Proyectos de Subversion Moodle

<?php

declare(strict_types=1);


class rsa {
    /**
     * 
     * @var array
     */
    private $primes;
    
    /**
     * 
     * @var int
     */
    private $maxprimes;
    
    /**
     * 
     * @var Rsa
     */
    private static $_instance;
    
    /**
     * 
     * @var int
     */
    private $n;
    
    /**
     *
     * @var int
     */
    private $e;
    
    /**
     *
     * @var int
     */
    private $d;
    
    public function __construct()
    {
        /*random generator seed */
        //mt_srand((double)microtime()*1000000);
        mt_srand((int)microtime()*1000000);
        /*
         * Prime numbers table
         * 570 prime numbers (Array can not be be enlarged)
         * 4507, 4513 is the smallest and 9521, 9533 is the largest pair
         * Still have no time to find why 9521, 9533 is the largest - sorry :)
         */
        $this->primes = array (4507, 4513, 4517, 4519, 4523, 4547, 4549, 4561, 4567, 4583, 4591, 4597,
            4603, 4621, 4637, 4639, 4643, 4649, 4651, 4657, 4663, 4673, 4679, 4691, 4703, 4721, 4723, 4729, 4733, 4751,
            4759, 4783, 4787, 4789, 4793, 4799, 4801, 4813, 4817, 4831, 4861, 4871, 4877, 4889, 4903, 4909, 4919, 4931,
            4933, 4937, 4943, 4951, 4957, 4967, 4969, 4973, 4987, 4993, 4999, 5003, 5009, 5011, 5021, 5023, 5039, 5051,
            5059, 5077, 5081, 5087, 5099, 5101, 5107, 5113, 5119, 5147, 5153, 5167, 5171, 5179, 5189, 5197, 5209, 5227,
            5231, 5233, 5237, 5261, 5273, 5279, 5281, 5297, 5303, 5309, 5323, 5333, 5347, 5351, 5381, 5387, 5393, 5399,
            5407, 5413, 5417, 5419, 5431, 5437, 5441, 5443, 5449, 5471, 5477, 5479, 5483, 5501, 5503, 5507, 5519, 5521,
            5527, 5531, 5557, 5563, 5569, 5573, 5581, 5591, 5623, 5639, 5641, 5647, 5651, 5653, 5657, 5659, 5669, 5683,
            5689, 5693, 5701, 5711, 5717, 5737, 5741, 5743, 5749, 5779, 5783, 5791, 5801, 5807, 5813, 5821, 5827, 5839,
            5843, 5849, 5851, 5857, 5861, 5867, 5869, 5879, 5881, 5897, 5903, 5923, 5927, 5939, 5953, 5981, 5987, 6007,
            6011, 6029, 6037, 6043, 6047, 6053, 6067, 6073, 6079, 6089, 6091, 6101, 6113, 6121, 6131, 6133, 6143, 6151,
            6163, 6173, 6197, 6199, 6203, 6211, 6217, 6221, 6229, 6247, 6257, 6263, 6269, 6271, 6277, 6287, 6299, 6301,
            6311, 6317, 6323, 6329, 6337, 6343, 6353, 6359, 6361, 6367, 6373, 6379, 6389, 6397, 6421, 6427, 6449, 6451,
            6469, 6473, 6481, 6491, 6521, 6529, 6547, 6551, 6553, 6563, 6569, 6571, 6577, 6581, 6599, 6607, 6619, 6637,
            6653, 6659, 6661, 6673, 6679, 6689, 6691, 6701, 6703, 6709, 6719, 6733, 6737, 6761, 6763, 6779, 6781, 6791,
            6793, 6803, 6823, 6827, 6829, 6833, 6841, 6857, 6863, 6869, 6871, 6883, 6899, 6907, 6911, 6917, 6947, 6949,
            6959, 6961, 6967, 6971, 6977, 6983, 6991, 6997, 7001, 7013, 7019, 7027, 7039, 7043, 7057, 7069, 7079, 7103,
            7109, 7121, 7127, 7129, 7151, 7159, 7177, 7187, 7193, 7207, 7211, 7213, 7219, 7229, 7237, 7243, 7247, 7253,
            7283, 7297, 7307, 7309, 7321, 7331, 7333, 7349, 7351, 7369, 7393, 7411, 7417, 7433, 7451, 7457, 7459, 7477,
            7481, 7487, 7489, 7499, 7507, 7517, 7523, 7529, 7537, 7541, 7547, 7549, 7559, 7561, 7573, 7577, 7583, 7589,
            7591, 7603, 7607, 7621, 7639, 7643, 7649, 7669, 7673, 7681, 7687, 7691, 7699, 7703, 7717, 7723, 7727, 7741,
            7753, 7757, 7759, 7789, 7793, 7817, 7823, 7829, 7841, 7853, 7867, 7873, 7877, 7879, 7883, 7901, 7907, 7919,
            7927, 7933, 7937, 7949, 7951, 7963, 7993, 8009, 8011, 8017, 8039, 8053, 8059, 8069, 8081, 8087, 8089, 8093,
            8101, 8111, 8117, 8123, 8147, 8161, 8167, 8171, 8179, 8191, 8209, 8219, 8221, 8231, 8233, 8237, 8243, 8263,
            8269, 8273, 8287, 8291, 8293, 8297, 8311, 8317, 8329, 8353, 8363, 8369, 8377, 8387, 8389, 8419, 8423, 8429,
            8431, 8443, 8447, 8461, 8467, 8501, 8513, 8521, 8527, 8537, 8539, 8543, 8563, 8573, 8581, 8597, 8599, 8609,
            8623, 8627, 8629, 8641, 8647, 8663, 8669, 8677, 8681, 8689, 8693, 8699, 8707, 8713, 8719, 8731, 8737, 8741,
            8747, 8753, 8761, 8779, 8783, 8803, 8807, 8819, 8821, 8831, 8837, 8839, 8849, 8861, 8863, 8867, 8887, 8893,
            8923, 8929, 8933, 8941, 8951, 8963, 8969, 8971, 8999, 9001, 9007, 9011, 9013, 9029, 9041, 9043, 9049, 9059,
            9067, 9091, 9103, 9109, 9127, 9133, 9137, 9151, 9157, 9161, 9173, 9181, 9187, 9199, 9203, 9209, 9221, 9227,
            9239, 9241, 9257, 9277, 9281, 9283, 9293, 9311, 9319, 9323, 9337, 9341, 9343, 9349, 9371, 9377, 9391, 9397,
            9403, 9413, 9419, 9421, 9431, 9433, 9437, 9439, 9461, 9463, 9467, 9473, 9479, 9491, 9497, 9511, 9521, 9533);
        
