Related
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.
What I mean is:
Original String + Salt or Key --> Encrypted String
Encrypted String + Salt or Key --> Decrypted (Original String)
Maybe something like:
"hello world!" + "ABCD1234" --> Encrypt --> "2a2ffa8f13220befbe30819047e23b2c" (may be, for e.g)
"2a2ffa8f13220befbe30819047e23b2c" --> Decrypt with "ABCD1234" --> "hello world!"
In PHP, how can you do this?
Attempted to use Crypt_Blowfish, but it didn't work for me.
Before you do anything further, seek to understand the difference between encryption and authentication, and why you probably want authenticated encryption rather than just encryption.
To implement authenticated encryption, you want to Encrypt then MAC. The order of encryption and authentication is very important! One of the existing answers to this question made this mistake; as do many cryptography libraries written in PHP.
You should avoid implementing your own cryptography, and instead use a secure library written by and reviewed by cryptography experts.
Update: PHP 7.2 now provides libsodium! For best security, update your systems to use PHP 7.2 or higher and only follow the libsodium advice in this answer.
Use libsodium if you have PECL access (or sodium_compat if you want libsodium without PECL); otherwise...
Use defuse/php-encryption; don't roll your own cryptography!
Both of the libraries linked above make it easy and painless to implement authenticated encryption into your own libraries.
If you still want to write and deploy your own cryptography library, against the conventional wisdom of every cryptography expert on the Internet, these are the steps you would have to take.
Encryption:
Encrypt using AES in CTR mode. You may also use GCM (which removes the need for a separate MAC). Additionally, ChaCha20 and Salsa20 (provided by libsodium) are stream ciphers and do not need special modes.
Unless you chose GCM above, you should authenticate the ciphertext with HMAC-SHA-256 (or, for the stream ciphers, Poly1305 -- most libsodium APIs do this for you). The MAC should cover the IV as well as the ciphertext!
Decryption:
Unless Poly1305 or GCM is used, recalculate the MAC of the ciphertext and compare it with the MAC that was sent using hash_equals(). If it fails, abort.
Decrypt the message.
Other Design Considerations:
Do not compress anything ever. Ciphertext is not compressible; compressing plaintext before encryption can lead to information leaks (e.g. CRIME and BREACH on TLS).
Make sure you use mb_strlen() and mb_substr(), using the '8bit' character set mode to prevent mbstring.func_overload issues.
IVs should be generating using a CSPRNG; If you're using mcrypt_create_iv(), DO NOT USE MCRYPT_RAND!
Also check out random_compat.
Unless you're using an AEAD construct, ALWAYS encrypt then MAC!
bin2hex(), base64_encode(), etc. may leak information about your encryption keys via cache timing. Avoid them if possible.
Even if you follow the advice given here, a lot can go wrong with cryptography. Always have a cryptography expert review your implementation. If you are not fortunate enough to be personal friends with a cryptography student at your local university, you can always try the Cryptography Stack Exchange forum for advice.
If you need a professional analysis of your implementation, you can always hire a reputable team of security consultants to review your PHP cryptography code (disclosure: my employer).
Important: When to Not Use Encryption
Don't encrypt passwords. You want to hash them instead, using one of these password-hashing algorithms:
Argon2
scrypt
bcrypt
PBKDF2-SHA256 with 86,000 iterations
Never use a general-purpose hash function (MD5, SHA256) for password storage.
Don't encrypt URL Parameters. It's the wrong tool for the job.
PHP String Encryption Example with Libsodium
If you are on PHP < 7.2 or otherwise do not have libsodium installed, you can use sodium_compat to accomplish the same result (albeit slower).
<?php
declare(strict_types=1);
/**
* Encrypt a message
*
* #param string $message - message to encrypt
* #param string $key - encryption key
* #return string
* #throws RangeException
*/
function safeEncrypt(string $message, string $key): string
{
if (mb_strlen($key, '8bit') !== SODIUM_CRYPTO_SECRETBOX_KEYBYTES) {
throw new RangeException('Key is not the correct size (must be 32 bytes).');
}
$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
$cipher = base64_encode(
$nonce.
