verhoeff.rs

Rust implementation of the Verhoeff checksum algorithm. Detects 100% of single-digit errors and transposition errors in numerical data.

Installation

Add to your Cargo.toml:

[dependencies]
verhoeff = "0.1.0"

Or using cargo-add:

cargo add verhoeff

Quick Start

use verhoeff::{calculate_checksum, validate, validate_aadhaar};

// Calculate checksum digit
let checksum = calculate_checksum("12345678901");
println!("Checksum: {}", checksum); // Output: 0

// Validate number with checksum
let is_valid = validate("123456789010");
println!("Valid: {}", is_valid); // Output: true

// Validate Aadhaar number (12-digit Indian ID)
match validate_aadhaar("123456789010") {
    Ok(true) => println!("Valid Aadhaar"),
    Ok(false) => println!("Invalid checksum"),
    Err(e) => println!("Format error: {}", e),
}

Features

• ✅ 100% Error Detection - Catches all single-digit and adjacent transposition errors
• 🚀 Zero Dependencies - Pure Rust implementation
• ⚡ High Performance - Optimized with const lookup tables
• 🔒 Type Safe - Strong typing with proper error handling
• 📱 Aadhaar Support - Built-in validation for Indian ID numbers

API Reference

Core Functions

Function	Description	Example
calculate_checksum(input: &str) -> u8	Calculate checksum digit	calculate_checksum("12345") returns 1
validate(input: &str) -> bool	Validate number with checksum	validate("123451") returns true
append_checksum(input: &str) -> String	Append checksum to number	append_checksum("12345") returns "123451"

Aadhaar Validation

use verhoeff::validate_aadhaar;

// Returns Result<bool, VerhoeffError>
match validate_aadhaar("123456789010") {
    Ok(valid) => println!("Checksum valid: {}", valid),
    Err(e) => println!("Error: {}", e),
}

Error Types

pub enum VerhoeffError {
    InvalidCharacter(char),      // Non-digit character found
    EmptyInput,                  // Empty string provided
    InvalidAadhaarLength(usize), // Not 12 digits
}

Examples

Run the included example:

cargo run --example basic_usage

Use Cases

• Aadhaar Validation - Indian government ID verification
• Credit Card Numbers - Additional checksum validation
• Invoice Numbers - Prevent transcription errors
• Product Codes - Ensure accurate inventory tracking
• Account Numbers - Reduce payment errors

Contributing

See DEVELOPER.md for development setup, architecture details, and contribution guidelines.

License

MIT License - see LICENSE file for details.

Author

Ankur Pandey (@yuyudhan)