hotp

README

HOTP

A minimal go implementation of the HOTP and TOTP algorithms.

Documentation

Index

• func Hotp(key []byte, counter int64, digits int) int
• func Totp(key []byte, counter, epoch, duration int64, digits int) int
• func Truncate(sum []byte, digits int) int

Functions

func Hotp

func Hotp(key []byte, counter int64, digits int) int

Hotp calculates the hotp value for the given counter using the given key. The number of digits for the output code is provided by digits.

func Totp

func Totp(key []byte, counter, epoch, duration int64, digits int) int

Totp calculates a Totp value using the key and number of digits supplied. Counter is the current Unix time, epoch is a relative epoch (can be 0). Duration is how long the code will remain valid (in seconds).

func Truncate

func Truncate(sum []byte, digits int) int

Truncate is the Truncation function for Hotp and Totp code generation defined in RFC 4226. Sum is the 20-byte HMAC-SHA1 output, and digits is the number of digits for the output code.