rust-otp

rust-otp is a modern, flexible Rust library for performing the HMAC-based One-time Password Algorithm (HOTP) as per RFC 4226 and the Time-based One-time Password Algorithm (TOTP) as per RFC 6238.

Features

• Modern Builder API: Easy and readable configuration for HOTP and TOTP.
• Async Support: Native async methods for seamless integration into modern runtimes.
• Enhanced Security: Support for SHA1, SHA256, and SHA512.
• Formatted Output: Direct support for zero-padded strings.
• Zero Dependencies (core): Light-weight and secure.

Installation

Add this to your Cargo.toml:

[dependencies]
rust-otp = "3.0.0"

To enable async support:

rust-otp = { version = "3.0.0", features = ["async"] }

Usage

TOTP (Time-based One-time Password)

use rust_otp::{TOTP, Algorithm};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Standard Google Authenticator configuration (30s step, 6 digits)
    let totp = TOTP::builder()
        .base32_secret("GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ")?
        .digits(6)
        .build()?;

    let code = totp.generate_current_formatted()?;
    println!("Current TOTP code: {}", code);
    Ok(())
}

HOTP (HMAC-based One-time Password)

use rust_otp::{HOTP, Algorithm};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let hotp = HOTP::builder()
        .base32_secret("GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ")?
        .algorithm(Algorithm::SHA256)
        .digits(8)
        .build()?;

    let code = hotp.generate_formatted(1234);
    println!("HOTP code at counter 1234: {}", code);
    Ok(())
}

Async Usage

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let totp = TOTP::builder()
        .base32_secret("GEZDGNBVGY3TQOJQGEZDGNBVGY3TQOJQ")?
        .build()?;

    let code = totp.generate_current_formatted_async().await?;
    println!("Async TOTP code: {}", code);
    Ok(())
}

Running Examples

You can run the provided examples using cargo:

# Run HOTP example
cargo run --example hotp

# Run TOTP example
cargo run --example totp

# Run Async TOTP example
cargo run --example async_totp --features async

License

rust-otp is licensed under the MIT license. The full license is included in this repository in LICENSE.md.