+++ /dev/null
-<?php
-
-/*
- * PHP Encryption Library
- * Copyright (c) 2014, Taylor Hornby
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright notice,
- * this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
- * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- * POSSIBILITY OF SUCH DAMAGE.
- */
-
-/*
- * Web: https://defuse.ca/secure-php-encryption.htm
- * GitHub: https://github.com/defuse/php-encryption
- *
- * WARNING: This encryption library is not a silver bullet. It only provides
- * symmetric encryption given a uniformly random key. This means you MUST NOT
- * use an ASCII string like a password as the key parameter, it MUST be
- * a uniformly random key generated by CreateNewRandomKey(). If you want to
- * encrypt something with a password, apply a password key derivation function
- * like PBKDF2 or scrypt with a random salt to generate a key.
- *
- * WARNING: Error handling is very important, especially for crypto code!
- *
- * How to use this code:
- *
- * Generating a Key
- * ----------------
- * try {
- * $key = self::CreateNewRandomKey();
- * // WARNING: Do NOT encode $key with bin2hex() or base64_encode(),
- * // they may leak the key to the attacker through side channels.
- * } catch (CryptoTestFailedException $ex) {
- * die('Cannot safely create a key');
- * } catch (CannotPerformOperationException $ex) {
- * die('Cannot safely create a key');
- * }
- *
- * Encrypting a Message
- * --------------------
- * $message = "ATTACK AT DAWN";
- * try {
- * $ciphertext = self::Encrypt($message, $key);
- * } catch (CryptoTestFailedException $ex) {
- * die('Cannot safely perform encryption');
- * } catch (CannotPerformOperationException $ex) {
- * die('Cannot safely perform decryption');
- * }
- *
- * Decrypting a Message
- * --------------------
- * try {
- * $decrypted = self::Decrypt($ciphertext, $key);
- * } catch (InvalidCiphertextException $ex) { // VERY IMPORTANT
- * // Either:
- * // 1. The ciphertext was modified by the attacker,
- * // 2. The key is wrong, or
- * // 3. $ciphertext is not a valid ciphertext or was corrupted.
- * // Assume the worst.
- * die('DANGER! DANGER! The ciphertext has been tampered with!');
- * } catch (CryptoTestFailedException $ex) {
- * die('Cannot safely perform encryption');
- * } catch (CannotPerformOperationException $ex) {
- * die('Cannot safely perform decryption');
- * }
- */
-
-/*
- * Raised by Decrypt() when one of the following conditions are met:
- * - The key is wrong.
- * - The ciphertext is invalid or not in the correct format.
- * - The attacker modified the ciphertext.
- */
-class InvalidCiphertextException extends Exception {}
-/* If you see these, it means it is NOT SAFE to do encryption on your system. */
-class CannotPerformOperationException extends Exception {}
-class CryptoTestFailedException extends Exception {}
-
-final class Crypto
-{
- // Ciphertext format: [____HMAC____][____IV____][____CIPHERTEXT____].
-
- /* DO NOT CHANGE THESE CONSTANTS!
- *
- * We spent *weeks* testing this code, making sure it is as perfect and
- * correct as possible. Are you going to do the same after making your
- * changes? Probably not. Besides, any change to these constants will break
- * the runtime tests, which are extremely important for your security.
- * You're literally millions of times more likely to screw up your own
- * security by changing something here than you are to fall victim to an
- * 128-bit key brute-force attack. You're also breaking your own
- * compatibility with future updates to this library, so you'll be left
- * vulnerable if we ever find a security bug and release a fix.
- *
- * So, PLEASE, do not change these constants.
- */
- const CIPHER = 'aes-128';
- const KEY_BYTE_SIZE = 16;
- const CIPHER_MODE = 'cbc';
- const HASH_FUNCTION = 'sha256';
- const MAC_BYTE_SIZE = 32;
- const ENCRYPTION_INFO = 'DefusePHP|KeyForEncryption';
- const AUTHENTICATION_INFO = 'DefusePHP|KeyForAuthentication';
-
- /*
- * Use this to generate a random encryption key.
- */
- public static function CreateNewRandomKey()
- {
- self::RuntimeTest();
- return self::SecureRandom(self::KEY_BYTE_SIZE);
- }
-
- /*
- * Encrypts a message.
- * $plaintext is the message to encrypt.
- * $key is the encryption key, a value generated by CreateNewRandomKey().
- * You MUST catch exceptions thrown by this function. See docs above.
