ed448goldilocks/HISTORY.txt

May 3, 2104:
    Minor changes to internal routines mean that this version is not
    compatible with the previous one.

    Added ARM NEON code.
    
    Added the ability to precompute multiples of a partner's public key.  This
    takes slightly longer than a signature verification, but reduces future
    verifications with the precomputed key by ~63% and ECDH by ~70%.
    
        goldilocks_precompute_public_key
        goldilocks_destroy_precomputed_public_key
        goldilocks_verify_precomputed
        goldilocks_shared_secret_precomputed
    
    The precomputation feature are is protected by a macro
        GOLDI_IMPLEMENT_PRECOMPUTED_KEYS
    which can be #defined to 0 to compile these functions out.  Unlike most
    of Goldilocks' functions, goldilocks_precompute_public_key uses malloc()
    (and goldilocks_destroy_precomputed_public_key uses free()).
    
    Changed private keys to be derived from just the symmetric part.  This
    means that you can compress them to 32 bytes for cold storage, or derive
    keypairs from crypto secrets from other systems.
        goldilocks_derive_private_key
        goldilocks_underive_private_key
        goldilocks_private_to_public
    
    Fixed a number of bugs related to vector alignment on Sandy Bridge, which
    has AVX but uses SSE2 alignment (because it doesn't have AVX2).  Maybe I
    should just switch it to use AVX2 alignment?
    
    Beginning to factor out curve-specific magic, so as to build other curves
    with the Goldilocks framework.  That would enable fair tests against eg
    E-521, Ed25519 etc.  Still would be a lot of work.
    
    More thorough testing of arithmetic.  Now uses GMP for testing framework,
    but not in the actual library.
    
    Added some high-level tests for the whole library, including some (bs)
    negative testing.  Obviously, effective negative testing is a very difficult
    proposition in a crypto library.

March 29, 2014:
    Added a test directory with various tests.  Currently testing SHA512 Monte
    Carlo, compatibility of the different scalarmul functions, and some
    identities on EC point ops.  Began moving these tests out of benchmarker.
    
    Added scan-build support.
    
    Improved some internal interfaces.  Made a structure for Barrett primes
    instead of passing parameters individually.  Moved some field operations
    to places that make more sense, eg Barrett serialize and deserialize.  The
    deserialize operation now checks that its argument is in [0,q).
    
    Added more documentation.
    
    Changed the names of a bunch of functions.  Still not entirely consistent,
    but getting more so.
    
    Some minor speed improvements.  For example, multiply is now a couple cycles
    faster.
    
    Added a hackish attempt at thread-safety and initialization sanity checking
    in the Goldilocks top-level routines.
    
    Fixed some vector alignment bugs.  Compiling with -O0 should now work.
    
    Slightly simplified recode_wnaf.

    Add a config.h file for future configuration.  EXPERIMENT flags moved here.
    
    I've decided against major changes to SHA512 for the moment.  They add speed
    but also significantly bloat the code, which is going to hurt L1 cache
    performance.  Perhaps we should link to OpenSSL if a faster SHA512 is desired.
    
    Reorganize the source tree into src, test; factor arch stuff into src/arch_*.
    
    Make most of the code 32-bit clean.  There's now a 32-bit generic and 32-bit
    vectorless ARM version.  No NEON version yet because I don't have a test
    machine (could use my phone in a pinch I guess?).  The 32-bit version still
    isn't heavily optimized, but on ARM it's using a nicely reworked signed/phi-adic
    multiplier.  The squaring is also based on this, but could really stand some
    improvement.
    
    When passed an even exponent (or extra doubles), the Montgomery ladder should
    now be accept points if and only if they lie on the curve.  This needs
    additional testing, but it passes the zero bit exponent test.
    
    On 32-bit, use 8x4x14 instead of 5x5x18 table organization.  Probably there's
    a better heuristic.

March 5, 2014:
    First revision.
    
    Private keys are now longer.  They now store a copy of the public key, and
    a secret symmetric key for signing purposes.
    
    Signatures are now supported, though like everything else in this library,
    their format is not stable.  They use a deterministic Schnorr mode,
    similar to EdDSA.  Precomputed low-latency signing is not supported (yet?).
    The hash function is SHA-512.
    
    The deterministic hashing mode needs to be changed to HMAC (TODO!).  It's
    currently envelope-MAC.
    
    Probably in the future there will be a distinction between ECDH key and
    signing keys (and possibly also MQV keys etc).
    
    Began renaming internal functions.  Removing p448_ prefixes from EC point
    operations.  Trying to put the verb first.  For example,
    "p448_isogeny_un_to_tw" is now called "twist_and_double".
    
    Began documenting with Doxygen.  Use "make doc" to make a very incomplete
    documentation directory.
    
    There have been many other internal changes.

Feb 21, 2014:
    Initial import and benchmarking scripts.
    
    Keygen and ECDH are implemented, but there's no hash function.