Crate roka_totp 

Zero-dependency TOTP / HOTP implementation with optional QR code support.

roka-totp is a from-scratch implementation of RFC 6238 (TOTP) and RFC 4226 (HOTP). It carries its own SHA-1, HMAC, and Base32 — no crypto crate is pulled in, no unsafe is used.

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: String = totp.code_at(0); // current 6-digit OTP at UNIX time 0
assert_eq!(code, "282760");

let uri = totp.uri();
assert!(uri.starts_with("otpauth://totp/Acme:alice"));

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).
• otpauth URI build ready for QR pairing.

Structs

Hotp

HOTP — RFC 4226 counter-based one-time password.

Secret

A TOTP / HOTP shared secret (raw bytes).

Totp

TOTP — RFC 6238 time-based one-time password.

TotpBuilder

Builder for Totp.

Enums

Algorithm

Hash algorithm used to derive OTPs.

Error

Errors produced by roka-totp.

Constants

DEFAULT_DIGITS

Default OTP digit count (6).

DEFAULT_STEP

Default time step in seconds (30 — the RFC 6238 standard).