- */
- public static function Encrypt($plaintext, $key)
- {
- self::RuntimeTest();
-
- if (self::our_strlen($key) !== self::KEY_BYTE_SIZE)
- {
- throw new CannotPerformOperationException("Bad key.");
- }
-
- $method = self::CIPHER.'-'.self::CIPHER_MODE;
-
- self::EnsureFunctionExists('openssl_get_cipher_methods');
- if (in_array($method, openssl_get_cipher_methods()) === FALSE) {
- throw new CannotPerformOperationException("Cipher method not supported.");
- }
-
- // Generate a sub-key for encryption.
- $keysize = self::KEY_BYTE_SIZE;
- $ekey = self::HKDF(self::HASH_FUNCTION, $key, $keysize, self::ENCRYPTION_INFO);
-
- // Generate a random initialization vector.
- self::EnsureFunctionExists("openssl_cipher_iv_length");
- $ivsize = openssl_cipher_iv_length($method);
- if ($ivsize === FALSE || $ivsize <= 0) {
- throw new CannotPerformOperationException();
- }
- $iv = self::SecureRandom($ivsize);
-
- $ciphertext = $iv . self::PlainEncrypt($plaintext, $ekey, $iv);
-
- // Generate a sub-key for authentication and apply the HMAC.
- $akey = self::HKDF(self::HASH_FUNCTION, $key, self::KEY_BYTE_SIZE, self::AUTHENTICATION_INFO);
- $auth = hash_hmac(self::HASH_FUNCTION, $ciphertext, $akey, true);
- $ciphertext = $auth . $ciphertext;
-
- return $ciphertext;
- }
-
- /*
- * Decrypts a ciphertext.
- * $ciphertext is the ciphertext to decrypt.
- * $key is the key that the ciphertext was encrypted with.
- * You MUST catch exceptions thrown by this function. See docs above.
- */
- public static function Decrypt($ciphertext, $key)
- {
- self::RuntimeTest();
-
- $method = self::CIPHER.'-'.self::CIPHER_MODE;
-
- self::EnsureFunctionExists('openssl_get_cipher_methods');
- if (in_array($method, openssl_get_cipher_methods()) === FALSE) {
- throw new CannotPerformOperationException("Cipher method not supported.");
- }
-
- // Extract the HMAC from the front of the ciphertext.
- if (self::our_strlen($ciphertext) <= self::MAC_BYTE_SIZE) {
- throw new InvalidCiphertextException();
- }
- $hmac = self::our_substr($ciphertext, 0, self::MAC_BYTE_SIZE);
- if ($hmac === FALSE) {
- throw new CannotPerformOperationException();
- }
- $ciphertext = self::our_substr($ciphertext, self::MAC_BYTE_SIZE);
- if ($ciphertext === FALSE) {
- throw new CannotPerformOperationException();
- }
-
- // Regenerate the same authentication sub-key.
- $akey = self::HKDF(self::HASH_FUNCTION, $key, self::KEY_BYTE_SIZE, self::AUTHENTICATION_INFO);
-
- if (self::VerifyHMAC($hmac, $ciphertext, $akey))
- {
- // Regenerate the same encryption sub-key.
- $keysize = self::KEY_BYTE_SIZE;
- $ekey = self::HKDF(self::HASH_FUNCTION, $key, $keysize, self::ENCRYPTION_INFO);
-
- // Extract the initialization vector from the ciphertext.
- self::EnsureFunctionExists("openssl_cipher_iv_length");
- $ivsize = openssl_cipher_iv_length($method);
- if ($ivsize === FALSE || $ivsize <= 0) {
- throw new CannotPerformOperationException();
- }
- if (self::our_strlen($ciphertext) <= $ivsize) {
- throw new InvalidCiphertextException();
- }
- $iv = self::our_substr($ciphertext, 0, $ivsize);
- if ($iv === FALSE) {
- throw new CannotPerformOperationException();
- }
- $ciphertext = self::our_substr($ciphertext, $ivsize);
- if ($ciphertext === FALSE) {
- throw new CannotPerformOperationException();
- }
-
- $plaintext = self::PlainDecrypt($ciphertext, $ekey, $iv);
-
- return $plaintext;
- }
- else
- {
- /*
- * We throw an exception instead of returning FALSE because we want
- * a script that doesn't handle this condition to CRASH, instead
- * of thinking the ciphertext decrypted to the value FALSE.
- */
- throw new InvalidCiphertextException();
- }
- }
-
- /*
- * Runs tests.
- * Raises CannotPerformOperationException or CryptoTestFailedException if
- * one of the tests fail. If any tests fails, your system is not capable of
- * performing encryption, so make sure you fail safe in that case.
- */
- public static function RuntimeTest()
- {
- // 0: Tests haven't been run yet.
