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| <?php | |
| /** | |
| * Name: CodeIgniter RSA library | |
| * Author: Dirk de Man | |
| * dirk_de_man at yahoo . com | |
| * @dirktheman | |
| * | |
| * Created: 05.10.2012 | |
| * | |
| * Description: CodeIgniter RSA library for encrypting and decrypting messages | |
| */ | |
| if ( ! defined('BASEPATH')) exit('No direct script access allowed'); | |
| class Rsa { | |
| /** THE RSA ALGORITHM | |
| * The RSA is an encryption algorithm invented by Rivest, Shamir and Adleman. | |
| * RSA uses a public (open) and a private (secret) key. | |
| * The public key is used to encrypt messages, but only the private key can decrypt them. | |
| * This works the other way around, too: messages encrypted with the private key can only | |
| * be decrypted with the public key. | |
| * | |
| * Generating the keys: | |
| * First we randomly choose two distinct prime numbers, p and q. | |
| * We multiply p and q to get the modulo, n. | |
| * Then calculate public key e where a whole number 1 < e < n which in turn is coprime with (p-1)*(q-1) | |
| * If e is prime it will take less calculations on client side | |
| * Calculate private key d so that e * d mod (p-1)*(q-1) = 1 | |
| * p and q are not stored to remove any evidence which could lead to breaking the cipher | |
| */ | |
| public function generate_keys () | |
| { | |
| global $primes, $maxprimes; | |
| //Primes array | |
| $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); | |
| //Set a random number picker for choosing the primes | |
| mt_srand((double)microtime()*1000000); | |
| $maxprimes = count($primes) - 1; | |
| $p = $primes[mt_rand(0, $maxprimes)]; | |
| while (empty($q) || ($p==$q)) $q = $primes[mt_rand(0, $maxprimes)]; | |
| $n = $p*$q; | |
| $pi = ($p - 1) * ($q - 1); | |
| $e = $this->tofindE($pi, $p, $q); | |
| $d = $this->extend($e, $pi); | |
| $keys = array ($n, $e, $d); | |
| //Return the array $keys[modulo, public key, private key] | |
| return $keys; | |
| } | |
| //function for calculating the modulo | |
| function mo ($g, $l) { | |
| return $g - ($l * floor ($g/$l)); | |
| } | |
| 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 $inverse; | |
| } | |
| function GCD($e, $pi) { | |
| $y = $e; | |
| $x = $pi; | |
| while ($y != 0) { | |
| $w = $this->mo($x , $y); | |
| $x = $y; | |
| $y = $w; | |
| } | |
| return $x; | |
| } | |
| function tofindE($pi) { | |
| global $primes, $maxprimes; | |
| $great = 0; | |
| $cc = mt_rand (0, $maxprimes); | |
| $startcc = $cc; | |
| while ($cc >= 0) { | |
| $se = $primes[$cc]; | |
| $great = $this->GCD($se, $pi); | |
| $cc--; | |
| if ($great == 1) break; | |
| } | |
| if ($great == 0) { | |
| $cc = $startcc + 1; | |
| while ($cc <= $maxprimes) { | |
| $se = $primes[$cc]; | |
| $great = $this->GCD($se, $pi); | |
| $cc++; | |
| if ($great == 1) break; | |
| } | |
| } | |
| return $se; | |
| } | |
| /** ENCRYPTION | |
| * When the public key is known it can be used to encrypt messages. | |
| * The plaintext message, n, is chopped up in blocks of three letters | |
| * The letters in the blocks are transformed to an ASCII code number minus 30 | |
| * The blocks are prepended and appended with a 1 to distinguish them later | |
| * Each individual number is encrypted with the RSA algorithm: block ^E mod N | |
| * The encrypted message, c, is stored in the database | |
| */ | |
| function rsa_encrypt ($m, $e, $n) { | |
| $asci = array (); | |
| for ($i=0; $i<strlen($m); $i+=3) { | |
| $tmpasci="1"; | |
| for ($h=0; $h<3; $h++) { | |
| if ($i+$h <strlen($m)) { | |
| $tmpstr = ord (substr ($m, $i+$h, 1)) - 30; | |
| if (strlen($tmpstr) < 2) { | |
| $tmpstr ="0".$tmpstr; | |
| } | |
| } else { | |
| break; | |
| } | |
| $tmpasci .=$tmpstr; | |
| } | |
| array_push($asci, $tmpasci."1"); | |
| } | |
| //Encrypt individual numbers | |
| $coded = ""; | |
| for ($k=0; $k< count ($asci); $k++) { | |
| $resultmod = $this->powmod($asci[$k], $e, $n); | |
| $coded .= $resultmod." "; | |
| } | |
| //encrypt function returns m = x^d (mod n) | |
| return trim($coded); | |
| } | |
| //Exponentiation function | |
| 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 $accum; | |
| } | |
| /** DECRYPTION | |
| * The encrypted message can only be decrypted with the modulo-private key combination. | |
| * The empty spaces between the blocks are removed and the numbers are stored in an array | |
| * Eacht array item is decrypted with the algorithm block ^D mod N | |
| * Then the prepending and appending number 1s are removed | |
| * After that each ASCII number plus 30 is represented as the corresponding letter. | |
| */ | |
| function rsa_decrypt ($c, $d, $n) { | |
| global $resultd; | |
| global $deencrypt; | |
| //Strip the blank spaces from the ecrypted text and store it in an array | |
| $decryptarray = split(" ", $c); | |
| for ($u=0; $u<count ($decryptarray); $u++) { | |
| if ($decryptarray[$u] == "") { | |
| array_splice($decryptarray, $u, 1); | |
| } | |
| } | |
| //Each number is then decrypted using the RSA formula: block ^D mod N | |
| for ($u=0; $u< count($decryptarray); $u++) { | |
| $resultmod = $this->powmod($decryptarray[$u], $d, $n); | |
| //remove leading and trailing '1' digits | |
| //global $deencrypt; | |
| $deencrypt.= substr ($resultmod, 1, strlen($resultmod)-2); | |
| } | |
| //Each ASCII code number + 30 in the message is represented as its letter | |
| for ($u=0; $u<strlen($deencrypt); $u+=2) { | |
| $resultd .= chr(substr ($deencrypt, $u, 2) + 30); | |
| } | |
| return $resultd; | |
| } | |
| } | |
| /** | |
| * Usage example: | |
| * keys = generate_keys (); | |
| * $message="foo bar"; | |
| * for ($i=32;$i<127;$i++) $message.=chr($i); | |
| * $encoded = rsa_encrypt ($message, $keys[1], $keys[0]); | |
| * $decoded = rsa_decrypt($encoded, $keys[2], $keys[0]); | |
| * echo "<pre><br><i>Test ASCII(32) - ASCII(126):</i>\n"; | |
| * echo "Message: <b>$message</b>\n"; | |
| * echo "Encoded: <b>$encoded</b>\n"; | |
| * echo "Decoded: <b>$decoded</b>\n"; | |
| * | |
| */ | |
| /** | |
| * Copyright (c) Dirk de Man, 2012 | |
| * | |
| * ***DISCLAIMER*** | |
| * This program is free software; you can redistribute it and/or | |
| * modify it under the terms of the GNU General Public License | |
| * as published by the Free Software Foundation; either version 2 | |
| * of the License, or (at your option) any later version. | |
| * | |
| * This program is distributed in the hope that it will be useful, | |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| * GNU General Public License for more details. | |
| * | |
| */ |
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