TOTP (Time-Based One-Time Password) Generator

A high-performance and secure TOTP (Time-Based One-Time Password) generator and validator implemented in Go that supports multiple hashing algorithms, including SHA1, SHA256, SHA512, and BLAKE2.

Features

• Efficient HMAC pooling to optimize performance.
• Supports multiple hashing algorithms (SHA1, SHA256, SHA512, BLAKE2, etc.).
• Customizable TOTP settings (digits, time period, skew allowance).
• Secure validation with constant-time comparison.

Installation

go get -u github.com/itpey/totp

Usage

Generate a TOTP Code

package main

import (
	"fmt"
	"time"

	"github.com/itpey/totp"
)

func main() {
	generator := totp.New(totp.Config{
		Secret:    "JBSWY3DPEHPK3PXP", // Base32 encoded secret key
		Algorithm: totp.AlgorithmSHA1,
		Digits:    totp.DigitsSix,
		Period:    30,
		Skew:      1,
	})

	code, err := generator.Generate()
	if err != nil {
		fmt.Println("Error generating TOTP:", err)
		return
	}

	fmt.Println("Generated TOTP Code:", code)
}

Validate a TOTP Code

valid, err := generator.Validate("123456")
if err != nil {
	fmt.Println("Validation error:", err)
} else if valid {
	fmt.Println("TOTP is valid!")
} else {
	fmt.Println("TOTP is invalid!")
}

Configuration

Field	Type	Default	Description
Secret	string	---	Base32 encoded secret key
Algorithm	Algorithm	SHA1	Hashing algorithm
Digits	Digits	6	Number of digits in OTP
Period	int64	30	Time step in seconds
Skew	int64	1	Allowed time skew in periods

Supported Hashing Algorithms

• SHA1
• SHA224
• SHA256
• SHA384
• SHA512
• SHA3-224
• SHA3-256
• SHA3-384
• SHA3-512
• BLAKE2S-256
• BLAKE2B-256
• BLAKE2B-384
• BLAKE2B-512
• MD5

Feedback and Contributions

If you encounter any issues or have suggestions for improvement, please open an issue on GitHub.

We welcome contributions! Fork the repository, make your changes, and submit a pull request.

License

TOTP is open-source software released under the MIT License. You can find a copy of the license in the LICENSE file.

Author

TOTP was created by itpey