        $this->maxprimes = count($this->primes) - 1;
        
       
    }
    
    /**
     * 
     * @param int $n
     * @param int $d
     * @param int $e
     */
    public function setKeys($n, $d, $e) 
    {
        $this->n = $n;
        $this->d = $d;
        $this->e = $e;
    }
    
    /*
     Function for generating keys. Return array where
     $array[0] -> modulo N
     $array[1] ->  key E
     $array[2] ->  key D
     Public key pair is N and E
     Private key pair is N and D
     */
    public function generateKeys()
    {
        list($usec, $sec) = explode(' ', microtime());
        $seed = intval($sec + ((float) $usec * 100000));
        mt_srand($seed, MT_RAND_MT19937);
        

        $e = 0;
        $q = 0;
        $q = 0;
        
        //class-ify: global $primes, $maxprimes;
        while (empty($e) || empty($d)) {
            /* finding 2 small prime numbers $p and $q
             $p and $q must be different*/
            $p = $this->primes[mt_rand(0, $this->maxprimes)];
            while (empty($q) || ($p==$q)) {
                $q = $this->primes[mt_rand(0, $this->maxprimes)];
            }
            //second part of  and  pairs - N
            $n = $p*$q;
            
            //$pi (we need it to calculate D and E)
            $pi = ($p - 1) * ($q - 1);
            
            // Public key  E
            $e = $this->tofindE($pi, $p, $q);
            
            // Private key D
            $d = $this->extend($e, $pi);
            
            $keys = array ('n' => $n, 'd' => $d, 'e' => $e);
        }
        return $keys;
    }
    
    /* modulus function */
    private function mo($g, $l) 
    {
        $result = $g - ($l * floor ($g/$l));
        
        return $result;
    }
    
    /*
     * Standard method of calculating D
     * D = E-1 (mod N)
     * It's presumed D will be found in less then 16 iterations
     */
    private function extend($Ee, $Epi) {
        $u1 = 1;
        $u2 = 0;
        $u3 = $Epi;
        $v1 = 0;
        $v2 = 1;
        $v3 = $Ee;
        while ($v3 != 0) {
            $qq = floor($u3/$v3);
            $t1 = $u1 - $qq * $v1;
            $t2 = $u2 - $qq * $v2;
            $t3 = $u3 - $qq * $v3;
            $u1 = $v1;
            $u2 = $v2;
            $u3 = $v3;
            $v1 = $t1;
            $v2 = $t2;
            $v3 = $t3;
            $z = 1;
        }
        $uu = $u1;
        $vv = $u2;
        if ($vv < 0) {
            $inverse = $vv + $Epi;
        } else {
            $inverse = $vv;
        }
        return $inverse;
    }
    
