Fast, pure and practical SHA-256 implementation.
A practical incremental and one-pass, pure API to the SHA-256 cryptographic hash algorithm according to FIPS 180-4 with performance close to the fastest implementations available in other languages.
The core SHA-256 algorithm is implemented in C and is thus expected to be as fast as the standard sha256sum(1) tool; for instance, on an Intel Core i7-3770 at 3.40GHz this implementation can compute a SHA-256 hash over 230 MiB of data in under one second. (If, instead, you require a pure Haskell implementation and performance is secondary, please refer to the SHA package.)
Additionally, this package provides support for
HMAC-SHA-256: SHA-256-based Hashed Message Authentication Codes (HMAC)
HKDF-SHA-256: HMAC-SHA-256-based Key Derivation Function (HKDF)
conforming to RFC6234, RFC4231, RFC5869, et al..
Relationship to the cryptohash package and its API
This package has been originally a fork of cryptohash-0.11.7 because the cryptohash package had been deprecated and so this package continues to satisfy the need for a lightweight package providing the SHA-256 hash algorithm without any dependencies on packages other than base and bytestring. The API exposed by cryptohash-sha256-0.11.*'s Crypto.Hash.SHA256 module is guaranteed to remain a compatible superset of the API provided by the cryptohash-0.11.7's module of the same name.
Consequently, this package is designed to be used as a drop-in replacement for cryptohash-0.11.7's Crypto.Hash.SHA256 module, though with a clearly smaller footprint by almost 3 orders of magnitude.