Re: [hash2] Question about cryptographic guarantees of hash_append_unordered_range

From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2024-12-08 20:15:25

El 08/12/2024 a las 21:04, Ion Gaztañaga via Boost escribió:
> El 08/12/2024 a las 20:49, Vinnie Falco via Boost escribió:
>> On Sun, Dec 8, 2024 at 11:44 AM Peter Dimov via Boost 
>> <boost_at_[hidden]>
>> wrote:
>>
>>> Matt Borland is considering proposing boost::uint128_t to Core, but that
>>> would mean depending on Core.
>>>
>>
>> Would it be better to make this its own library? More fine-grained
>> libraries could have appeal to Boost users.
> 
> I wouldn't like to add another dependency to the library users.
> 
> Wouldn't be acceptable to take all the bits from the hash, treat the 
> hash as an array 64 bit or 32 bits hashes and apply something like 
> hash_combine or similar to each element so that we combine big hashes 
> preserving all bits from result_type?
> 
> This would also scale to 512 bit or bigger hashes.

Auto-replying...

Just realized that the operation must be commutative so hash_combine 
would not work. Maybe just adding those individual hashes could do the 
trick.

Best,

Ion