Re: [Hash2] Result extension

From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2024-12-09 22:16:05

On 12/9/24 21:49, Peter Dimov via Boost wrote:
> 
> Note that reaching a multiple of block_size is important,
> because it ensures that the secret key you passed as
> the seed is not left in the internal buffer of the hash
> algorithm, visible in memory dumps.
> 
> The test
> 
> https://github.com/pdimov/hash2/blob/develop/test/plaintext_leak.cpp
> 
> tries to catch these mistakes.
> 
> That's why this line
> 
> https://github.com/pdimov/hash2/blob/7a25f8518692b657e9272884519519fbaca2ec54/include/boost/hash2/md5.hpp#L257
> 
> is needed, for example.

Plain memset may be optimized away by the compiler. If you want to
guarantee this data doesn't leak, a secure memset should be used.