure but do not require as large of a security margin Sound good? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
