--- /dev/null
+<?php
+
+require_once dirname(__FILE__).'/openpgp.php';
+@include_once dirname(__FILE__).'/openpgp_crypt_rsa.php';
+@include_once dirname(__FILE__).'/openpgp_mcrypt_wrapper.php';
+@include_once 'Crypt/AES.php';
+@include_once 'Crypt/TripleDES.php';
+require_once 'Crypt/Random.php'; // part of phpseclib is absolutely required
+
+class OpenPGP_Crypt_Symmetric {
+ public static function encrypt($passphrases_and_keys, $message, $symmetric_algorithm=9) {
+ list($cipher, $key_bytes, $key_block_bytes) = self::getCipher($symmetric_algorithm);
+ if(!$cipher) throw new Exception("Unsupported cipher");
+ $prefix = crypt_random_string($key_block_bytes);
+ $prefix .= substr($prefix, -2);
+
+ $key = crypt_random_string($key_bytes);
+ $cipher->setKey($key);
+
+ $to_encrypt = $prefix . $message->to_bytes();
+ $mdc = new OpenPGP_ModificationDetectionCodePacket(hash('sha1', $to_encrypt . "\xD3\x14", true));
+ $to_encrypt .= $mdc->to_bytes();
+ $encrypted = array(new OpenPGP_IntegrityProtectedDataPacket($cipher->encrypt($to_encrypt)));
+
+ if(!is_array($passphrases_and_keys) && !($passphrases_and_keys instanceof IteratorAggregate)) {
+ $passphrases_and_keys = (array)$passphrases_and_keys;
+ }
+
+ foreach($passphrases_and_keys as $pass) {
+ if($pass instanceof OpenPGP_PublicKeyPacket) {
+ if(!in_array($pass->algorithm, array(1,2,3))) throw new Exception("Only RSA keys are supported.");
+ $crypt_rsa = new OpenPGP_Crypt_RSA($pass);
+ $rsa = $crypt_rsa->public_key();
+ $rsa->setEncryptionMode(CRYPT_RSA_ENCRYPTION_PKCS1);
+ $esk = $rsa->encrypt(chr($symmetric_algorithm) . $key . pack('n', self::checksum($key)));
+ $esk = pack('n', OpenPGP::bitlength($esk)) . $esk;
+ array_unshift($encrypted, new OpenPGP_AsymmetricSessionKeyPacket($pass->algorithm, $pass->fingerprint(), $esk));
+ } else if(is_string($pass)) {
+ $s2k = new OpenPGP_S2K(crypt_random_string(10));
+ $cipher->setKey($s2k->make_key($pass, $key_bytes));
+ $esk = $cipher->encrypt(chr($symmetric_algorithm) . $key);
+ array_unshift($encrypted, new OpenPGP_SymmetricSessionKeyPacket($s2k, $esk, $symmetric_algorithm));
+ }
+ }
+
+ return new OpenPGP_Message($encrypted);
+ }
+
+ public static function decryptSymmetric($pass, $m) {
+ $epacket = self::getEncryptedData($m);
+
+ foreach($m as $p) {
+ if($p instanceof OpenPGP_SymmetricSessionKeyPacket) {
+ if(strlen($p->encrypted_data) > 0) {
+ list($cipher, $key_bytes, $key_block_bytes) = self::getCipher($p->symmetric_algorithm);
+ if(!$cipher) continue;
+ $cipher->setKey($p->s2k->make_key($pass, $key_bytes));
+
+ $padAmount = $key_block_bytes - (strlen($p->encrypted_data) % $key_block_bytes);
+ $data = substr($cipher->decrypt($p->encrypted_data . str_repeat("\0", $padAmount)), 0, strlen($p->encrypted_data));
+ $decrypted = self::decryptPacket($epacket, ord($data{0}), substr($data, 1));
+ } else {
+ list($cipher, $key_bytes, $key_block_bytes) = self::getCipher($p->symmetric_algorithm);
+ $decrypted = self::decryptPacket($epacket, $p->symmetric_algorithm, $p->s2k->make_key($pass, $key_bytes));
+ }
+
+ if($decrypted) return $decrypted;
+ }
+ }
+
+ return NULL; /* If we get here, we failed */
+ }
+
+ public static function decryptSecretKey($pass, $packet) {
+ $packet = clone $packet; // Do not mutate orinigal
+
+ list($cipher, $key_bytes, $key_block_bytes) = self::getCipher($packet->symmetric_algorithm);
+ if(!$cipher) throw new Exception("Unsupported cipher");
+ $cipher->setKey($packet->s2k->make_key($pass, $key_bytes));
+ $cipher->setIV(substr($packet->encrypted_data, 0, $key_block_bytes));