    /* This function return Greatest Common Divisor for $e and $pi numbers */
    private function GCD($e, $pi) 
    {
        $y = $e;
        $x = $pi;
        while ($y != 0) {
            $w =  $this->mo($x , $y);
            $x = $y;
            $y = $w;
        }
        return $x;
    }
    
    /*function for calculating E under conditions:
     GCD(N, E) = 1 and 1<E<N
     If each test E is prime, there will be much less loops in that fuction
     and smaller E means less JS calculations on client side */
    /*
     * Calculating E under conditions:
     * GCD(N, E) = 1 and 1<E<N
     * If E is prime, there will be fewer loops in the function.
     * Smaller E also means reduced JS calculations on client side.
     */
    private function tofindE($pi) 
    {
        //class-ify: global $primes, $maxprimes;
        $great = 0;
        $cc = mt_rand (0, $this->maxprimes);
        $startcc = $cc;
        while ($cc >= 0) {
            $se = $this->primes[$cc];
            $great = $this->GCD($se, $pi);
            $cc--;
            if ($great == 1) { break; }
        }
        if ($great == 0) {
            $cc = $startcc + 1;
            while ($cc <= $this->maxprimes) {
                $se = $this->primes[$cc];
                $great = $this->GCD($se, $pi);
                $cc++;
                if ($great == 1) { break; }
            }
        }
        return $se;
    }
    
    /*
     * ENCRYPT function returns
     *, X = M^E (mod N)
     * Please check http://www.ge.kochi-ct.ac.jp/cgi-bin-takagi/calcmodp
     * and Flash5 RSA .fla by R.Vijay <rveejay0 <at> hotmail <dot> com> at
     * http://www.digitalillusion.co.in/lab/rsaencyp.htm
     * It is one of the simplest examples for binary RSA calculations
     *
     * Each letter in the message is represented as its ASCII code number - 30
     * 3 letters in each block with 1 in the beginning and end.
     * For example string
     *, AAA
     * will become
     *, 13535351 (A = ASCII 65-30 = 35)
     * we can build these blocks because the smalest prime available is 4507
     *, 4507^2 = 20313049
     * This means that
     *, 1. Modulo N will always be < 19999991
     *, 2. Letters > ASCII 128 must not occur in plain text message
     */
    
    public function encrypt($m)
    {
        $m = strval($m);
        
        $asci = array ();
        for ($i=0, $max = strlen($m); $i<$max; $i+=3) {
            $tmpasci='1';
            for ($h=0; $h<3; $h++) 
            {
                if ($i+$h <strlen($m)) {
                    $tmpstr = strval((ord (substr ($m, $i+$h, 1)) - 30));
                    if (strlen($tmpstr) < 2) {
                        $tmpstr ='0'.$tmpstr;
                    }
                } else {
                    break;
                }
                $tmpasci .=$tmpstr;
            }
            array_push($asci, $tmpasci.'1');
        }
        //Each number is then encrypted using the RSA formula: block ^E mod N
        $coded = null;
        for ($k=0, $max = count($asci) ; $k < $max; $k++) 
        {
            $resultmod = $this->powmod($asci[$k], $this->e, $this->n);
            $coded .= $resultmod." ";
        }
        return strval($coded);
    }
    
    /*Russian Peasant method for exponentiation */
    private function powmod($base, $exp, $modulus) 
    {
        $accum = 1;
        $i = 0;
        $basepow2 = $base;
        while (($exp >> $i)>0) {
            if ((($exp >> $i) & 1) == 1) {
                $accum = $this->mo(($accum * $basepow2) , $modulus);
            }
            $basepow2 = $this->mo(($basepow2 * $basepow2) , $modulus);
            $i++;
        }
        return $accum;
    }
    
    /*
     ENCRYPT function returns
     M = X^D (mod N)
     */
    public function decrypt($c) {
        $c = strval($c); 
        
        //Strip the blank spaces from the ecrypted text and store it in an array
        $decryptarray = explode(' ', $c);
        for ($u=0; $u<count ($decryptarray); $u++) 
        {
            if ($decryptarray[$u] == '') {
                array_splice($decryptarray, $u, 1);
            }
        }
        //Each number is then decrypted using the RSA formula: block ^D mod N
        $deencrypt = '';
        for ($u=0, $max = count($decryptarray); $u < $max; $u++) 
        {
            $resultmod = strval($this->powmod($decryptarray[$u], $this->d, $this->n));
            //remove leading and trailing '1' digits
            $deencrypt.= substr ($resultmod, 1, strlen($resultmod)-2);
        }
        //Each ASCII code number + 30 in the message is represented as its letter
        $resultd = '';
        for ($u=0; $u<strlen($deencrypt); $u+=2) {
            $resultd .= chr(substr ($deencrypt, $u, 2) + 30);
        }
        return $resultd;
    }
}

?>