On 2019-08-23 13:08, Adam Borowski wrote:
the improved collision resistance of xxhash64 is not a reason as if you intend to dedupe you want a crypto hash so you don't need to verify.
The improved collision resistance is a roughly 10 orders of magnitude reduction in the chance of a collision. That may not matter for most, but it's a significant improvement for anybody operating at large enough scale that media errors are commonplace.
Also, you would still need to verify even if you're using whatever the fanciest new collision resistant cryptographic hash is, because the number of possible input values is still more than _nine thousand_ orders of magnitude larger than the total number of output values even if we use a 512-bit cryptographic hash.
