roka-totp

Zero-dependency TOTP / HOTP implementation for Rust.

Implements RFC 6238 (TOTP) and RFC 4226 (HOTP). Brings its own SHA-1, HMAC-SHA1, and Base32 — no crypto crate is pulled in, no unsafe is used.

Highlights

• Zero external crate dependencies. std only.
• No unsafe.
• RFC test vectors verified — SHA-1 (RFC 3174), HMAC (RFC 2202), HOTP (RFC 4226 Appendix D), TOTP (RFC 6238 Appendix B).
• Type-safe API — Secret newtype, Algorithm enum, builder pattern.
• otpauth URI build ready for QR pairing.

Quick start

use roka_totp::{Totp, Secret};

let secret = Secret::from_base32("JBSWY3DPEHPK3PXP")?;
let totp = Totp::builder(secret)
    .issuer("Acme")
    .account("alice@example.com")
    .build();

let code = totp.code_now();        // current OTP, e.g. "847529"
let uri = totp.uri();              // otpauth://totp/Acme:alice... for QR pairing

// Verify a user-entered code against the current window ± 1 step
match totp.verify(&user_input, totp_unix_now(), 1) {
    Some(offset) => println!("ok (offset {offset} windows)"),
    None => println!("reject"),
}
# fn totp_unix_now() -> u64 { 0 }
# let user_input = String::new();
# Ok::<(), roka_totp::Error>(())

When to use this crate

• You want minimal supply-chain risk for your authentication path. roka-totp has zero transitive dependencies — anyone can audit the whole code path from base32 secret to 6-digit code in an afternoon.
• You're targeting embedded / WASM / no-std-ish environments where pulling in RustCrypto + serde is excessive.
• You want QR generation built in — pair with roka-qr and ship a complete 2FA stack with no other deps.

Performance

Indicative numbers on M2 (release); see BUDGETS.md:

Regression gates live in tests/perf_gate.rs.

Roadmap

• 0.1.0 — current API surface (SHA-1 only).
• 0.2.0 — Algorithm::Sha256 / Algorithm::Sha512 (otpauth URI standard).
• 0.2.x — Totp::from_uri parsing.
• Later — no_std + alloc support.

License

Dual-licensed under Apache 2.0 or MIT, at your option.

Part of the roka project by GOLIA Inc.