function isAadharValid($num) {
settype($num, "string");
$expectedDigit = substr($num, -1);
$actualDigit = CheckSumAadharDigit(substr($num, 0, -1));
return ($expectedDigit == $actualDigit) ? $expectedDigit == $actualDigit : 0;
}
function CheckSumAadharDigit($partial) {
$dihedral = array(
array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9),
array(1, 2, 3, 4, 0, 6, 7, 8, 9, 5),
array(2, 3, 4, 0, 1, 7, 8, 9, 5, 6),
array(3, 4, 0, 1, 2, 8, 9, 5, 6, 7),
array(4, 0, 1, 2, 3, 9, 5, 6, 7, 8),
array(5, 9, 8, 7, 6, 0, 4, 3, 2, 1),
array(6, 5, 9, 8, 7, 1, 0, 4, 3, 2),
array(7, 6, 5, 9, 8, 2, 1, 0, 4, 3),
array(8, 7, 6, 5, 9, 3, 2, 1, 0, 4),
array(9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
);
$permutation = array(
array(0, 1, 2, 3, 4, 5, 6, 7, 8, 9),
array(1, 5, 7, 6, 2, 8, 3, 0, 9, 4),
array(5, 8, 0, 3, 7, 9, 6, 1, 4, 2),
array(8, 9, 1, 6, 0, 4, 3, 5, 2, 7),
array(9, 4, 5, 3, 1, 2, 6, 8, 7, 0),
array(4, 2, 8, 6, 5, 7, 3, 9, 0, 1),
array(2, 7, 9, 3, 8, 0, 6, 4, 1, 5),
array(7, 0, 4, 6, 9, 1, 3, 2, 5, 8)
);
$inverse = array(0, 4, 3, 2, 1, 5, 6, 7, 8, 9);
settype($partial, "string");
$partial = strrev($partial);
$digitIndex = 0;
for ($i = 0; $i < strlen($partial); $i++) {
$digitIndex = $dihedral[$digitIndex][$permutation[($i + 1) % 8][$partial[$i]]];
}
return $inverse[$digitIndex];
}