+ $material = $cipher->decrypt(substr($packet->encrypted_data, $key_block_bytes));
+
+ if($packet->s2k_useage == 254) {
+ $chk = substr($material, -20);
+ $material = substr($material, 0, -20);
+ if($chk != hash('sha1', $material, true)) return NULL;
+ } else {
+ $chk = unpack('n', substr($material, -2));
+ $chk = reset($chk);
+ $material = substr($material, 0, -2);
+
+ $mkChk = self::checksum($material);
+ if($chk != $mkChk) return NULL;
+ }
+
+ $packet->s2k_useage = 0;
+ $packet->symmetric_algorithm = 0;
+ $packet->encrypted_data = NULL;
+ $packet->input = $material;
+ $packet->key_from_input();
+ unset($packet->input);
+ return $packet;
+ }
+
+ public static function decryptPacket($epacket, $symmetric_algorithm, $key) {
+ list($cipher, $key_bytes, $key_block_bytes) = self::getCipher($symmetric_algorithm);
+ if(!$cipher) return NULL;
+ $cipher->setKey($key);
+
+ if($epacket instanceof OpenPGP_IntegrityProtectedDataPacket) {
+ $padAmount = $key_block_bytes - (strlen($epacket->data) % $key_block_bytes);
+ $data = substr($cipher->decrypt($epacket->data . str_repeat("\0", $padAmount)), 0, strlen($epacket->data));
+ $prefix = substr($data, 0, $key_block_bytes + 2);
+ $mdc = substr(substr($data, -22, 22), 2);
+ $data = substr($data, $key_block_bytes + 2, -22);
+
+ $mkMDC = hash("sha1", $prefix . $data . "\xD3\x14", true);
+ if($mkMDC !== $mdc) return false;
+
+ try {
+ $msg = OpenPGP_Message::parse($data);
+ } catch (Exception $ex) { $msg = NULL; }
+ if($msg) return $msg; /* Otherwise keep trying */
+ } else {
+ // No MDC mean decrypt with resync
+ $iv = substr($epacket->data, 2, $key_block_bytes);
+ $edata = substr($epacket->data, $key_block_bytes + 2);
+ $padAmount = $key_block_bytes - (strlen($edata) % $key_block_bytes);
+
+ $cipher->setIV($iv);
+ $data = substr($cipher->decrypt($edata . str_repeat("\0", $padAmount)), 0, strlen($edata));
+
+ try {
+ $msg = OpenPGP_Message::parse($data);
+ } catch (Exception $ex) { $msg = NULL; }
+ if($msg) return $msg; /* Otherwise keep trying */
+ }
+
+ return NULL; /* Failed */
+ }
+
+ public static function getCipher($algo) {
+ $cipher = NULL;
+ switch($algo) {
+ case 2:
+ if(class_exists('Crypt_TripleDES')) {
+ $cipher = new Crypt_TripleDES(CRYPT_DES_MODE_CFB);
+ $key_bytes = 24;
+ $key_block_bytes = 8;
+ }
+ break;
+ case 3:
+ if(defined('MCRYPT_CAST_128')) {
+ $cipher = new MCryptWrapper(MCRYPT_CAST_128);
+ }
+ break;
+ case 7:
+ if(class_exists('Crypt_AES')) {
+ $cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
+ $cipher->setKeyLength(128);
+ }
+ break;
+ case 8:
+ if(class_exists('Crypt_AES')) {
+ $cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
+ $cipher->setKeyLength(192);
+ }
+ break;
+ case 9:
+ if(class_exists('Crypt_AES')) {
+ $cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
+ $cipher->setKeyLength(256);
+ }
+ break;
+ }
+ if(!$cipher) return array(NULL, NULL, NULL); // Unsupported cipher
+ if(!isset($key_bytes)) $key_bytes = $cipher->key_size;
+ if(!isset($key_block_bytes)) $key_block_bytes = $cipher->block_size;
+ return array($cipher, $key_bytes, $key_block_bytes);
+ }
+
+ public static function getEncryptedData($m) {
+ foreach($m as $p) {
+ if($p instanceof OpenPGP_EncryptedDataPacket) return $p;
+ }
+ throw new Exception("Can only decrypt EncryptedDataPacket");
+ }
+
+ public static function checksum($s) {
+ $mkChk = 0;
+ for($i = 0; $i < strlen($s); $i++) {
+ $mkChk = ($mkChk + ord($s{$i})) % 65536;
+ }
+ return $mkChk;
+ }
+}
projects / friendica-addons.git / blobdiff