[Cryptography] SHA-256 decrypted (8 rounds)

[Michael Kjörling]

On 6 Nov 2023 15:18 +0000, from cryptography at metzdowd.com (McDair via cryptography):
> Hereby the code to decrypt 8 rounds of SHA-256 deterministically.
> An original input message length up to 447 bits (single block) is supported.

Neither SHA-256 nor SHA-512 are encryption algorithms. To "decrypt" a
hash value makes no sense.

Given that there are 2^447 possible inputs of 447 bits of length
(ignoring shorter inputs), but only 2^256 possible outputs of 256 bits
of length (for SHA-256), within a 2^447 input space, mathematically
there must statistically exist 2^(447-256) = 2^191 different possible
inputs for every single output. (It is of course possible that the
output distribution has non-uniform properties, especially after only
8 rounds, but likely still not on the order of 2^190.)

How does what you are showing compare against the current publicly
known attacks against SHA-256?

In English, what _exactly_ is your claim?

-- 
Michael Kjörling                     🔗 https://michael.kjorling.se
“Remember when, on the Internet, nobody cared that you were a dog?”