Fast, pure and practical SHA-256 implementation

Latest on Hackage:[email protected]:4

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BSD-3-Clause licensed

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A practical incremental and one-pass, pure API to the SHA-256 hash algorithm (including HMAC support) with performance close to the fastest implementations available in other languages.

The implementation is made in C with a haskell FFI wrapper that hides the C implementation.

NOTE: This package has been forked off cryptohash-0.11.7 because the cryptohash package has been deprecated and so this package continues to satisfy the need for a lightweight package providing the SHA256 hash algorithm without any dependencies on packages other than base and bytestring.

Consequently, this package can be used as a drop-in replacement for cryptohash's Crypto.Hash.SHA256 module, though with a clearly smaller footprint.


  • Use __builtin_bswap{32,64} only with GCC >= 4.3 (#1)

  • new hmac and hmaclazy functions providing HMAC-SHA1 computation conforming to RFC2104 and RFC4231
  • fix unaligned memory-accesses

  • switch to ‘safe’ FFI for calls where overhead becomes neglible
  • removed inline assembly in favour of portable C constructs
  • fix 32bit length overflow bug in hash function
  • fix inaccurate context-size
  • add context-size verification to incremental API operations

  • first version forked off cryptohash-0.11.7 release
Depends on 2 packages(full list with versions):