Crate libvctrl_sha512 

Zero-dependency cryptographic primitives: SHA-512, HMAC-SHA512, HKDF-SHA512, and optional SHA-384.

Why this crate exists

libvctrl_sha512 provides a pure Rust, no_std-compatible implementation of several widely used cryptographic algorithms. It is designed to serve as the content-addressing and message-authentication backbone for the larger libvcrtl version control system, while remaining usable as a standalone cryptography crate.

The implementation prioritizes:

• Auditability — no external dependencies and readable, well-structured code.
• Security — constant-time verification, zeroization of intermediate state.
• Performance — aggressive inlining, specialized block processing, and an optional opt_size feature for size-constrained builds.

Module organization

• sha512 — SHA-512 hash function.
• hmac — HMAC keyed-hash message authentication code instantiated with SHA-512.
• hkdf — HKDF key derivation function instantiated with SHA-512.
• utils — shared byte-order and verification helpers.
• sha384 — optional SHA-384 implementation behind the sha384 feature.

The HMAC and HKDF modules are generated using the exported macros impl_hmac! and impl_hkdf!, which allow downstream crates to instantiate these algorithms with other hash functions if needed.

Examples

Compute a SHA-512 digest:

use libvctrl_sha512::Hash;

let digest = Hash::hash(b"hello world");
assert_eq!(digest.len(), 64);

Compute an HMAC-SHA512 authentication tag:

use libvctrl_sha512::HMAC;

let tag = HMAC::mac(b"message", b"secret-key");
assert_eq!(tag.len(), 64);

Re-exports

pub use sha512::Hash;

pub use hmac::HMAC;

pub use hkdf::HKDF;

pub use utils::BLOCKBYTES;

pub use utils::BYTES;

Modules

hkdf

HKDF implementation generated for SHA-512.

hmac

HMAC implementation generated for SHA-512.

sha384

Optional SHA-384 implementation.

sha512

SHA-512 hash function implementation.

utils

Shared byte-order and verification helpers.

Macros

impl_hkdf

Defines an HKDF (HMAC-based Extract-and-Expand Key Derivation Function) type based on the provided hash struct.

impl_hmac

Defines an HMAC (Hash-based Message Authentication Code) type based on the provided hash struct.