wolfcrypt

RustCrypto trait implementations backed by wolfCrypt. Swap the backend under your existing RustCrypto code without changing call sites.

Why

wolfCrypt is a FIPS 140-3 validated cryptographic library used in billions of devices across aerospace, automotive, and government products. Choosing wolfcrypt over pure-Rust alternatives gives you:

• FIPS 140-3 — the same validated implementation used in production. Enabling the fips feature alone is not sufficient; FIPS 140-3 validation requires the specific wolfSSL source tree submitted for validation and a commercial license. Contact wolfSSL for a commercial FIPS license and the validated source tree.
• Minimal footprint — #![no_std] (with alloc); compiles to bare-metal RISC-V for embedded hardware security targets (Caliptra, secure elements, automotive MCUs)
• No API changes — your existing digest::Digest, aead::Aead, signature::Signer code keeps working; only the backend changes

Usage

[dependencies]
wolfcrypt = { version = "0.1", features = ["digest", "aead", "signature"] }

SHA-256 via the RustCrypto Digest trait

use wolfcrypt::Sha256;
use digest_trait::Digest;

let mut hasher = Sha256::new();
hasher.update(b"hello ");
hasher.update(b"world");
let digest = hasher.finalize();
// digest: GenericArray<u8, U32>

AES-256-GCM via the RustCrypto Aead trait

use wolfcrypt::Aes256Gcm;
use aead_trait::{Aead, KeyInit};

let key = [0u8; 32];
let nonce = [0u8; 12];
let cipher = Aes256Gcm::new(&key.into());
let ciphertext = cipher.encrypt(&nonce.into(), b"plaintext".as_ref())?;
let plaintext  = cipher.decrypt(&nonce.into(), ciphertext.as_ref())?;

Ed25519 via the RustCrypto Signer/Verifier traits

use wolfcrypt::{Ed25519SigningKey, Ed25519VerifyingKey};
use signature_trait::{Signer, Verifier};

let signing_key = Ed25519SigningKey::generate()?;
let verifying_key: Ed25519VerifyingKey = signing_key.verifying_key();
let signature = signing_key.sign(b"message");
verifying_key.verify(b"message", &signature)?;

The trait crates are renamed in Cargo.toml (digest_trait, aead_trait, signature_trait) to avoid colliding with the digest/aead/signature modules of this crate; downstream code typically imports the upstream names directly.

For algorithms with no RustCrypto trait (HKDF, PBKDF2, AES Key Wrap, classic DH, ECDH, ML-KEM), see the per-module documentation; each provides a bespoke API with method names matching the closest RustCrypto sibling.

How it works

wolfssl-src     Compiles wolfSSL/wolfCrypt C source via the cc crate
      │
wolfcrypt-sys   bindgen FFI; emits cargo cfg flags per compiled algorithm
      │         (wolfssl_aes_gcm, wolfssl_ecc_p384, …)
      │
wolfcrypt-rs    Typed Rust wrapper + C shim for struct field access
      │
wolfcrypt       RustCrypto trait impls (this crate)

Each algorithm is gated behind a Cargo feature and a corresponding cfg flag emitted by wolfcrypt-sys, so unused algorithms are dead-stripped.

References

• wolfcrypt-rs — typed FFI layer this crate is built on
• wolfcrypt-ring-compat — ring API parity alternative for the same backend
• wolfcrypt-tls — TLS client/server using the same backend
• wolfcrypt-conformance — cross-validation suite (NIST CAVP, Wycheproof, RFC vectors); always run after modifying this crate
• RustCrypto traits — upstream trait definitions
• wolfSSL repository
• wolfSSL documentation
• FIPS 140-3 certificate information
• workspace README

Copyright

Copyright (C) 2006-2026 wolfSSL Inc.

License

GPL-3.0-only OR LicenseRef-wolfSSL-commercial.

The underlying wolfSSL C library is licensed under GPL-3.0-or-later with a commercial option available from wolfSSL Inc.