fix bit size in puzzle

[qy3u]

The bit size of bls12-377 Fr is 253, not 254.

[d0cd]

The additional padding bit does not affect the correctness of the puzzle.
This change, while valid, would break compatibility with the existing puzzle.
As a result, I would not recommend this change.

[d0cd]

Closing this issue for now, but please feel free to reopen if you have any strong concerns.

[qy3u]

Hi @d0cd. I believe this change wouldn't be a breaking change.

Leave bits were converted to bytes before hashing. Therefore, hash_leave(&vec![false; 253]) and hash_leave(&vec![false; 254]) will produce the same result because vec![false; 254] and vec![false; 255] (with a prepended bit) are converted into the same bytes.

snarkVM/console/algorithms/src/keccak/hash.rs

Line 31 in d170a9f

(1, 256) => bits_from_bytes_le(&sha3_256_native(&bytes_from_bits_le(input))).collect(),

If this change is valid and doesn't introduce any breaking changes, I think we should merge it during the Testnet phase. Let's avoid having these slightly odd [bool; 253], [bool; 253], ... , [bool; 254], ...] leaves in the mainnet.

[d0cd]

Ah good catch @qy3u!
If its just a cosmetic change, then is there a strong reason for changing the code?
It would also be great if we could add tests verifying that solutions aren't changed

[vicsn]

In case no change to the padding is made, I would still consider adding a comment in the code for future readers.