sodium_crypto_secretbox(
$message,
$nonce,
$key
)
);
sodium_memzero($message);
sodium_memzero($key);
return $cipher;
}
/**
* Decrypt a message
*
* #param string $encrypted - message encrypted with safeEncrypt()
* #param string $key - encryption key
* #return string
* #throws Exception
*/
function safeDecrypt(string $encrypted, string $key): string
{
$decoded = base64_decode($encrypted);
$nonce = mb_substr($decoded, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, '8bit');
$ciphertext = mb_substr($decoded, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, null, '8bit');
$plain = sodium_crypto_secretbox_open(
$ciphertext,
$nonce,
$key
);
if (!is_string($plain)) {
throw new Exception('Invalid MAC');
}
sodium_memzero($ciphertext);
sodium_memzero($key);
return $plain;
}
Then to test it out:
<?php
// This refers to the previous code block.
require "safeCrypto.php";
// Do this once then store it somehow:
$key = random_bytes(SODIUM_CRYPTO_SECRETBOX_KEYBYTES);
$message = 'We are all living in a yellow submarine';
$ciphertext = safeEncrypt($message, $key);
$plaintext = safeDecrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
Halite - Libsodium Made Easier
One of the projects I've been working on is an encryption library called Halite, which aims to make libsodium easier and more intuitive.
<?php
use \ParagonIE\Halite\KeyFactory;
use \ParagonIE\Halite\Symmetric\Crypto as SymmetricCrypto;
// Generate a new random symmetric-key encryption key. You're going to want to store this:
$key = new KeyFactory::generateEncryptionKey();
// To save your encryption key:
KeyFactory::save($key, '/path/to/secret.key');
// To load it again:
$loadedkey = KeyFactory::loadEncryptionKey('/path/to/secret.key');
$message = 'We are all living in a yellow submarine';
$ciphertext = SymmetricCrypto::encrypt($message, $key);
$plaintext = SymmetricCrypto::decrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
All of the underlying cryptography is handled by libsodium.
Example with defuse/php-encryption
<?php
/**
* This requires https://github.com/defuse/php-encryption
* php composer.phar require defuse/php-encryption
*/
use Defuse\Crypto\Crypto;
use Defuse\Crypto\Key;
require "vendor/autoload.php";
// Do this once then store it somehow:
$key = Key::createNewRandomKey();
$message = 'We are all living in a yellow submarine';
$ciphertext = Crypto::encrypt($message, $key);
$plaintext = Crypto::decrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
Note: Crypto::encrypt() returns hex-encoded output.
Encryption Key Management
If you're tempted to use a "password", stop right now. You need a random 128-bit encryption key, not a human memorable password.
You can store an encryption key for long-term use like so:
$storeMe = bin2hex($key);
And, on demand, you can retrieve it like so:
$key = hex2bin($storeMe);
I strongly recommend just storing a randomly generated key for long-term use instead of any sort of password as the key (or to derive the key).
If you're using Defuse's library:
$string = $keyObject->saveToAsciiSafeString()
$loaded = Key::loadFromAsciiSafeString($string);
"But I really want to use a password."
That's a bad idea, but okay, here's how to do it safely.
First, generate a random key and store it in a constant.
/**
* Replace this with your own salt!
* Use bin2hex() then add \x before every 2 hex characters, like so:
*/
define('MY_PBKDF2_SALT', "\x2d\xb7\x68\x1a\x28\x15\xbe\x06\x33\xa0\x7e\x0e\x8f\x79\xd5\xdf");
Note that you're adding extra work and could just use this constant as the key and save yourself a lot of heartache!
Then use PBKDF2 (like so) to derive a suitable encryption key from your password rather than encrypting with your password directly.
/**
* Get an AES key from a static password and a secret salt
*
* #param string $password Your weak password here
* #param int $keysize Number of bytes in encryption key
*/
function getKeyFromPassword($password, $keysize = 16)
{
return hash_pbkdf2(
'sha256',
$password,
MY_PBKDF2_SALT,
100000, // Number of iterations
$keysize,
true
);
}
Don't just use a 16-character password. Your encryption key will be comically broken.
I'm late to the party, but searching for the correct way to do it I came across this page it was one of the top Google search returns, so I will like to share my view on the problem, which I consider it to be up to date at the time of writing this post (beginning of 2017). From PHP 7.1.0 the mcrypt_decrypt and mcrypt_encrypt is going to be deprecated, so building future proof code should use openssl_encrypt and openssl_decrypt
You can do something like:
$string_to_encrypt="Test";
$password="password";
$encrypted_string=openssl_encrypt($string_to_encrypt,"AES-128-ECB",$password);
$decrypted_string=openssl_decrypt($encrypted_string,"AES-128-ECB",$password);
Important: This uses ECB mode, which isn't secure. If you want a simple solution without taking a crash course in cryptography engineering, don't write it yourself, just use a library.
