I am doing encryption which is working good but with same method I am doing decryption I am getting blank string not getting decryption string. I am using method AES-256-ECB and key is hexadecimal so I pass as
$key = pack('H*','xxxxxxxxxxxx');
Encryption is going correct but decryption is not working. Please help me what I am doing wrong.
function encrypt(string $data, string $key, string $method): string
{
$ivSize = openssl_cipher_iv_length($method);
$iv = openssl_random_pseudo_bytes($ivSize);
$encrypted = openssl_encrypt($data, $method, $key, OPENSSL_RAW_DATA, $iv);
$encrypted = strtoupper(implode(null, unpack('H*', $encrypted)));
return $encrypted;
}
function decrypt(string $data, string $key, string $method): string
{
$data = pack('H*', $data);
$ivSize = openssl_cipher_iv_length($method);
$iv = $iv = openssl_random_pseudo_bytes($ivSize);
$decrypted = openssl_decrypt($data, $method, $key, OPENSSL_RAW_DATA, $iv);
return trim($decrypted);
}
Your functions are working perfectly for me with the following code:
$key = pack('H*','aaaaaaaaaaaaa');
$method = 'aes-256-ecb';
$encrypted = encrypt('test string', $key, $method);
$decrypted = decrypt($encrypted, $key.'a', $method);
echo $decrypted; // Output: 'test string'
Since you're getting an empty string for decryption, this means that you've either got the wrong key or cipher text when decrypting. Make sure the key you are using for decryption is exactly the same as the key you're using for encryption, including any manipulations done on it, such as the pack() function you've done here. Even one byte difference and you're not going to be able to decrypt.
Also make sure neither the key nor the cipher text are being truncated when they are stored. If using a database and the column type is too small for what you are trying to store, it will truncate the values.
The mcrypt-extension is deprecated will be removed in PHP 7.2 according to the comment posted here. So I am looking for an alternative way to encrypt passwords.
Right now I am using something like
mcrypt_encrypt(MCRYPT_RIJNDAEL_128, md5($key, true), $string, MCRYPT_MODE_CBC, $iv)
I need your opinion for the best/strongest way to encrypt passwords, the encrypted password should of course supported by PHP 7.xx and should also be decryptable because my customers do want to have an option to 'recover' their passwords without generating a new one.
It's best practice to hash passwords so they are not decryptable. This makes things slightly more difficult for attackers that may have gained access to your database or files.
If you must encrypt your data and have it decryptable, a guide to secure encryption/decryption is available at https://paragonie.com/white-paper/2015-secure-php-data-encryption. To summarize that link:
Use Libsodium - A PHP extension
If you can't use Libsodium, use defuse/php-encryption - Straight PHP code
If you can't use Libsodium or defuse/php-encryption, use OpenSSL - A lot of servers will already have this installed. If not, it can be compiled with --with-openssl[=DIR]
As suggested by #rqLizard, you can use openssl_encrypt/openssl_decrypt PHP functions instead which provides a much
better alternative to implement AES (The Advanced Encryption Standard) also known as Rijndael encryption.
As per the following Scott's comment at php.net:
If you're writing code to encrypt/encrypt data in 2015, you should use openssl_encrypt() and openssl_decrypt(). The underlying library (libmcrypt) has been abandoned since 2007, and performs far worse than OpenSSL (which leverages AES-NI on modern processors and is cache-timing safe).
Also, MCRYPT_RIJNDAEL_256 is not AES-256, it's a different variant of the Rijndael block cipher. If you want AES-256 in mcrypt, you have to use MCRYPT_RIJNDAEL_128 with a 32-byte key. OpenSSL makes it more obvious which mode you are using (i.e. aes-128-cbc vs aes-256-ctr).
OpenSSL also uses PKCS7 padding with CBC mode rather than mcrypt's NULL byte padding. Thus, mcrypt is more likely to make your code vulnerable to padding oracle attacks than OpenSSL.
Finally, if you are not authenticating your ciphertexts (Encrypt Then MAC), you're doing it wrong.
Further reading:
Using Encryption and Authentication Correctly (for PHP developers).
If You're Typing the Word MCRYPT Into Your PHP Code, You're Doing It Wrong.
