TurkishId

Validator (and a random generator tool) for Turkish Republic's citizen ID numbers. I've decided to give this a shot last night while I was waiting for a download. And Turkish ID numbers were really popular in Turkish social media last week. The Id number is called "T.C. Kimlik No" (Turkish Republic Identity Number). I decided to use English translation to allow easier handling in international projects.

Usage

I wanted the TurkishIdNumber representation to be used anywhere in the code as a value to pass around when using id's allowing to assume an instance is already validated saving you from redundant checks.

When you want to use it as a representation of an ID number:

using TurkishId;
var id = new TurkishIdNumber("12345678901");
// throws ArgumentException when invalid parameter is passed

or if you just want to validate it:

using TurkishId;
bool reallyValid = TurkishIdNumber.IsValid("12345678901");

NuGet package is here: https://www.nuget.org/packages/TurkishId/

Performance

This is probably one of the fastest implementations on .NET. I didn't grind so much on performance but it can easily handle millions of validations per second on my Core i7.

Algorithm

Turkish Republic's ID structure and verification is simple. It's an eleven digit number. If we name each digit as d(n) where leftmost digit is called d1 and the rightmost d11:

d1 > 0

and

d10 = ((d1 + d3 + d5 + d7 + d9) * 7 - (d2 + d4 + d6 + d8)) mod 10

and

d11 = sum(d1..d10) mod 10