IBANValidator

Being a small Swift framework to check validity of IBAN codes. It's based on the the ISO 13616:2007 standard, which defines a checksum process described here.

Installation

Carthage:

1. Add github "timd/IBANValidator" to the Cartfile
2. Run carthage update
3. Add the framework to the Link Binary with Libraries build phase, and add to the Carthage Run Script build phase as per the Carthage documentation.
4. Er...
5. That's it.

Cocoapods:

Not yet. Maybe one day.

Usage

1. Import the framework into the class: import IBANValidator
2. Test the IBAN:

let validIBAN = "AL90208110080000001039531801"

do {
    
    // returns true for valid IBAN, false + error
    // if there's a problem
    let _ = try IBANValidator(iban: validIBAN)
    
    // Validation was successful, carry on
    
} catch let error as IBANValidationError {
    
    // Something is wrong with the IBAN, so handle the error
    print(error)
    
} catch {
    
    // Something else went wrong
    
}

Validation errors

Errors are returned as an IBANValidationError:

public enum IBANValidationError: String, LocalizedError {
    case invalidChecksum = "Invalid checksum"
    case invalidCountryCode = "Invalid country code"
    case invalidLength = "Invalid length"
    case invalidCharacters = "Invalid characters"
}

• invalidChecksum is returned if the checksum calculation fails. This indicates an invalid IBAN.
• invalidCountryCode is returned if the country code does not appear on the list of supported countries (see the list at the top of IBANValidator.swift for the current list)
• invalidLength is returned if the provided IBAN is longer than 34 characters; or exceeds the length defined as the maximum for the country (these differ from country to country)
• invalidCharacters is returned if the provided IBAN contains non-alphanumeric characters. The IBAN standard doesn't support Emoji yet.

Country codes

As a convenience for populating things like picker lists, IBANValidator exposes the countries property which is an Array of Dictionaries containing a two-letter country code as the key. When sorted, this could be used as the data source for a picker to speed up the IBAN data entry and reduce use errors.

Acknowledgements

This framework uses Marcel Kröker's Swift-Big-Integer library, because calculating mod(97) of 34-digit integers makes my head hurt. Sample IBAN numbers for testing can be obtained here.

Disclaimer

Use at your own risk. You probably don't want to rely on this library alone if you're doing anything as dramatic as transferring real money. But it's a good starting point...