Crate hqc_kem 

Pure Rust implementation of HQC-KEM (NIST FIPS 207).

HQC is a code-based Key Encapsulation Mechanism using quasi-cyclic codes over the ring Z_2[X]/(X^n-1). Uses concatenated Reed-Solomon + Reed-Muller error correction with Fujisaki-Okamoto transform for IND-CCA2 security.

Usage

use hqc_kem::{Hqc128, HqcKem};

let mut rng = rand::rng();
let (ek, dk) = Hqc128::generate_key(&mut rng);
let (ct, ss1) = ek.encapsulate(&mut rng);
let ss2 = dk.decapsulate(&ct);
assert_eq!(ss1, ss2);

Security Levels

• Hqc128 / hqc128: NIST Level 1 (128-bit security)
• Hqc192 / hqc192: NIST Level 3 (192-bit security)
• Hqc256 / hqc256: NIST Level 5 (256-bit security)

Features

• kgen: Key generation (default)
• ecap: Encapsulation (default)
• dcap: Decapsulation (default)
• kem: RustCrypto kem 0.3 trait implementations
• pkcs8: PKCS#8 key encoding/decoding (requires alloc)
• pem: PEM encoding (enables pkcs8/pem)
• alloc: Vec/Box conversions and PKCS#8 encoding
• serde: Serde serialization support
• std: Standard library (default; enables runtime CPU feature detection)

The core KEM (kgen/ecap/dcap) is no_std and performs no heap allocation.

Modules

hqc128

HQC-128: NIST Level 1 security (128-bit).

hqc192

HQC-192: NIST Level 3 security (192-bit).

hqc256

HQC-256: NIST Level 5 security (256-bit).

Structs

Ciphertext

HQC ciphertext.

DecapsulationKey

HQC decapsulation key (secret key).

EncapsulationKey

HQC encapsulation key (public key).

Hqc128Params

HQC-128 parameter marker (NIST Level 1, 128-bit security).

Hqc192Params

HQC-192 parameter marker (NIST Level 3, 192-bit security).

Hqc256Params

HQC-256 parameter marker (NIST Level 5, 256-bit security).

HqcKem

HQC Key Encapsulation Mechanism parameterized by security level.

SharedSecret

HQC shared secret.

Enums

Error

Errors that can occur during HQC operations.

Traits

HqcParams

Trait defining an HQC parameter set.

Type Aliases

Hqc128

HQC-128 KEM (NIST Level 1).

Hqc192

HQC-192 KEM (NIST Level 3).

Hqc256

HQC-256 KEM (NIST Level 5).