sha256

Pure Haskell SHA-256, HMAC-SHA256 (docs.ppad.tech/sha256).
git clone git://git.ppad.tech/sha256.git
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CHANGELOG (2591B)

      1 # Changelog
      2 
      3 - 0.3.4 (2026-07-06)
      4   * Reverts the unrolled MAC comparison introduced in 0.3.3, which was
      5     found to introduce timing variation on both aarch64 and x86-64 when
      6     compiled via the LLVM backend (the NCG backend was unaffected).
      7 
      8 - 0.3.3 (2026-07-06)
      9   * The constant-time 'Eq' on 'MAC' now folds over the two buffers
     10     directly, rather than materialising an intermediate ByteString
     11     holding their XOR on the heap. Semantics are unchanged.
     12 
     13   * Improves the performance of constant-time MAC comparison.
     14 
     15 - 0.3.2 (2026-02-01)
     16   * The library has been refactored substantially to achieve greater
     17     control over heap allocation, particularly around HMAC calculation.
     18 
     19   * A couple of very low-level functions, '_hmac_rr' and '_hmac_rsb' are
     20     now quietly exported for calculating specialized destructive HMAC
     21     operations, mostly of use to HMAC-DRBG implementations.
     22 
     23   * HMAC performance is also improved, now only about 2x that of hash
     24     computation.
     25 
     26 - 0.3.1 (2026-01-11)
     27   * Adds a basic quickcheck test suite for asserting memory safety of
     28     library functions on random inputs.
     29 
     30 - 0.3.0 (2026-01-10)
     31   * The HMAC functions now produce a value of type MAC, which is a
     32     newtype over a ByteString. The 'Eq' instance for MAC compares values
     33     in constant time.
     34 
     35 - 0.2.5 (2026-01-08)
     36   * We now check if the ARM cryptographic extensions are available, and,
     37     if so, use them to calculate hashes. If they're unavailable we
     38     simply use the pure implementation as a fallback. This yields about
     39     a 5x performance boost for 'hash' and 3.5x boost for 'hmac' (again,
     40     when available).
     41 
     42   * Allocation for both the 'hash' and 'hmac' functions has been reduced
     43     dramatically, mostly by optimising the padding internals, and is now
     44     constant with respect to input.
     45 
     46 - 0.2.4 (2025-12-28)
     47   * Adds an 'llvm' build flag and tests with GHC 9.10.3.
     48 
     49 - 0.2.3 (2025-01-21)
     50   * Improves padding handling for the strict bytestring case, yielding
     51     performance increases for both 'hash' and 'hmac'.
     52 
     53 - 0.2.2 (2025-01-07)
     54   * Minor bytestring-handling optimisations.
     55 
     56 - 0.2.1 (2024-10-13)
     57   * Adds an INLINE pragma to an internal step function.
     58 
     59   * 'hmac' no longer calls 'hmac_lazy', which has no practical effect
     60     other than to clean up profiling reports generated by GHC.
     61 
     62 - 0.2.0 (2024-10-07)
     63   * 'hmac' and 'hmac_lazy' now hash long keys before computing a HMAC,
     64     instead of throwing an error, matching RFC 2104's suggested behaviour.
     65 
     66 - 0.1.0 (2024-09-14)
     67   * Initial release, supporting SHA256 and HMAC-SHA256 on strict and lazy
     68     bytestrings.