Dynamic SHA256 Verification Noir

Dynamic arrays (slices) are expensive to use when computing SHA256 hashes within Noir.
By using recursive proofs and field encoding, we can design a circuit where the verification cost of a preimage for a given SHA256 hash remains constant, regardless of the preimage's length, up to a specified maximum. For example, with a fixed byte length of ~32k it costs ~430k gates to verify, with the num of gates and thus proving time increasing for larger byte lengths.

Circuit Generation and Demo

1. Generate sub-circuit verification keys and hashes
   python scripts/generate_circuits.py <chunk_num>

2. Create hash list
   python scripts/create_hash_list.py > ./example/src/hash_list.nr

3. Create recursive proofs and test verification
   python scripts/full_demo.py