rigel-0.0.4 has been yanked.
rigel

About
rigel is a minimal implementation of HMAC with SHA512, which is optimized for use
with embedded devices. rigel minimizes the amount of allocations made, while
still upholding performance speed.
You can read more about these optimizations here.
Security
This library has at no point received any formal cryptographic/security audit. It should be used at own risk.
Example
With the one-shot API:
extern crate rigel;
let mac = hmac_sha512;
assert!;
With streaming messages:
extern crate rigel;
let mut mac = init;
mac.update;
let res = mac.finalize;
assert!;
Performance
test RustCrypto ... bench: 2,727 ns/iter
test orion ... bench: 2,461 ns/iter
test rigel_one_shot ... bench: 2,093 ns/iter
test rigel_stream ... bench: 2,161 ns/iter
test ring ... bench: 3,357 ns/iter
This was benchmarked on a MacBook Air 1,6 GHz Intel Core i5, 4GB.
License
rigel is licensed under the MIT license. See the LICENSE file for more information.