On Wed, 16 Oct 2024 16:48:12 +0100 "Medvedkin, Vladimir" <vladimir.medved...@intel.com> wrote:
> Hi Stephen, > > Thanks for introducing this hash function. > > I have just a few nits: > > On 01/08/2024 16:31, Stephen Hemminger wrote: > > The existing hash functions in DPDK are not cryptographically > > secure and can be subject to carefully crafted packets causing > > DoS attack. > Currently in DPDK we have 3 hash functions, 2 of them can be used with > our cuckoo hash table implementation: > > 1. CRC - Very weak, do not use with hash table if you don't fully > control all keys to install into a hash table. > > 2. Toeplitz - keyed hash function, not used with hash tables, fastest if > you have GFNI, level of diffusion fully depends on the hash key, weak > against differential crypto analysis. Technically may be used with hash > tables in number of usecases. > > 3. Jenkins hash (lookup3) - and here I can not say that it is not secure > and it is subject to collisions. I'm not aware on any successful attacks > on it, it has a great diffusion (see https://doi.org/10.1002/spe.2179). > It is also keyed with the same size of the key as rte_hsiphash(). > > So I won't agree with this sentence. I am not a crypto or hash expert. This text is based on the statements by the original author of siphash who does have such expertise. See the wikipedia page: https://en.wikipedia.org/wiki/SipHash and the original paper: https://web.archive.org/web/20170327151630/https://131002.net/siphash/siphash.pdf The problem is that Jenkins and Toeplitz "were designed to have a close-to-uniform distribution, not to meet any particular cryptographic goals"
