luhn3 1.0.4

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

Library contains scalar implementations for both decimal and alhpanumeric inputs and vectorized implementation for decimal inputs.

validate isin           time:   [13.136 ns 13.181 ns 13.230 ns]
validate visa           time:   [13.523 ns 13.572 ns 13.627 ns]
validate visa vec       time:   [6.6799 ns 6.7189 ns 6.7671 ns]