Fix HMAC usage - Githubissues

dd86k / blake2-d

Pure D implementation of BLAKE2 + DUB package

https://code.dlang.org/packages/blake2-d

Boost Software License 1.0

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Fix HMAC usage #3

Open dd86k opened 2 years ago

dd86k commented 2 years ago

While the Digest API uses std.digest.hmac.HMAC for HMAC, which adds a secret hashed key using the template API, the way BLAKE2 does is just... Weird.

At initiation:

Parameter block index 0 byte 1 (little-endian) sets key size in bytes.
Key is XOR'd with state alongside IV (ulong for b, uint for s, see the inner_t alias).

Which is simply not possible with the HMAC structure template. Unless there's a hack I don't know of.

dd86k commented 2 years ago

I think I could do a void key(scope const(ubyte)[] data...) function that performs a "second stage" initiation.

dd86k commented 2 years ago

Got key stuff in but that's not hmac so keeping this open.

dd86k commented 2 years ago

For the HMAC templates to work, the key needs to be initiated at compile-time. The issue is, while the default key is the IV, they are of different types in the s (uint) and b (ulong) variants.