You can use any other chipper methods as well, depending on your security need. To find out the available chipper methods please see the openssl_get_cipher_methods function.
What not to do
WARNING:
This answer uses ECB. ECB is not an encryption mode, it's only a building block. Using ECB as demonstrated in this answer does not actually encrypt the string securely. Do not use ECB in your code. See Scott's answer for a good solution.
I got it on myself. Actually i found some answer on google and just modified something. The result is completely insecure however.
<?php
define("ENCRYPTION_KEY", "!##$%^&*");
$string = "This is the original data string!";
echo $encrypted = encrypt($string, ENCRYPTION_KEY);
echo "<br />";
echo $decrypted = decrypt($encrypted, ENCRYPTION_KEY);
/**
* Returns an encrypted & utf8-encoded
*/
function encrypt($pure_string, $encryption_key) {
$iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$encrypted_string = mcrypt_encrypt(MCRYPT_BLOWFISH, $encryption_key, utf8_encode($pure_string), MCRYPT_MODE_ECB, $iv);
return $encrypted_string;
}
/**
* Returns decrypted original string
*/
function decrypt($encrypted_string, $encryption_key) {
$iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$decrypted_string = mcrypt_decrypt(MCRYPT_BLOWFISH, $encryption_key, $encrypted_string, MCRYPT_MODE_ECB, $iv);
return $decrypted_string;
}
?>
For Laravel framework
If you are using Laravel framework then it's more easy to encrypt and decrypt with internal functions.
$string = 'Some text to be encrypted';
$encrypted = \Illuminate\Support\Facades\Crypt::encrypt($string);
$decrypted_string = \Illuminate\Support\Facades\Crypt::decrypt($encrypted);
var_dump($string);
var_dump($encrypted);
var_dump($decrypted_string);
Note: Be sure to set a 16, 24, or 32 character random string in the
key option of the config/app.php file. Otherwise, encrypted values
will not be secure.
Updated
PHP 7 ready version. It uses openssl_encrypt function from PHP OpenSSL Library.
class Openssl_EncryptDecrypt {
function encrypt ($pure_string, $encryption_key) {
$cipher = 'AES-256-CBC';
$options = OPENSSL_RAW_DATA;
$hash_algo = 'sha256';
$sha2len = 32;
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext_raw = openssl_encrypt($pure_string, $cipher, $encryption_key, $options, $iv);
$hmac = hash_hmac($hash_algo, $ciphertext_raw, $encryption_key, true);
return $iv.$hmac.$ciphertext_raw;
}
function decrypt ($encrypted_string, $encryption_key) {
$cipher = 'AES-256-CBC';
$options = OPENSSL_RAW_DATA;
$hash_algo = 'sha256';
$sha2len = 32;
$ivlen = openssl_cipher_iv_length($cipher);
$iv = substr($encrypted_string, 0, $ivlen);
$hmac = substr($encrypted_string, $ivlen, $sha2len);
$ciphertext_raw = substr($encrypted_string, $ivlen+$sha2len);
$original_plaintext = openssl_decrypt($ciphertext_raw, $cipher, $encryption_key, $options, $iv);
$calcmac = hash_hmac($hash_algo, $ciphertext_raw, $encryption_key, true);
if(function_exists('hash_equals')) {
if (hash_equals($hmac, $calcmac)) return $original_plaintext;
} else {
if ($this->hash_equals_custom($hmac, $calcmac)) return $original_plaintext;
}
}
/**
* (Optional)
* hash_equals() function polyfilling.
