Can anyone provide an algorithm to validate a Singaporean FIN?
I know with a Singaporean NRIC I can validate it via modulo 11 and then compare the result to a lookup table but cannot find a similar lookup table for the FIN.
I also do not know for sure if the modulo 11 is the correct method to validate.
I am aware the government sells a algorithm for $400 but maybe someone knows a cheaper way.
Bonus points for c# implementation.
After a little searching around I found a way to validate them. This doesn't neccersarily mean the FIN is valid, just that it falls within a valid range.
I based it on algorithms from http://www.ngiam.net/NRIC/ppframe.htm
I've also included a similar method for checking NRIC because I figure anyone who comes across this and is interested in one is interested in the other as well.
Hope this helps someone!
private static readonly int[] Multiples = { 2, 7, 6, 5, 4, 3, 2 };
public static bool IsNricValid(string nric)
{
if (string.IsNullOrEmpty(nric))
{
return false;
}
// check length
if (nric.Length != 9)
{
return false;
}
int total = 0
, count = 0
, numericNric;
char first = nric[0]
, last = nric[nric.Length - 1];
if (first != 'S' && first != 'T')
{
return false;
}
if (!int.TryParse(nric.Substring(1, nric.Length - 2), out numericNric))
{
return false;
}
while (numericNric != 0)
{
total += numericNric % 10 * Multiples[Multiples.Length - (1 + count++)];
numericNric /= 10;
}
char[] outputs;
if (first == 'S')
{
outputs = new char[] { 'J', 'Z', 'I', 'H', 'G', 'F', 'E', 'D', 'C', 'B', 'A' };
}
else
{
outputs = new char[] { 'G', 'F', 'E', 'D', 'C', 'B', 'A', 'J', 'Z', 'I', 'H' };
}
return last == outputs[total % 11];
}
public static bool IsFinValid(string fin)
{
if (string.IsNullOrEmpty(fin))
{
return false;
}
// check length
if (fin.Length != 9)
{
return false;
}
int total = 0
, count = 0
, numericNric;
char first = fin[0]
, last = fin[fin.Length - 1];
if (first != 'F' && first != 'G')
{
return false;
}
if (!int.TryParse(fin.Substring(1, fin.Length - 2), out numericNric))
{
return false;
}
while (numericNric != 0)
{
total += numericNric % 10 * Multiples[Multiples.Length - (1 + count++)];
numericNric /= 10;
}
char[] outputs;
if (first == 'F')
{
outputs = new char[] { 'X', 'W', 'U', 'T', 'R', 'Q', 'P', 'N', 'M', 'L', 'K' };
}
else
{
outputs = new char[] { 'R', 'Q', 'P', 'N', 'M', 'L', 'K', 'X', 'W', 'U', 'T' };
}
return last == outputs[total % 11];
}
Here's similar code written in JavaScript
var nric = [];
nric.multiples = [ 2, 7, 6, 5, 4, 3, 2 ];
nric.isNricValid = function (theNric) {
if (!theNric || theNric == '')
{
return false;
}
if (theNric.length != 9)
{
return false;
}
var total = 0
, count = 0
, numericNric;
var first = theNric[0]
, last = theNric[theNric.length - 1];
if (first != 'S' && first != 'T')
{
return false;
}
numericNric = theNric.substr(1, theNric.length - 2);
if (isNaN(numericNric)) {
return false
}
while (numericNric != 0)
{
total += (numericNric % 10) * nric.multiples[nric.multiples.length - (1 + count++)];
numericNric /= 10;
numericNric = Math.floor(numericNric);
}
var outputs;
if (first == 'S')
{
outputs = [ 'J', 'Z', 'I', 'H', 'G', 'F', 'E', 'D', 'C', 'B', 'A' ];
}
else
{
outputs = [ 'G', 'F', 'E', 'D', 'C', 'B', 'A', 'J', 'Z', 'I', 'H' ];
}
return last == outputs[total % 11];
}
nric.isFinValid = function(fin)
{
if (!fin || fin == '')
{
return false;
}
if (fin.length != 9)
{
return false;
}
var total = 0
, count = 0
, numericNric;
var first = fin[0]
, last = fin[fin.length - 1];
if (first != 'F' && first != 'G')
{
return false;
}
numericNric = fin.substr(1, fin.length - 2);
if (isNaN(numericNric)) {
return false;
}
while (numericNric != 0)
{
total += (numericNric % 10) * nric.multiples[nric.multiples.length - (1 + count++)];
numericNric /= 10;
numericNric = Math.floor(numericNric);
}
var outputs;
if (first == 'F')
{
outputs = [ 'X', 'W', 'U', 'T', 'R', 'Q', 'P', 'N', 'M', 'L', 'K' ];
}
else
{
outputs = [ 'R', 'Q', 'P', 'N', 'M', 'L', 'K', 'X', 'W', 'U', 'T' ];
}
return last == outputs[total % 11];
}
And again in PHP
function isNricValid ($theNric) {
$multiples = array( 2, 7, 6, 5, 4, 3, 2 );
if (!$theNric || $theNric == '')
{
return false;
}
if (strlen($theNric) != 9)
{
return false;
}
$total = 0;
$count = 0;
$numericNric = 0;
$first = $theNric[0];
$last = $theNric[strlen($theNric) - 1];
if ($first != 'S' && $first != 'T')
{
return false;
}
$numericNric = substr($theNric, 1, strlen($theNric) - 2);
if (!is_numeric ($numericNric)) {
return false;
}
while ($numericNric != 0)
{
$total += ($numericNric % 10) * $multiples[sizeof($multiples) - (1 + $count++)];
$numericNric /= 10;
$numericNric = floor($numericNric);
}
$outputs = '';
if (strcmp($first, "S") == 0)
{
$outputs = array( 'J', 'Z', 'I', 'H', 'G', 'F', 'E', 'D', 'C', 'B', 'A' );
}
else
{
$outputs = array( 'G', 'F', 'E', 'D', 'C', 'B', 'A', 'J', 'Z', 'I', 'H' );
}
return $last == $outputs[$total % 11];
}
function isFinValid ($fin)
{
$multiples = array( 2, 7, 6, 5, 4, 3, 2 );
if (!$fin || $fin == '')
{
return false;
}
if (strlen($fin) != 9)
{
return false;
}
$total = 0;
$count = 0;
$numericNric = 0;
$first = $fin[0];
$last = $fin[strlen($fin) - 1];
if ($first != 'F' && $first != 'G')
{
return false;
}
$numericNric = substr($fin, 1, strlen($fin) - 2);
if (!is_numeric ($numericNric)) {
return false;
}
while ($numericNric != 0)
{
$total += ($numericNric % 10) * $multiples[sizeof($multiples) - (1 + $count++)];
$numericNric /= 10;
$numericNric = floor($numericNric);
}
$outputs = array();
if (strcmp($first, 'F') == 0)
{
$outputs = array( 'X', 'W', 'U', 'T', 'R', 'Q', 'P', 'N', 'M', 'L', 'K' );
}
else
{
$outputs = array( 'R', 'Q', 'P', 'N', 'M', 'L', 'K', 'X', 'W', 'U', 'T' );
}
return $last == $outputs[$total % 11];
}