Code examples
Example #1
AES Authenticated Encryption in GCM mode example for PHP 7.1+
<?php
//$key should have been previously generated in a cryptographically safe way, like openssl_random_pseudo_bytes
$plaintext = "message to be encrypted";
$cipher = "aes-128-gcm";
if (in_array($cipher, openssl_get_cipher_methods()))
{
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext = openssl_encrypt($plaintext, $cipher, $key, $options=0, $iv, $tag);
//store $cipher, $iv, and $tag for decryption later
$original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, $options=0, $iv, $tag);
echo $original_plaintext."\n";
}
?>
Example #2
AES Authenticated Encryption example for PHP 5.6+
<?php
//$key previously generated safely, ie: openssl_random_pseudo_bytes
$plaintext = "message to be encrypted";
$ivlen = openssl_cipher_iv_length($cipher="AES-128-CBC");
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext_raw = openssl_encrypt($plaintext, $cipher, $key, $options=OPENSSL_RAW_DATA, $iv);
$hmac = hash_hmac('sha256', $ciphertext_raw, $key, $as_binary=true);
$ciphertext = base64_encode( $iv.$hmac.$ciphertext_raw );
//decrypt later....
$c = base64_decode($ciphertext);
$ivlen = openssl_cipher_iv_length($cipher="AES-128-CBC");
$iv = substr($c, 0, $ivlen);
$hmac = substr($c, $ivlen, $sha2len=32);
$ciphertext_raw = substr($c, $ivlen+$sha2len);
$original_plaintext = openssl_decrypt($ciphertext_raw, $cipher, $key, $options=OPENSSL_RAW_DATA, $iv);
$calcmac = hash_hmac('sha256', $ciphertext_raw, $key, $as_binary=true);
if (hash_equals($hmac, $calcmac))//PHP 5.6+ timing attack safe comparison
{
echo $original_plaintext."\n";
}
?>
Example #3
Based on above examples, I've changed the following code which aims at encrypting user's session id:
class Session {
/**
* Encrypts the session ID and returns it as a base 64 encoded string.
*
* #param $session_id
* #return string
*/
public function encrypt($session_id) {
// Get the MD5 hash salt as a key.
$key = $this->_getSalt();
// For an easy iv, MD5 the salt again.
$iv = $this->_getIv();
// Encrypt the session ID.
$encrypt = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $session_id, MCRYPT_MODE_CBC, $iv);
// Base 64 encode the encrypted session ID.
$encryptedSessionId = base64_encode($encrypt);
// Return it.
return $encryptedSessionId;
}
/**
* Decrypts a base 64 encoded encrypted session ID back to its original form.
*
* #param $encryptedSessionId
* #return string
*/
public function decrypt($encryptedSessionId) {
// Get the MD5 hash salt as a key.
$key = $this->_getSalt();
// For an easy iv, MD5 the salt again.
$iv = $this->_getIv();
// Decode the encrypted session ID from base 64.
$decoded = base64_decode($encryptedSessionId);
// Decrypt the string.
$decryptedSessionId = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $decoded, MCRYPT_MODE_CBC, $iv);
// Trim the whitespace from the end.
$session_id = rtrim($decryptedSessionId, "\0");
// Return it.
return $session_id;
}
public function _getIv() {
return md5($this->_getSalt());
}
public function _getSalt() {
return md5($this->drupal->drupalGetHashSalt());
}
}
into:
class Session {
const SESS_CIPHER = 'aes-128-cbc';
/**
* Encrypts the session ID and returns it as a base 64 encoded string.
*
* #param $session_id
* #return string
*/
public function encrypt($session_id) {
// Get the MD5 hash salt as a key.
$key = $this->_getSalt();
// For an easy iv, MD5 the salt again.
$iv = $this->_getIv();
// Encrypt the session ID.
$ciphertext = openssl_encrypt($session_id, self::SESS_CIPHER, $key, $options=OPENSSL_RAW_DATA, $iv);
// Base 64 encode the encrypted session ID.
$encryptedSessionId = base64_encode($ciphertext);
// Return it.
return $encryptedSessionId;
}
/**
* Decrypts a base 64 encoded encrypted session ID back to its original form.
*
* #param $encryptedSessionId
* #return string
*/
public function decrypt($encryptedSessionId) {
// Get the Drupal hash salt as a key.
$key = $this->_getSalt();
// Get the iv.
$iv = $this->_getIv();
// Decode the encrypted session ID from base 64.
$decoded = base64_decode($encryptedSessionId, TRUE);
// Decrypt the string.
$decryptedSessionId = openssl_decrypt($decoded, self::SESS_CIPHER, $key, $options=OPENSSL_RAW_DATA, $iv);
// Trim the whitespace from the end.
