- This avoids having multiple `init()` functions for every combination
of optional parameters
- The API is consistent across all hash functions
- New options can be added later without breaking existing applications.
For example, this is going to come in handy if we implement parallelization
for BLAKE2 and BLAKE3.
- We don't have a mix of snake_case and camelCase functions any more, at
least in the public crypto API
Support for BLAKE2 salt and personalization (more commonly called context)
parameters have been implemented by the way to illustrate this.
Justification:
- reset() is unnecessary; states that have to be reused can be copied
- reset() is error-prone. Copying a previous state prevents forgetting
struct members.
- reset() forces implementation to store sensitive data (key, initial state)
in memory even when they are not needed.
- reset() is confusing as it has a different meaning elsewhere in Zig.
Instead of having all primitives and constructions share the same namespace,
they are now organized by category and function family.
Types within the same category are expected to share the exact same API.
This is a rewrite of the x25519 code, that generalizes support for
common primitives based on the same finite field.
- Low-level operations can now be performed over the curve25519 and
edwards25519 curves, as well as the ristretto255 group.
- Ed25519 signatures have been implemented.
- X25519 is now about twice as fast.
- mem.timingSafeEqual() has been added for constant-time comparison.
Domains have been clearly separated, making it easier to later add
platform-specific implementations.
This is a translation of the [official reference implementation][1] with
few other changes. The bad news is that the reference implementation is
designed for simplicity and not speed, so there's a lot of room for
performance improvement. The good news is that, according to the crypto
benchmark, the implementation is still fast relative to the other
hashing algorithms:
```
md5: 430 MiB/s
sha1: 386 MiB/s
sha256: 191 MiB/s
sha512: 275 MiB/s
sha3-256: 233 MiB/s
sha3-512: 137 MiB/s
blake2s: 464 MiB/s
blake2b: 526 MiB/s
blake3: 576 MiB/s
poly1305: 1479 MiB/s
hmac-md5: 653 MiB/s
hmac-sha1: 553 MiB/s
hmac-sha256: 222 MiB/s
x25519: 8685 exchanges/s
```
[1]: https://github.com/BLAKE3-team/BLAKE3