- // 1: Tests have passed.
- // 2: Tests are running right now.
- // 3: Tests have failed.
- static $test_state = 0;
-
- if ($test_state === 1 || $test_state === 2) {
- return;
- }
-
- try {
- $test_state = 2;
- self::AESTestVector();
- self::HMACTestVector();
- self::HKDFTestVector();
-
- self::TestEncryptDecrypt();
- if (self::our_strlen(self::CreateNewRandomKey()) != self::KEY_BYTE_SIZE) {
- throw new CryptoTestFailedException();
- }
-
- if (self::ENCRYPTION_INFO == self::AUTHENTICATION_INFO) {
- throw new CryptoTestFailedException();
- }
- } catch (CryptoTestFailedException $ex) {
- // Do this, otherwise it will stay in the "tests are running" state.
- $test_state = 3;
- throw $ex;
- }
-
- // Change this to '0' make the tests always re-run (for benchmarking).
- $test_state = 1;
- }
-
- /*
- * Never call this method directly!
- */
- private static function PlainEncrypt($plaintext, $key, $iv)
- {
-
- $method = self::CIPHER.'-'.self::CIPHER_MODE;
-
- self::EnsureConstantExists("OPENSSL_RAW_DATA");
- self::EnsureFunctionExists("openssl_encrypt");
- $ciphertext = openssl_encrypt(
- $plaintext,
- $method,
- $key,
- OPENSSL_RAW_DATA,
- $iv
- );
-
- if ($ciphertext === false) {
- throw new CannotPerformOperationException();
- }
-
- return $ciphertext;
- }
-
- /*
- * Never call this method directly!
- */
- private static function PlainDecrypt($ciphertext, $key, $iv)
- {
-
- $method = self::CIPHER.'-'.self::CIPHER_MODE;
-
- self::EnsureConstantExists("OPENSSL_RAW_DATA");
- self::EnsureFunctionExists("openssl_encrypt");
- $plaintext = openssl_decrypt(
- $ciphertext,
- $method,
- $key,
- OPENSSL_RAW_DATA,
- $iv
- );
- if ($plaintext === FALSE) {
- throw new CannotPerformOperationException();
- }
-
- return $plaintext;
- }
-
- /*
- * Returns a random binary string of length $octets bytes.
- */
- private static function SecureRandom($octets)
- {
- self::EnsureFunctionExists("openssl_random_pseudo_bytes");
- $random = openssl_random_pseudo_bytes($octets, $crypto_strong);
- if ($crypto_strong === FALSE) {
- throw new CannotPerformOperationException();
- } else {
- return $random;
- }
- }
-
- /*
- * Use HKDF to derive multiple keys from one.
- * http://tools.ietf.org/html/rfc5869
- */
- private static function HKDF($hash, $ikm, $length, $info = '', $salt = NULL)
- {
- // Find the correct digest length as quickly as we can.
- $digest_length = self::MAC_BYTE_SIZE;
- if ($hash != self::HASH_FUNCTION) {
- $digest_length = self::our_strlen(hash_hmac($hash, '', '', true));
- }
-
- // Sanity-check the desired output length.
- if (empty($length) || !is_int($length) ||
- $length < 0 || $length > 255 * $digest_length) {
- throw new CannotPerformOperationException();
- }
-
- // "if [salt] not provided, is set to a string of HashLen zeroes."
- if (is_null($salt)) {
- $salt = str_repeat("\x00", $digest_length);
- }
-
- // HKDF-Extract:
- // PRK = HMAC-Hash(salt, IKM)
- // The salt is the HMAC key.
- $prk = hash_hmac($hash, $ikm, $salt, true);
-
- // HKDF-Expand:
-
- // This check is useless, but it serves as a reminder to the spec.
- if (self::our_strlen($prk) < $digest_length) {
- throw new CannotPerformOperationException();
- }
-
- // T(0) = ''
- $t = '';
- $last_block = '';
- for ($block_index = 1; self::our_strlen($t) < $length; $block_index++) {
- // T(i) = HMAC-Hash(PRK, T(i-1) | info | 0x??)
- $last_block = hash_hmac(
- $hash,
- $last_block . $info . chr($block_index),
- $prk,
- true
- );
- // T = T(1) | T(2) | T(3) | ... | T(N)
- $t .= $last_block;
- }
-
- // ORM = first L octets of T
- $orm = self::our_substr($t, 0, $length);
- if ($orm === FALSE) {
- throw new CannotPerformOperationException();
- }
- return $orm;
- }
-
- private static function VerifyHMAC($correct_hmac, $message, $key)
- {
- $message_hmac = hash_hmac(self::HASH_FUNCTION, $message, $key, true);
-
- // We can't just compare the strings with '==', since it would make
- // timing attacks possible. We could use the XOR-OR constant-time
- // comparison algorithm, but I'm not sure if that's good enough way up
- // here in an interpreted language. So we use the method of HMACing the
- // strings we want to compare with a random key, then comparing those.