$session_id = rtrim($decryptedSessionId, '\0');
// Return it.
return $session_id;
}
public function _getIv() {
$ivlen = openssl_cipher_iv_length(self::SESS_CIPHER);
return substr(md5($this->_getSalt()), 0, $ivlen);
}
public function _getSalt() {
return $this->drupal->drupalGetHashSalt();
}
}
To clarify, above change is not a true conversion since the two encryption uses a different block size and a different encrypted data. Additionally, the default padding is different, MCRYPT_RIJNDAEL only supports non-standard null padding. #zaph
Additional notes (from the #zaph's comments):
Rijndael 128 (MCRYPT_RIJNDAEL_128) is equivalent to AES, however Rijndael 256 (MCRYPT_RIJNDAEL_256) is not AES-256 as the 256 specifies a block size of 256-bits, whereas AES has only one block size: 128-bits. So basically Rijndael with a block size of 256-bits (MCRYPT_RIJNDAEL_256) has been mistakenly named due to the choices by the mcrypt developers. #zaph
Rijndael with a block size of 256 may be less secure than with a block size of 128-bits because the latter has had much more reviews and uses. Secondly, interoperability is hindered in that while AES is generally available, where Rijndael with a block size of 256-bits is not.
Encryption with different block sizes for Rijndael produces different encrypted data.
For example, MCRYPT_RIJNDAEL_256 (not equivalent to AES-256) defines a different variant of the Rijndael block cipher with size of 256-bits and a key size based on the passed in key, where aes-256-cbc is Rijndael with a block size of 128-bits with a key size of 256-bits. Therefore they're using different block sizes which produces entirely different encrypted data as mcrypt uses the number to specify the block size, where OpenSSL used the number to specify the key size (AES only has one block size of 128-bits). So basically AES is Rijndael with a block size of 128-bits and key sizes of 128, 192 and 256 bits. Therefore it's better to use AES, which is called Rijndael 128 in OpenSSL.
As detailed by other answers here, the best solution I found is using OpenSSL. It is built into PHP and you don't need any external library. Here are simple examples:
To encrypt:
function encrypt($key, $payload) {
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length('aes-256-cbc'));
$encrypted = openssl_encrypt($payload, 'aes-256-cbc', $key, 0, $iv);
return base64_encode($encrypted . '::' . $iv);
}
To decrypt:
function decrypt($key, $garble) {
list($encrypted_data, $iv) = explode('::', base64_decode($garble), 2);
return openssl_decrypt($encrypted_data, 'aes-256-cbc', $key, 0, $iv);
}
Reference link: https://www.shift8web.ca/2017/04/how-to-encrypt-and-execute-your-php-code-with-mcrypt/
Pure-PHP implementation of Rijndael exists with phpseclib available as composer package and works on PHP 7.3 (tested by me).
There's a page on the phpseclib docs, which generates sample code after you input the basic variables (cipher, mode, key size, bit size). It outputs the following for Rijndael, ECB, 256, 256:
a code with mycrypt
$decoded = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, ENCRYPT_KEY, $term, MCRYPT_MODE_ECB);
works like this with the library
$rijndael = new \phpseclib\Crypt\Rijndael(\phpseclib\Crypt\Rijndael::MODE_ECB);
$rijndael->setKey(ENCRYPT_KEY);
$rijndael->setKeyLength(256);
$rijndael->disablePadding();
$rijndael->setBlockLength(256);
$decoded = $rijndael->decrypt($term);
* $term was base64_decoded
You can use phpseclib pollyfill package. You can not use open ssl or libsodium for encrypt/decrypt with rijndael 256.
Another issue, you don't need replacement any code.
You should use OpenSSL over mcrypt as it's actively developed and maintained. It provides better security, maintainability and portability. Secondly it performs AES encryption/decryption much faster. It uses PKCS7 padding by default, but you can specify OPENSSL_ZERO_PADDING if you need it. To use with a 32-byte binary key, you can specify aes-256-cbc which is much obvious than MCRYPT_RIJNDAEL_128.
Here is the code example using Mcrypt:
Unauthenticated AES-256-CBC encryption library written in Mcrypt with PKCS7 padding.
