## std::crypto::hashes::keccak256
| Procedure | Description |
| ----------- | ------------- |
| to_bit_interleaved | given two 32 -bit unsigned integers ( standard form ), representing upper and lower<br /> portion of a 64 -bit unsigned integer ( actually a keccak-[1600, 24] lane ),<br /> this function converts them into bit interleaved representation, where two 32 -bit<br /> unsigned integers ( even portion & then odd portion ) hold bits in even and odd<br /> indices of 64 -bit unsigned integer ( remember it's represented in terms of<br /> two 32 -bit elements )<br /><br /> Read more about bit interleaved representation in section 2.1 of https://keccak.team/files/Keccak-implementation-3.2.pdf<br /><br /> See https://github.com/itzmeanjan/merklize-sha/blob/1d35aae9da7fed20127489f362b4bc93242a516c/include/utils.hpp#L123-L149 |
| from_bit_interleaved | given two 32 -bit unsigned integers ( bit interleaved form ), representing even and odd<br /> positioned bits of a 64 -bit unsigned integer ( actually a keccak-[1600, 24] lane ),<br /> this function converts them into standard representation, where two 32 -bit<br /> unsigned integers hold higher ( 32 -bit ) and lower ( 32 -bit ) bits of standard<br /> representation of 64 -bit unsigned integer ( remember it's represented in terms of<br /> two 32 -bit elements )<br /><br /> This function reverts the action done by `to_bit_interleaved` function implemented above.<br /><br /> Read more about bit interleaved representation in section 2.1 of https://keccak.team/files/Keccak-implementation-3.2.pdf<br /><br /> See https://github.com/itzmeanjan/merklize-sha/blob/1d35aae9da7fed20127489f362b4bc93242a516c/include/utils.hpp#L151-L175 |
| hash.13 | given 64 -bytes input, in terms of sixteen 32 -bit unsigned integers, where each pair<br /> of them holding higher & lower 32 -bits of 64 -bit unsigned integer ( reinterpreted on<br /> host CPU from little endian byte array ) respectively, this function computes 32 -bytes<br /> keccak256 digest, held on stack top, represented in terms of eight 32 -bit unsigned integers,<br /> where each pair of them keeps higher and lower 32 -bits of 64 -bit unsigned integer respectively<br /><br /> See https://github.com/itzmeanjan/merklize-sha/blob/1d35aae9da7fed20127489f362b4bc93242a516c/include/keccak_256.hpp#L232-L257 |