* PHP 5.6+ timing attack safe comparison
*/
function hash_equals_custom($knownString, $userString) {
if (function_exists('mb_strlen')) {
$kLen = mb_strlen($knownString, '8bit');
$uLen = mb_strlen($userString, '8bit');
} else {
$kLen = strlen($knownString);
$uLen = strlen($userString);
}
if ($kLen !== $uLen) {
return false;
}
$result = 0;
for ($i = 0; $i < $kLen; $i++) {
$result |= (ord($knownString[$i]) ^ ord($userString[$i]));
}
return 0 === $result;
}
}
define('ENCRYPTION_KEY', '__^%&Q#$&*!##$%^&*^__');
$string = "This is the original string!";
$OpensslEncryption = new Openssl_EncryptDecrypt;
$encrypted = $OpensslEncryption->encrypt($string, ENCRYPTION_KEY);
$decrypted = $OpensslEncryption->decrypt($encrypted, ENCRYPTION_KEY);
If you don't want to use library (which you should) then use something like this (PHP 7):
function sign($message, $key) {
return hash_hmac('sha256', $message, $key) . $message;
}
function verify($bundle, $key) {
return hash_equals(
hash_hmac('sha256', mb_substr($bundle, 64, null, '8bit'), $key),
mb_substr($bundle, 0, 64, '8bit')
);
}
function getKey($password, $keysize = 16) {
return hash_pbkdf2('sha256',$password,'some_token',100000,$keysize,true);
}
function encrypt($message, $password) {
$iv = random_bytes(16);
$key = getKey($password);
$result = sign(openssl_encrypt($message,'aes-256-ctr',$key,OPENSSL_RAW_DATA,$iv), $key);
return bin2hex($iv).bin2hex($result);
}
function decrypt($hash, $password) {
$iv = hex2bin(substr($hash, 0, 32));
$data = hex2bin(substr($hash, 32));
$key = getKey($password);
if (!verify($data, $key)) {
return null;
}
return openssl_decrypt(mb_substr($data, 64, null, '8bit'),'aes-256-ctr',$key,OPENSSL_RAW_DATA,$iv);
}
$string_to_encrypt='John Smith';
$password='password';
$encrypted_string=encrypt($string_to_encrypt, $password);
$decrypted_string=decrypt($encrypted_string, $password);
These are compact methods to encrypt / decrypt strings with PHP using AES256 CBC:
function encryptString($plaintext, $password, $encoding = null) {
$iv = openssl_random_pseudo_bytes(16);
$ciphertext = openssl_encrypt($plaintext, "AES-256-CBC", hash('sha256', $password, true), OPENSSL_RAW_DATA, $iv);
$hmac = hash_hmac('sha256', $ciphertext.$iv, hash('sha256', $password, true), true);
return $encoding == "hex" ? bin2hex($iv.$hmac.$ciphertext) : ($encoding == "base64" ? base64_encode($iv.$hmac.$ciphertext) : $iv.$hmac.$ciphertext);
}
function decryptString($ciphertext, $password, $encoding = null) {
$ciphertext = $encoding == "hex" ? hex2bin($ciphertext) : ($encoding == "base64" ? base64_decode($ciphertext) : $ciphertext);
if (!hash_equals(hash_hmac('sha256', substr($ciphertext, 48).substr($ciphertext, 0, 16), hash('sha256', $password, true), true), substr($ciphertext, 16, 32))) return null;
return openssl_decrypt(substr($ciphertext, 48), "AES-256-CBC", hash('sha256', $password, true), OPENSSL_RAW_DATA, substr($ciphertext, 0, 16));
}
Usage:
$enc = encryptString("mysecretText", "myPassword");
$dec = decryptString($enc, "myPassword");
EDIT: This is a new version of functions that use AES256 GCM and PBKDF2 as key derivation, more secure.
function str_encryptaesgcm($plaintext, $password, $encoding = null) {
if ($plaintext != null && $password != null) {
$keysalt = openssl_random_pseudo_bytes(16);
$key = hash_pbkdf2("sha512", $password, $keysalt, 20000, 32, true);
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length("aes-256-gcm"));
$tag = "";
$encryptedstring = openssl_encrypt($plaintext, "aes-256-gcm", $key, OPENSSL_RAW_DATA, $iv, $tag, "", 16);
return $encoding == "hex" ? bin2hex($keysalt.$iv.$encryptedstring.$tag) : ($encoding == "base64" ? base64_encode($keysalt.$iv.$encryptedstring.$tag) : $keysalt.$iv.$encryptedstring.$tag);
}
}
function str_decryptaesgcm($encryptedstring, $password, $encoding = null) {
if ($encryptedstring != null && $password != null) {
$encryptedstring = $encoding == "hex" ? hex2bin($encryptedstring) : ($encoding == "base64" ? base64_decode($encryptedstring) : $encryptedstring);
$keysalt = substr($encryptedstring, 0, 16);
$key = hash_pbkdf2("sha512", $password, $keysalt, 20000, 32, true);
$ivlength = openssl_cipher_iv_length("aes-256-gcm");
$iv = substr($encryptedstring, 16, $ivlength);
$tag = substr($encryptedstring, -16);
return openssl_decrypt(substr($encryptedstring, 16 + $ivlength, -16), "aes-256-gcm", $key, OPENSSL_RAW_DATA, $iv, $tag);
}
}
Usage:
$enc = str_encryptaesgcm("mysecretText", "myPassword", "base64"); // return a base64 encrypted string, you can also choose hex or null as encoding.