/**
* This library is unsafe because it does not MAC after encrypting
*/
class UnsafeMcryptAES
{
const CIPHER = MCRYPT_RIJNDAEL_128;
public static function encrypt($message, $key)
{
if (mb_strlen($key, '8bit') !== 32) {
throw new Exception("Needs a 256-bit key!");
}
$ivsize = mcrypt_get_iv_size(self::CIPHER);
$iv = mcrypt_create_iv($ivsize, MCRYPT_DEV_URANDOM);
// Add PKCS7 Padding
$block = mcrypt_get_block_size(self::CIPHER);
$pad = $block - (mb_strlen($message, '8bit') % $block, '8bit');
$message .= str_repeat(chr($pad), $pad);
$ciphertext = mcrypt_encrypt(
MCRYPT_RIJNDAEL_128,
$key,
$message,
MCRYPT_MODE_CBC,
$iv
);
return $iv . $ciphertext;
}
public static function decrypt($message, $key)
{
if (mb_strlen($key, '8bit') !== 32) {
throw new Exception("Needs a 256-bit key!");
}
$ivsize = mcrypt_get_iv_size(self::CIPHER);
$iv = mb_substr($message, 0, $ivsize, '8bit');
$ciphertext = mb_substr($message, $ivsize, null, '8bit');
$plaintext = mcrypt_decrypt(
MCRYPT_RIJNDAEL_128,
$key,
$ciphertext,
MCRYPT_MODE_CBC,
$iv
);
$len = mb_strlen($plaintext, '8bit');
$pad = ord($plaintext[$len - 1]);
if ($pad <= 0 || $pad > $block) {
// Padding error!
return false;
}
return mb_substr($plaintext, 0, $len - $pad, '8bit');
}
}
And here is the version written using OpenSSL:
/**
* This library is unsafe because it does not MAC after encrypting
*/
class UnsafeOpensslAES
{
const METHOD = 'aes-256-cbc';
public static function encrypt($message, $key)
{
if (mb_strlen($key, '8bit') !== 32) {
throw new Exception("Needs a 256-bit key!");
}
$ivsize = openssl_cipher_iv_length(self::METHOD);
$iv = openssl_random_pseudo_bytes($ivsize);
$ciphertext = openssl_encrypt(
$message,
self::METHOD,
$key,
OPENSSL_RAW_DATA,
$iv
);
return $iv . $ciphertext;
}
public static function decrypt($message, $key)
{
if (mb_strlen($key, '8bit') !== 32) {
throw new Exception("Needs a 256-bit key!");
}
$ivsize = openssl_cipher_iv_length(self::METHOD);
$iv = mb_substr($message, 0, $ivsize, '8bit');
$ciphertext = mb_substr($message, $ivsize, null, '8bit');
return openssl_decrypt(
$ciphertext,
self::METHOD,
$key,
OPENSSL_RAW_DATA,
$iv
);
}
}
Source: If You're Typing the Word MCRYPT Into Your PHP Code, You're Doing It Wrong.
I am using this on PHP 7.2.x, it's working fine for me:
public function make_hash($userStr){
try{
/**
* Used and tested on PHP 7.2x, Salt has been removed manually, it is now added by PHP
*/
return password_hash($userStr, PASSWORD_BCRYPT);
}catch(Exception $exc){
$this->tempVar = $exc->getMessage();
return false;
}
}
and then authenticate the hash with the following function:
public function varify_user($userStr,$hash){
try{
if (password_verify($userStr, $hash)) {
return true;
}
else {
return false;
}
}catch(Exception $exc){
$this->tempVar = $exc->getMessage();
return false;
}
}
Example:
//create hash from user string
$user_password = $obj->make_hash2($user_key);
and to authenticate this hash use the following code:
if($obj->varify_user($key, $user_key)){
//this is correct, you can proceed with
}
That's all.
As pointed out, you should not be storing your users' passwords in a format that is decryptable. Reversable encryption provides an easy route for hackers to find out your users' passwords, which extends to putting your users' accounts at other sites at risk should they use the same password there.
PHP provides a pair of powerful functions for random-salted, one-way hash encryption — password_hash() and password_verify(). Because the hash is automatically random-salted, there is no way for hackers to utilize precompiled tables of password hashes to reverse-engineer the password. Set the PASSWORD_DEFAULT option and future versions of PHP will automatically use stronger algorithms to generate password hashes without you having to update your code.
I was able to translate my Crypto object
Get a copy of php with mcrypt to decrypt the old data. I went to http://php.net/get/php-7.1.12.tar.gz/from/a/mirror, compiled it, then added the ext/mcrypt extension (configure;make;make install). I think I had to add the extenstion=mcrypt.so line to the php.ini as well. A series of scripts to build intermediate versions of the data with all data unencrypted.
Build a public and private key for openssl
openssl genrsa -des3 -out pkey.pem 2048
(set a password)
openssl rsa -in pkey.pem -out pkey-pub.pem -outform PEM -pubout
To Encrypt (using public key) use openssl_seal. From what I've read, openssl_encrypt using an RSA key is limited to 11 bytes less than the key length (See http://php.net/manual/en/function.openssl-public-encrypt.php comment by Thomas Horsten)
$pubKey = openssl_get_publickey(file_get_contents('./pkey-pub.pem'));
openssl_seal($pwd, $sealed, $ekeys, [ $pubKey ]);
$encryptedPassword = base64_encode($sealed);
$key = base64_encode($ekeys[0]);
You could probably store the raw binary.
