Luhn Algorithm Implementation

A Python implementation of the Luhn algorithm for validating credit card numbers.

What is the Luhn Algorithm?

The Luhn algorithm (also known as the modulus 10 or mod 10 algorithm) is a checksum formula used to validate a variety of identification numbers, most commonly credit card numbers. It was designed to protect against accidental errors, not malicious attacks.

Features

• Validates credit card numbers using the Luhn algorithm
• Handles card numbers with spaces and hyphens
• Simple and clean Python implementation

How It Works

The Luhn algorithm follows these steps:

1. Reverse the card number - Start from the rightmost digit
2. Sum odd-positioned digits - Add up every other digit (starting with the rightmost)
3. Double even-positioned digits - Multiply every other digit by 2
4. Handle double-digit results - If doubling results in a number ≥ 10, add the digits together
5. Calculate total - Sum all the processed digits
6. Validate - If the total modulo 10 equals 0, the card number is valid