Tax ID number

Tax ID numbers vary for each country, and thus may require different algorithms for validation. The example here is for a Norwegian Tax ID with two Modula 11 checksum numbers.

Mask Tax ID
transformation example.anonymizer.transformations.Person_NO
 
 
task MyTaskName
{
	// Anonymize - Mask various fields
	update CUSTOMER Anonymize_CUSTOMER
		// Mask random Norwegian Tax ID
		mask TAX_ID CUSTOMER_TAX_ID
			format "%1$td%1$ty%2$s"
			transform Person_NO
			random-date 1920-01-01 2020-01-01
			random-integer 10000 99999
}	

Notice

transformation "Person_NO" is custom code and location must be registered in top section
a random date and a random 5 digit number will be used for the number
the custom transformation "Person_NO" is used to fix the string in order to validate to Norwegian Tax ID checksum
String format: https://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html

Norwegian Tax ID

DDMMYY - date of birth
XXX - Sequence number where even number identifies a female and odd a male. The first number also identifies century born in.
CC - Modula 11 checksum numbers

Notice the skip routine, in the Norwegian Tax id a tenth of the numbers are invalid because of the Modula 11 checksum may sometimes give two digits.

Person_NO Java code
package example.anonymizer.transformations;
 
import no.esito.anonymizer.ITransformation;
import no.esito.anonymizer.transformations.CreditCard;
 
/**
 * Calculate the check-digits in a Norwegian Tax ID.
 *
 */
public class Person_NO implements ITransformation{
 
	public static final String LABEL = "Person_NO - Norwegian ID generation";
	
	@Override
	public String transform(String input) {
		if(input == null || input.isEmpty())
			return input;
		String s1 = input.substring(0, 9);
		String s2 = personCheckDigit(s1);
		if(s2.length()>2){
			// If invalid number try next
			String s3=""+(Integer.parseInt(input.substring(6, 9))+1002);
			return toPersonNO(input.substring(0, 6)+s3.substring(1, 4)+input.substring(9, 11));
		}
		return s1+s2;
	}
 
	/**
	 * Fix last two digits of a Norwegian Social Security Number
	 * <br>It uses MOD-11 thus it may still create an invalid number  
	 * @param value to be corrected
	 * @return corrected value
	 */
	public static String toPersonNO(String value) {
		String s1 = value.substring(0, 9);
		String s2 = personCheckDigit(s1);
		if(s2.length()>2){
			// If invalid number try next
			String s3=""+(Integer.parseInt(value.substring(6, 9))+1002);
			return toPersonNO(value.substring(0, 6)+s3.substring(1, 4)+value.substring(9, 11));
		}
		return s1+s2;
	}
	
	static String personCheckDigit(String value) {
		int[] d = CreditCard.getDigits(value);
		int k1 = 11 - ((3 * d[0] + 7 * d[1] + 6 * d[2] + 1 * d[3] + 8 * d[4] + 9 * d[5] 
				+ 4 * d[6] + 5 * d[7] + 2 * d[8]) % 11);
		int k2 = 11 - ((5 * d[0] + 4 * d[1] + 3 * d[2] + 2 * d[3] + 7 * d[4] + 6 * d[5] 
				+ 5 * d[6] + 4 * d[7] + 3 * d[8] + 2 * k1) % 11);
		return k1+""+k2;
	}
 
	public static void main(String[] args) {
		String pnr = "02076829716";
		System.out.println("Encode PNR number '" + pnr + "': " + toPersonNO(pnr));
		
	}
 
}
 
	