To Decrypt (using private key)
$passphrase="passphrase here";
$privKey = openssl_get_privatekey(file_get_contents('./pkey.pem'), $passphrase);
// I base64_decode() from my db columns
openssl_open($encryptedPassword, $plain, $key, $privKey);
echo "<h3>Password=$plain</h3>";
P.S. You can't encrypt the empty string ("")
P.P.S. This is for a password database not for user validation.
You should use openssl_encrypt() function.
I want to decrypt an encrypted response using mcrypt_decrypt but this doesn't work, so I'm using this snippet of code for test and the response should be "This is a test":
// Encryption Algorithm
// the $shared_key and $init_vector are not real
$cipher_alg = MCRYPT_RIJNDAEL_128;
$shared_key = "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF";
$key = pack("H*", $shared_key);
$init_vector = "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF";
$iv = pack("H*", $init_vector);
echo mcrypt_decrypt($cipher_alg, $key, utf8_encode(mcrypt_encrypt(
$cipher_alg, $key, utf8_encode('This is a test'), MCRYPT_MODE_CBC, $iv)), MCRYPT_MODE_CBC, $iv);
And the response is:
æ †,?7÷q†Ý³‚¢gTô1ò‚ù’Ü”®mÀ{ëQS
What I'm doing wrong?
You are utf8 encoding the encrypted stuff. That way it is modified and can not be decrypted anymore.
echo mcrypt_decrypt($cipher_alg, $key, mcrypt_encrypt(
$cipher_alg, $key, 'This is a test'), MCRYPT_MODE_CBC, $iv), MCRYPT_MODE_CBC, $iv);
I am working on some PHP code to perform AES string encryption and decryption. The encryption is working fine but I can't seem to decrypt it.
Below is the code that does the encryption and adds the required padding.
function encrypt($data)
{
$iv = "PRIVATE";
$key = CIPHERKEY;
return base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, addpadding($data), MCRYPT_MODE_CBC, $iv));
}
function addpadding($string, $blocksize = 16)
{
$len = strlen($string);
$pad = $blocksize - ($len % $blocksize);
$string .= str_repeat(chr($pad), $pad);
return $string;
}
The code above is working fine the code below where it does the decryption keeps on failing. I try and do the decryption and then strip the padding but false is always returned from the padding function.
Below is the code that does the decryption and the stripping.
function strippadding($string)
{
$slast = ord(substr($string, -1));
$slastc = chr($slast);
$pcheck = substr($string, -$slast);
if(preg_match("/$slastc{".$slast."}/", $string)){
$string = substr($string, 0, strlen($string)-$slast);
return $string;
} else {
return "false";
}
}
function decrypt($data)
{
$iv = "PRIVATE";
$key = CIPHERKEY;
//$decoded = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
$decrytped = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $data, MCRYPT_MODE_CBC, $iv);
$base64Decoded = base64_decode($decrytped);
return strippadding($base64Decoded);
}
Thanks for any help you can provide.
In your decryption method, the decrypt and base64 steps are backwards. It's important that in whatever order you do your operations for encrypting, you do the reverse to decrypt.
In your encrypt method, you're base64 encoding the ciphertext:
base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, addpadding($data), MCRYPT_MODE_CBC, $iv));
When you decrypt, you need to undo the base64 encoding, and then decrypt that result.
$base64Decoded = base64_decode($data);
$decrytped = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $base64Decoded, MCRYPT_MODE_CBC, $iv);
Also, it looks like mcrypt will handle padding uneven blocks, so your addpadding() method might be superfluous.
You are using a too-short IV which is less than the blocksize. I assume this results in using a different IV on decryption. Blocksize is 16 bytes, so the IV should be 16 bytes, but your fixed-string IV is only 7 bytes (8 if you count the terminating zero byte which the underlying C code probably adds).
Instead of using a fixed string, you should be using a random IV generated by mcrypt_create_iv(). You can find out the length of one block by using mcrypt_get_iv_size() as shown in Example 1 in the mcrypt_create_iv() PHP manual. You would then send/store the random IV prepended to the ciphertext so you know what the IV was on decryption.
Also, mcrypt does its own padding, so you don't need to. And, as mfanto pointed out, you need to decode Base64 before decryption, not after.