-
- // NOTE: This leaks information when the strings are not the same
- // length, but they should always be the same length here. Enforce it:
- if (self::our_strlen($correct_hmac) !== self::our_strlen($message_hmac)) {
- throw new CannotPerformOperationException();
- }
-
- $blind = self::CreateNewRandomKey();
- $message_compare = hash_hmac(self::HASH_FUNCTION, $message_hmac, $blind);
- $correct_compare = hash_hmac(self::HASH_FUNCTION, $correct_hmac, $blind);
- return $correct_compare === $message_compare;
- }
-
- private static function TestEncryptDecrypt()
- {
- $key = self::CreateNewRandomKey();
- $data = "EnCrYpT EvErYThInG\x00\x00";
-
- // Make sure encrypting then decrypting doesn't change the message.
- $ciphertext = self::Encrypt($data, $key);
- try {
- $decrypted = self::Decrypt($ciphertext, $key);
- } catch (InvalidCiphertextException $ex) {
- // It's important to catch this and change it into a
- // CryptoTestFailedException, otherwise a test failure could trick
- // the user into thinking it's just an invalid ciphertext!
- throw new CryptoTestFailedException();
- }
- if($decrypted !== $data)
- {
- throw new CryptoTestFailedException();
- }
-
- // Modifying the ciphertext: Appending a string.
- try {
- self::Decrypt($ciphertext . "a", $key);
- throw new CryptoTestFailedException();
- } catch (InvalidCiphertextException $e) { /* expected */ }
-
- // Modifying the ciphertext: Changing an IV byte.
- try {
- $ciphertext[0] = chr((ord($ciphertext[0]) + 1) % 256);
- self::Decrypt($ciphertext, $key);
- throw new CryptoTestFailedException();
- } catch (InvalidCiphertextException $e) { /* expected */ }
-
- // Decrypting with the wrong key.
- $key = self::CreateNewRandomKey();
- $data = "abcdef";
- $ciphertext = self::Encrypt($data, $key);
- $wrong_key = self::CreateNewRandomKey();
- try {
- self::Decrypt($ciphertext, $wrong_key);
- throw new CryptoTestFailedException();
- } catch (InvalidCiphertextException $e) { /* expected */ }
-
- // Ciphertext too small (shorter than HMAC).
- $key = self::CreateNewRandomKey();
- $ciphertext = str_repeat("A", self::MAC_BYTE_SIZE - 1);
- try {
- self::Decrypt($ciphertext, $key);
- throw new CryptoTestFailedException();
- } catch (InvalidCiphertextException $e) { /* expected */ }
- }
-
- private static function HKDFTestVector()
- {
- // HKDF test vectors from RFC 5869
-
- // Test Case 1
- $ikm = str_repeat("\x0b", 22);
- $salt = self::hexToBytes("000102030405060708090a0b0c");
- $info = self::hexToBytes("f0f1f2f3f4f5f6f7f8f9");
- $length = 42;
- $okm = self::hexToBytes(
- "3cb25f25faacd57a90434f64d0362f2a" .
- "2d2d0a90cf1a5a4c5db02d56ecc4c5bf" .
- "34007208d5b887185865"
- );
- $computed_okm = self::HKDF("sha256", $ikm, $length, $info, $salt);
- if ($computed_okm !== $okm) {
- throw new CryptoTestFailedException();
- }
-
- // Test Case 7
- $ikm = str_repeat("\x0c", 22);
- $length = 42;
- $okm = self::hexToBytes(
- "2c91117204d745f3500d636a62f64f0a" .
- "b3bae548aa53d423b0d1f27ebba6f5e5" .
- "673a081d70cce7acfc48"
- );
- $computed_okm = self::HKDF("sha1", $ikm, $length);
- if ($computed_okm !== $okm) {
- throw new CryptoTestFailedException();
- }
-
- }
-
- private static function HMACTestVector()
- {
- // HMAC test vector From RFC 4231 (Test Case 1)
- $key = str_repeat("\x0b", 20);
- $data = "Hi There";
- $correct = "b0344c61d8db38535ca8afceaf0bf12b881dc200c9833da726e9376c2e32cff7";
- if (hash_hmac(self::HASH_FUNCTION, $data, $key) != $correct) {
- throw new CryptoTestFailedException();
- }
- }
-
- private static function AESTestVector()
- {
- // AES CBC mode test vector from NIST SP 800-38A
- $key = self::hexToBytes("2b7e151628aed2a6abf7158809cf4f3c");
- $iv = self::hexToBytes("000102030405060708090a0b0c0d0e0f");
- $plaintext = self::hexToBytes(
- "6bc1bee22e409f96e93d7e117393172a" .
