sha512

A pure Haskell implementation of SHA-512 and HMAC-SHA512 on strict and lazy ByteStrings, as specified by RFC's 6234 and 2104.

Usage

A sample GHCi session:

  > :set -XOverloadedStrings
  >
  > -- import qualified
  > import qualified Crypto.Hash.SHA512 as SHA512
  >
  > -- 'hash' and 'hmac' operate on strict bytestrings
  >
  > let hash_s = SHA512.hash "strict bytestring input"
  > let hmac_s = SHA512.hmac "strict secret" "strict bytestring input"
  >
  > -- 'hash_lazy' and 'hmac_lazy' operate on lazy bytestrings
  > -- but note that the key for HMAC is always strict
  >
  > let hash_l = SHA512.hash_lazy "lazy bytestring input"
  > let hmac_l = SHA512.hmac_lazy "strict secret" "lazy bytestring input"
  >
  > -- results are always unformatted 512-bit (64-byte) strict bytestrings
  >
  > import qualified Data.ByteString as BS
  >
  > BS.take 10 hash_s
  "\189D*\v\166\245N\216\&1\243"
  > BS.take 10 hmac_l
  "#}9\185\179\233[&\246\205"
  >
  > -- you can use third-party libraries for rendering if needed
  > -- e.g., using base64-bytestring:
  >
  > import qualified Data.ByteString.Base64 as B64
  >
  > B64.encode (BS.take 16 hash_s)
  "vUQqC6b1Ttgx8+ydx4MmtQ=="
  > B64.encode (BS.take 16 hmac_l)
  "I305ubPpWyb2zUi4pwDkrw=="

Documentation

Haddocks (API documentation, etc.) are hosted at docs.ppad.tech/sha512.

Performance

The aim is best-in-class performance for pure, highly-auditable Haskell code.

Current benchmark figures on an M4 Silicon MacBook Air look like (use cabal bench to run the benchmark suite):

  benchmarking ppad-sha512/SHA512 (32B input)/hash
  time                 237.8 ns   (237.4 ns .. 238.2 ns)
                       1.000 R²   (1.000 R² .. 1.000 R²)
  mean                 237.3 ns   (237.1 ns .. 237.8 ns)
  std dev              1.226 ns   (854.2 ps .. 1.982 ns)

  benchmarking ppad-sha512/HMAC-SHA512 (32B input)/hmac
  time                 1.017 μs   (1.013 μs .. 1.021 μs)
                       1.000 R²   (1.000 R² .. 1.000 R²)
  mean                 1.015 μs   (1.014 μs .. 1.018 μs)
  std dev              7.727 ns   (6.045 ns .. 9.684 ns)

You should compile with the 'llvm' flag for maximum performance.

Security

This library aims at the maximum security achievable in a garbage-collected language under an optimizing compiler such as GHC, in which strict constant-timeness can be challenging to achieve.

The HMAC-SHA512 functions within pass all Wycheproof vectors, as well as various other useful unit test vectors found around the internet.

If you discover any vulnerabilities, please disclose them via security@ppad.tech.

Development

You'll require Nix with flake support enabled. Enter a development shell with:

$ nix develop

Then do e.g.:

$ cabal repl ppad-sha512

to get a REPL for the main library.

Attribution

This implementation has benefitted immensely from the SHA package available on Hackage, which was used as a reference during development. Many parts wound up being direct translations.