$dec = str_decryptaesgcm($enc, "myPassword", "base64");
Historical Note: This was written at the time of PHP4. This is what we call "legacy code" now.
I have left this answer for historical purposes - but some of the methods are now deprecated, DES encryption method is not a recommended practice, etc.
I have not updated this code for two reasons: 1) I no longer work with encryption methods by hand in PHP, and 2) this code still serves the purpose it was intended for: to demonstrate the minimum, simplistic concept of how encryption can work in PHP.
If you find a similarly simplistic, "PHP encryption for dummies" kind of source that can get people started in 10-20 lines of code or less, let me know in comments.
Beyond that, please enjoy this Classic Episode of early-era PHP4 minimalistic encryption answer.
Ideally you have - or can get - access to the mcrypt PHP library, as its certainly popular and very useful a variety of tasks. Here's a run down of the different kinds of encryption and some example code: Encryption Techniques in PHP
//Listing 3: Encrypting Data Using the mcrypt_ecb Function
<?php
echo("<h3> Symmetric Encryption </h3>");
$key_value = "KEYVALUE";
$plain_text = "PLAINTEXT";
$encrypted_text = mcrypt_ecb(MCRYPT_DES, $key_value, $plain_text, MCRYPT_ENCRYPT);
echo ("<p><b> Text after encryption : </b>");
echo ( $encrypted_text );
$decrypted_text = mcrypt_ecb(MCRYPT_DES, $key_value, $encrypted_text, MCRYPT_DECRYPT);
echo ("<p><b> Text after decryption : </b>");
echo ( $decrypted_text );
?>
A few warnings:
1) Never use reversible, or "symmetric" encryption when a one-way hash will do.
2) If the data is truly sensitive, like credit card or social security numbers, stop; you need more than any simple chunk of code will provide, but rather you need a crypto library designed for this purpose and a significant amount of time to research the methods necessary. Further, the software crypto is probably <10% of security of sensitive data. It's like rewiring a nuclear power station - accept that the task is dangerous and difficult and beyond your knowledge if that's the case. The financial penalties can be immense, so better to use a service and ship responsibility to them.
3) Any sort of easily implementable encryption, as listed here, can reasonably protect mildly important information that you want to keep from prying eyes or limit exposure in the case of accidental/intentional leak. But seeing as how the key is stored in plain text on the web server, if they can get the data they can get the decryption key.
Be that as it may, have fun :)
In PHP, Encryption and Decryption of a string is possible using one of the Cryptography Extensions called OpenSSL function for encrypt and decrypt.
openssl_encrypt() Function: The openssl_encrypt() function is used to encrypt the data.
Syntax is as follows :
string openssl_encrypt( string $data, string $method, string $key, $options = 0, string $iv, string $tag= NULL, string $aad, int $tag_length = 16 )
Parameters are as follows :
$data: It holds the string or data which need to be encrypted.
$method: The cipher method is adopted using openssl_get_cipher_methods() function.
$key: It holds the encryption key.
$options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
$iv: It holds the initialization vector which is not NULL.
$tag: It holds the authentication tag which is passed by reference when using AEAD cipher mode (GCM or CCM).
$aad: It holds the additional authentication data.
$tag_length: It holds the length of the authentication tag. The length of authentication tag lies between 4 to 16 for GCM mode.
Return Value: It returns the encrypted string on success or FALSE on failure.
openssl_decrypt() Function The openssl_decrypt() function is used to decrypt the data.
Syntax is as follows :
string openssl_decrypt( string $data, string $method, string $key, int $options = 0, string $iv, string $tag, string $aad)
Parameters are as follows :
$data: It holds the string or data which need to be encrypted.
