Re: [hash2] Question about cryptographic guarantees of hash_append_unordered_range

From: Rainer Deyke (rdeyke_at_[hidden])
Date: 2024-12-10 11:18:08

On 10.12.24 08:29, Kostas Savvidis via Boost wrote:
> 
> 
>> On 8 Dec 2024, at 23:19, Peter Dimov via Boost <boost_at_[hidden]> wrote:
>> Vinnie Falco wrote:
>>> On Sun, Dec 8, 2024 at 11:27 AM Ivan Matek via Boost
>>> <boost_at_[hidden]>
>>> wrote:
>>>> ...sum is commutative.
>>> Bitwise XOR and modular unsigned multiplication are also commutative.
>>
>> Bitwise xor has the problem that xoring two equal values yields 0, so
>> the sequences [1], [1, 1, 1], [1, 2, 2] and so on all hash to the same thing.
> 
> And addition gives the same result for [3] , [2,1], [1,1,1] etc.

No, because the elements themselves are not added together.  Only their 
hashes are.

-- 
Rainer Deyke - rainerd_at_[hidden]