58 lines
1.8 KiB
PHP
58 lines
1.8 KiB
PHP
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<?php
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require_once dirname(__FILE__).'/openpgp.php';
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require_once 'Crypt/AES.php';
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class OpenPGP_phpseclib_Crypt {
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public static function decryptSymmetric($pass, $m) {
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foreach($m as $p) {
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if($p instanceof OpenPGP_SymmetricSessionKeyPacket) {
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switch($p->symmetric_algorithm) {
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case 7:
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$cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
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$cipher->setKeyLength(128);
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break;
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case 8:
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$cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
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$cipher->setKeyLength(192);
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break;
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case 9:
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$cipher = new Crypt_AES(CRYPT_AES_MODE_CFB);
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$cipher->setKeyLength(256);
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break;
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}
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if(!$cipher) continue; // Unsupported cipher
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$cipher->setKey($p->s2k->make_key($pass, $cipher->key_size));
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$epacket = self::getEncryptedData($m);
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$padAmount = $cipher->block_size - (strlen($epacket->data) % $cipher->block_size);
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if(strlen($p->encrypted_data) < 1) {
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if($epacket instanceof OpenPGP_IntegrityProtectedDataPacket) {
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$data = substr($cipher->decrypt($epacket->data . str_repeat("\0", $padAmount)), 0, strlen($epacket->data));
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$prefix = substr($data, 0, $cipher->block_size + 2);
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$mdc = substr(substr($data, -22, 22), 2);
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$data = substr($data, $cipher->block_size + 2, -22);
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$mkMDC = hash("sha1", $prefix . $data . "\xD3\x14", true);
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if($mkMDC !== $mdc) return false;
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return OpenPGP_Message::parse($data);
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} else {
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// TODO (resync)
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}
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} else {
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// TODO
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}
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}
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}
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}
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public static function getEncryptedData($m) {
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foreach($m as $p) {
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if($p instanceof OpenPGP_EncryptedDataPacket) return $p;
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}
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throw new Exception("Can only decrypt EncryptedDataPacket");
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}
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}
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