/**
returns RSA key pair with length $bit_len
*/
function generate_key_pair($bit_len)
{
// generate two primes p and q
$p_len = (int) ($bit_len / 2) + 1;
$q_len = $bit_len - $p_len;
$p = get_prime($p_len);
$q = get_prime($q_len);
// $n - is shared modulus
$n = bi_mul($p, $q);
// generate public ($e) and private ($d) keys
$pq = bi_mul(bi_dec($p), bi_dec($q));
do {
$e = bi_rand($q_len, 'microtime_generator');
} while (!bi_is_zero(bi_dec(bi_gcd($e, $pq))));
$d = bi_invmod($e, $pq);
return array('n' => bi_serialize($n), 'public_key' => bi_serialize($e), 'private_key' => bi_serialize($d));
}
/**
* Calculates $num1 * $num2
*
* @param big_int resource $num1
* @param big_int resource $num2
* @return big_int resource
* @access public
*/
function mul($num1, $num2)
{
return bi_mul($num1, $num2);
}
function bcmul($a, $b)
{
return bi_to_str(bi_mul($a, $b));
}
/*
string bi_base_convert(string $num, int $base_from, int $base_to)
Converts string representation of $num from base $base_from to $base_to
*/
$num = '-12345678900987654321';
echo 'Decimal number [', $num, '] equals to [', bi_base_convert($num, 10, 36), '] by base 36', "<br/>\n";
/*
basic functions
*/
echo '<h3>basic functions</h3>' . "\n";
$c = bi_add($a, $b);
echo '$a + $b = [', bi_to_str($c), "]<br/>\n";
$c = bi_sub($a, $b);
echo '$a - $b = [', bi_to_str($c), "]<br/>\n";
$c = bi_mul($a, $b);
echo '$a * $b = [', bi_to_str($c), "]<br/>\n";
$c = bi_div($a, $b);
echo '$a / $b = [', bi_to_str($c), "]<br/>\n";
$c = bi_mod($a, $b);
echo '$a % $b = [', bi_to_str($c), "]<br/>\n";
$c = bi_abs($a);
echo 'abs($a) = [', bi_to_str($c), "]<br/>\n";
$c = bi_neg($a);
echo 'neg($a) = [', bi_to_str($c), "]<br/>\n";
$c = bi_inc($a);
echo 'inc($a) = [', bi_to_str($c), "]<br/>\n";
$c = bi_dec($a);
echo 'dec($a) = [', bi_to_str($c), "]<br/>\n";
$c = bi_sqr($a);
echo 'sqr($a) = [', bi_to_str($c), "]<br/>\n";
/**
* Multiply two arbitrary precision number
*
* @param string $a The left operand, as a string.
* @param string $b The right operand, as a string.
* @access public
* @return string Returns the result as a string.
*/
public function mul($a, $b)
{
return bi_mul($a, $b);
}