- "ae2d8a571e03ac9c9eb76fac45af8e51" .
- "30c81c46a35ce411e5fbc1191a0a52ef" .
- "f69f2445df4f9b17ad2b417be66c3710"
- );
- $ciphertext = self::hexToBytes(
- "7649abac8119b246cee98e9b12e9197d" .
- "5086cb9b507219ee95db113a917678b2" .
- "73bed6b8e3c1743b7116e69e22229516" .
- "3ff1caa1681fac09120eca307586e1a7" .
- /* Block due to padding. Not from NIST test vector.
- Padding Block: 10101010101010101010101010101010
- Ciphertext: 3ff1caa1681fac09120eca307586e1a7
- (+) 2fe1dab1780fbc19021eda206596f1b7
- AES 8cb82807230e1321d3fae00d18cc2012
-
- */
- "8cb82807230e1321d3fae00d18cc2012"
- );
-
- $computed_ciphertext = self::PlainEncrypt($plaintext, $key, $iv);
- if ($computed_ciphertext !== $ciphertext) {
- throw new CryptoTestFailedException();
- }
-
- $computed_plaintext = self::PlainDecrypt($ciphertext, $key, $iv);
- if ($computed_plaintext !== $plaintext) {
- throw new CryptoTestFailedException();
- }
- }
-
- /* WARNING: Do not call this function on secrets. It creates side channels. */
- private static function hexToBytes($hex_string)
- {
- return pack("H*", $hex_string);
- }
-
- private static function EnsureConstantExists($name)
- {
- if (!defined($name)) {
- throw new CannotPerformOperationException();
- }
- }
-
- private static function EnsureFunctionExists($name)
- {
- if (!function_exists($name)) {
- throw new CannotPerformOperationException();
- }
- }
-
- /*
- * We need these strlen() and substr() functions because when
- * 'mbstring.func_overload' is set in php.ini, the standard strlen() and
- * substr() are replaced by mb_strlen() and mb_substr().
- */
-
- private static function our_strlen($str)
- {
- if (function_exists('mb_strlen')) {
- $length = mb_strlen($str, '8bit');
- if ($length === FALSE) {
- throw new CannotPerformOperationException();
- }
- return $length;
- } else {
- return strlen($str);
- }
- }
-
- private static function our_substr($str, $start, $length = NULL)
- {
- if (function_exists('mb_substr'))
- {
- // mb_substr($str, 0, NULL, '8bit') returns an empty string on PHP
- // 5.3, so we have to find the length ourselves.
- if (!isset($length)) {
- if ($start >= 0) {
- $length = self::our_strlen($str) - $start;
- } else {
- $length = -$start;
- }
- }
-
- return mb_substr($str, $start, $length, '8bit');
- }
-
- // Unlike mb_substr(), substr() doesn't accept NULL for length
- if (isset($length)) {
- return substr($str, $start, $length);
- } else {
- return substr($str, $start);
- }
- }
-
-}
-
-/*
- * We want to catch all uncaught exceptions that come from the Crypto class,
- * since by default, PHP will leak the key in the stack trace from an uncaught
- * exception. This is a really ugly hack, but I think it's justified.
- *
- * Everything up to handler() getting called should be reliable, so this should
- * reliably suppress the stack traces. The rest is just a bonus so that we don't
- * make it impossible to debug other exceptions.
- *
- * This bit of code was adapted from: http://stackoverflow.com/a/7939492
- */
-
-class CryptoExceptionHandler
-{
- private $rethrow = NULL;
-
- public function __construct()
- {
- set_exception_handler(array($this, "handler"));
- }
-
- public function handler($ex)
- {
- if (
- $ex instanceof InvalidCiphertextException ||
- $ex instanceof CannotPerformOperationException ||
- $ex instanceof CryptoTestFailedException
- ) {
- echo "FATAL ERROR: Uncaught crypto exception. Suppresssing output.\n";
- } else {
- /* Re-throw the exception in the destructor. */
- $this->rethrow = $ex;
- }
- }
-
- public function __destruct() {
- if ($this->rethrow) {
- throw $this->rethrow;
- }
- }
-}
-
-$crypto_exception_handler_object_dont_touch_me = new CryptoExceptionHandler();
-
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