$method: The cipher method is adopted using openssl_get_cipher_methods() function.
$key: It holds the encryption key.
$options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
$iv: It holds the initialization vector which is not NULL.
$tag: It holds the authentication tag using AEAD cipher mode (GCM or CCM). When authentication fails openssl_decrypt() returns FALSE.
$aad: It holds the additional authentication data.
Return Value: It returns the decrypted string on success or FALSE on failure.
Approach: First declare a string and store it into variable and use openssl_encrypt() function to encrypt the given string and use openssl_decrypt() function to descrypt the given string.
You can find the examples at : https://www.geeksforgeeks.org/how-to-encrypt-and-decrypt-a-php-string/
Below code work in php for all string with special character
// Encrypt text --
$token = "9611222007552";
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$enc_iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($cipher_method));
$crypted_token = openssl_encrypt($token, $cipher_method, $enc_key, 0, $enc_iv) . "::" . bin2hex($enc_iv);
echo $crypted_token;
//unset($token, $cipher_method, $enc_key, $enc_iv);
// Decrypt text --
list($crypted_token, $enc_iv) = explode("::", $crypted_token);
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$token = openssl_decrypt($crypted_token, $cipher_method, $enc_key, 0, hex2bin($enc_iv));
echo $token;
//unset($crypted_token, $cipher_method, $enc_key, $enc_iv);
What I mean is:
Original String + Salt or Key --> Encrypted String
Encrypted String + Salt or Key --> Decrypted (Original String)
Maybe something like:
"hello world!" + "ABCD1234" --> Encrypt --> "2a2ffa8f13220befbe30819047e23b2c" (may be, for e.g)
"2a2ffa8f13220befbe30819047e23b2c" --> Decrypt with "ABCD1234" --> "hello world!"
In PHP, how can you do this?
Attempted to use Crypt_Blowfish, but it didn't work for me.
Before you do anything further, seek to understand the difference between encryption and authentication, and why you probably want authenticated encryption rather than just encryption.
To implement authenticated encryption, you want to Encrypt then MAC. The order of encryption and authentication is very important! One of the existing answers to this question made this mistake; as do many cryptography libraries written in PHP.
You should avoid implementing your own cryptography, and instead use a secure library written by and reviewed by cryptography experts.
Update: PHP 7.2 now provides libsodium! For best security, update your systems to use PHP 7.2 or higher and only follow the libsodium advice in this answer.
Use libsodium if you have PECL access (or sodium_compat if you want libsodium without PECL); otherwise...
Use defuse/php-encryption; don't roll your own cryptography!
Both of the libraries linked above make it easy and painless to implement authenticated encryption into your own libraries.
If you still want to write and deploy your own cryptography library, against the conventional wisdom of every cryptography expert on the Internet, these are the steps you would have to take.
Encryption:
Encrypt using AES in CTR mode. You may also use GCM (which removes the need for a separate MAC). Additionally, ChaCha20 and Salsa20 (provided by libsodium) are stream ciphers and do not need special modes.
Unless you chose GCM above, you should authenticate the ciphertext with HMAC-SHA-256 (or, for the stream ciphers, Poly1305 -- most libsodium APIs do this for you). The MAC should cover the IV as well as the ciphertext!
Decryption:
Unless Poly1305 or GCM is used, recalculate the MAC of the ciphertext and compare it with the MAC that was sent using hash_equals(). If it fails, abort.
Decrypt the message.
Other Design Considerations:
Do not compress anything ever. Ciphertext is not compressible; compressing plaintext before encryption can lead to information leaks (e.g. CRIME and BREACH on TLS).
Make sure you use mb_strlen() and mb_substr(), using the '8bit' character set mode to prevent mbstring.func_overload issues.
IVs should be generating using a CSPRNG; If you're using mcrypt_create_iv(), DO NOT USE MCRYPT_RAND!
Also check out random_compat.
Unless you're using an AEAD construct, ALWAYS encrypt then MAC!
bin2hex(), base64_encode(), etc. may leak information about your encryption keys via cache timing. Avoid them if possible.
Even if you follow the advice given here, a lot can go wrong with cryptography. Always have a cryptography expert review your implementation. If you are not fortunate enough to be personal friends with a cryptography student at your local university, you can always try the Cryptography Stack Exchange forum for advice.
