[New Hints] cairo_keccak.json

[pefontana]

Implement the remaining hints in 0.8.2.json

NewHint#66 SIMILAR to CAIRO_KECCAK_FINALIZE

assigned: pelito
status: in review

                "# Add dummy pairs of input and output.",
                "_keccak_state_size_felts = int(ids.KECCAK_STATE_SIZE_FELTS)",
                "_block_size = int(ids.BLOCK_SIZE)",
                "assert 0 <= _keccak_state_size_felts < 100",
                "assert 0 <= _block_size < 1000",
                "inp = [0] * _keccak_state_size_felts",
                "padding = (inp + keccak_func(inp)) * _block_size",
                "segments.write_arg(ids.keccak_ptr_end, padding)"

NewHint#67 SIMILAR to BLOCK_PERMUTATION_WHITELIST

assigned: pelito
status: in review

                "_keccak_state_size_felts = int(ids.KECCAK_STATE_SIZE_FELTS)",
                "assert 0 <= _keccak_state_size_felts < 100",
                "output_values = keccak_func(memory.get_range(",
                "    ids.keccak_ptr_start, _keccak_state_size_felts))",
                "segments.write_arg(ids.output, output_values)"

NewHint#68 SIMILAR to SHA256_INPUT

assigned: pelito
status: wip

                "ids.full_word = int(ids.n_bytes >= 8)"