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Decrypt secret key

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Stephen Paul Weber
2013-01-26 14:55:51 -05:00
parent ae062433b7
commit a56799955f
4 changed files with 48 additions and 4 deletions
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38
lib/openpgp_crypt_aes_tripledes.php
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@@ -30,6 +30,44 @@ class OpenPGP_Crypt_AES_TripleDES {
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);
$cipher->setKey($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)) return NULL;
} else {
$chk = unpack('n', substr($material, -2));
$chk = reset($chk);
$material = substr($material, 0, -2);
$mkChk = 0;
for($i = 0; $i < strlen($material); $i++) {
$mkChk = ($mkChk + ord($material{$i})) % 65536;
}
if($chk != $mkChk) return NULL;
}
$packet->s2k_useage = 0;
$packet->symmetric_algorithm = 0;
$packet->encrypted_data = NULL;
foreach($packet::$secret_key_fields[$packet->algorithm] as $f) {
$length = unpack('n', substr($material, 0, 2)); // in bits
$length = (int)floor((reset($length) + 7) / 8); // in bytes
$packet->key[$f] = substr($material, 2, $length);
$material = substr($material, 2 + $length);
}
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;