luhn3 1.0.2

A Luhn validation library
Documentation

Validates strings and computes check digits using the Luhn algorithm.

This is a fast, allocation and panic free crate for computing and validating Luhn checksum for decimal and alpha numeric sequences. This is my crate. There are many like it, but this one is mine.

It's not a great checksum, but it's used in a bunch of places:

  • credit card numbers
  • International Securities Identification Number (ISIN) codes
  • International Mobile Equipment Identity (IMEI) codes
  • Canadian Social Insurance Numbers

More information is available on wikipedia.

Usage

Add luhn3 under [dependencies] in your Cargo.toml:

[dependencies]
luhn3 = "1.0"

Most of the CC numbers use Luhn checksum:

// Visa
luhn3::valid(b"4111111111111111"); // true

// MasterCard
luhn3::valid(b"5555555555554444"); // true

// Invalid Visa
luhn3::valid(b"4111111111111121"); // false

Library also allows to calculate a checksum if missing:

// Take off the checksum from American Express card number
let (&check, body) = b"378282246310005".split_last().unwrap();
// and recalculate it
luhn3::checksum(body); // Some(b'5')

This library provides two sets of operation: [decimal] and [alphanum].

  • decimal operates on sequences composed of decimal numbers only, such as credit card numbers or IMEI codes
  • alphanum operates on sequences composed of decimal numbers and capital latin letters, such as ISIN or NSIN

no_std

Crate doesn't use std

Performance

validate isin           time:   [20.908 ns 20.971 ns 21.040 ns]
validate visa           time:   [17.241 ns 17.289 ns 17.341 ns]