Use RSA,when run createKey,It always stuck,and then get an error report

Question

I have downloaded the phpseclib0.3.9.zip. When I run this code, the error below occur. I don't know what is the reason.

 <?php
set_include_path(get_include_path() . PATH_SEPARATOR . 'E:/software/PHPRSA');

include 'Crypt/RSA.php';

$rsa = new Crypt_RSA();
extract($rsa->createKey());

$plaintext = 'terrafrost';

$rsa->loadKey($privatekey);
$ciphertext = $rsa->encrypt($plaintext);

$rsa->loadKey($publickey);
echo $rsa->decrypt($ciphertext);
?>  

Here is the error report:

         Call Stack
#   Time    Memory  Function    Location
1   0.0020  131696  {main}( )   ..\test1.php:0
2   0.0290  1276184 Crypt_RSA->createKey( ???, ???, ??? )   ..\test1.php:7
3   27.4046 1356352 Math_BigInteger->randomPrime( object(Math_BigInteger)[8], object(Math_BigInteger)[10], bool )   ..\RSA.php:662

Help be appreciate.

Answer 1

It's timing out.

Generating RSA key pairs is an extremely time consuming operation. In particular, when it's generating the two prime numbers it's creating a whole lot of random numbers and testing each one of them until it finds a prime.

Having bcmath or gmp or even openssl will speed things up a lot.

A few other things you could do to speed things up...

1. define('CRYPT_RSA_SMALLEST_PRIME', 256) could help. That'll make phpseclib use multi-prime RSA. Each key will be 256-bits instead of 512-bits so it'll be faster to generate the prime numbers. The flip side is that your key likely won't be very interoperable with other RSA implementations.

2. You can use the timeout parameter and AJAX to make it take however long it takes. More info: http://phpseclib.sourceforge.net/rsa/examples.html#timeout