using System;

using System.Text.RegularExpressions;

using System.Linq;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(GenSSN(new DateTime(2010, 2, 1)));

    }

    public static string GenSSN(DateTime yyyy)

    {

        var rex = new Regex(@"^(?<birthdate>(?<day>dd)(?<month>dd)(?<year>dd))(?<individual>dd(?<gender>d))(?<checksum>dd)$");

        string formatOut = "ddMMyy";

        var date = yyyy.ToString(formatOut);

​

        int d1 = Convert.ToInt32(date.Substring(0, 1));

        int d2 = Convert.ToInt32(date.Substring(1, 1));

        int m1 = Convert.ToInt32(date.Substring(2, 1));

        int m2 = Convert.ToInt32(date.Substring(3, 1));

        int y1 = Convert.ToInt32(date.Substring(4, 1));

        int y2 = Convert.ToInt32(date.Substring(5, 1));

        int c1 = 0, c2 = 0, i1 = 0, i2 = 0, i3 = 0;

​

        do{ //Find mathing pairs of c1 and c2

            //c2 need to be equal to last digit.

            var r = new Random();

            var num = yyyy.Year < 2000 ? r.Next(0, 499) : r.Next(500, 900);

            int[] n = num.ToString().ToCharArray().Select(c => Convert.ToInt32(c.ToString())).ToArray();

            i1 = n[0]; i2 = n[1]; i3 = n[2];

​

            //First num (See wiki)

            var v1 = (3 * d1) + (7 * d2) + (6 * m1) + m2 + (8 * y1) + (9 * y2) + (4 * i1) + (5 * i2) + (2 * i3);

            c1 = (v1 % 11) == 0 ? 0 : 11 - (v1 % 11);

​

            //Second/last num (See wiki)

            int v2 = (5 * d1) + (4 * d2) + (3 * m1) + (2 * m2) + (7 * y1) + (6 * y2) + (5 * i1) + (4 * i2) + (3 * i3) + (2 * c1);

            c2 = (v2 % 11) == 0 ? 0 : 11 - (v2 % 11);

​

            //Do until c1 and c2 is lower than 10 and both are true.

            if ((c1 < 10) && (c2 < 10))                    

                break;

​

        } while (true);

​

        var ssn = String.Concat(d1, d2, m1, m2, y1, y2, i1, i2, i3, c1, c2);

        return ssn;

    }

}

​