If you need a professional analysis of your implementation, you can always hire a reputable team of security consultants to review your PHP cryptography code (disclosure: my employer).
Important: When to Not Use Encryption
Don't encrypt passwords. You want to hash them instead, using one of these password-hashing algorithms:
Argon2
scrypt
bcrypt
PBKDF2-SHA256 with 86,000 iterations
Never use a general-purpose hash function (MD5, SHA256) for password storage.
Don't encrypt URL Parameters. It's the wrong tool for the job.
PHP String Encryption Example with Libsodium
If you are on PHP < 7.2 or otherwise do not have libsodium installed, you can use sodium_compat to accomplish the same result (albeit slower).
<?php
declare(strict_types=1);
/**
* Encrypt a message
*
* #param string $message - message to encrypt
* #param string $key - encryption key
* #return string
* #throws RangeException
*/
function safeEncrypt(string $message, string $key): string
{
if (mb_strlen($key, '8bit') !== SODIUM_CRYPTO_SECRETBOX_KEYBYTES) {
throw new RangeException('Key is not the correct size (must be 32 bytes).');
}
$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
$cipher = base64_encode(
$nonce.
sodium_crypto_secretbox(
$message,
$nonce,
$key
)
);
sodium_memzero($message);
sodium_memzero($key);
return $cipher;
}
/**
* Decrypt a message
*
* #param string $encrypted - message encrypted with safeEncrypt()
* #param string $key - encryption key
* #return string
* #throws Exception
*/
function safeDecrypt(string $encrypted, string $key): string
{
$decoded = base64_decode($encrypted);
$nonce = mb_substr($decoded, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, '8bit');
$ciphertext = mb_substr($decoded, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, null, '8bit');
$plain = sodium_crypto_secretbox_open(
$ciphertext,
$nonce,
$key
);
if (!is_string($plain)) {
throw new Exception('Invalid MAC');
}
sodium_memzero($ciphertext);
sodium_memzero($key);
return $plain;
}
Then to test it out:
<?php
// This refers to the previous code block.
require "safeCrypto.php";
// Do this once then store it somehow:
$key = random_bytes(SODIUM_CRYPTO_SECRETBOX_KEYBYTES);
$message = 'We are all living in a yellow submarine';
$ciphertext = safeEncrypt($message, $key);
$plaintext = safeDecrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
Halite - Libsodium Made Easier
One of the projects I've been working on is an encryption library called Halite, which aims to make libsodium easier and more intuitive.
<?php
use \ParagonIE\Halite\KeyFactory;
use \ParagonIE\Halite\Symmetric\Crypto as SymmetricCrypto;
// Generate a new random symmetric-key encryption key. You're going to want to store this:
$key = new KeyFactory::generateEncryptionKey();
// To save your encryption key:
KeyFactory::save($key, '/path/to/secret.key');
// To load it again:
$loadedkey = KeyFactory::loadEncryptionKey('/path/to/secret.key');
$message = 'We are all living in a yellow submarine';
$ciphertext = SymmetricCrypto::encrypt($message, $key);
$plaintext = SymmetricCrypto::decrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
All of the underlying cryptography is handled by libsodium.
Example with defuse/php-encryption
<?php
/**
* This requires https://github.com/defuse/php-encryption
* php composer.phar require defuse/php-encryption
*/
use Defuse\Crypto\Crypto;
use Defuse\Crypto\Key;
require "vendor/autoload.php";
// Do this once then store it somehow:
$key = Key::createNewRandomKey();
$message = 'We are all living in a yellow submarine';
$ciphertext = Crypto::encrypt($message, $key);
$plaintext = Crypto::decrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
Note: Crypto::encrypt() returns hex-encoded output.
Encryption Key Management
If you're tempted to use a "password", stop right now. You need a random 128-bit encryption key, not a human memorable password.
You can store an encryption key for long-term use like so:
$storeMe = bin2hex($key);
And, on demand, you can retrieve it like so:
$key = hex2bin($storeMe);
I strongly recommend just storing a randomly generated key for long-term use instead of any sort of password as the key (or to derive the key).
If you're using Defuse's library:
$string = $keyObject->saveToAsciiSafeString()
$loaded = Key::loadFromAsciiSafeString($string);
"But I really want to use a password."
That's a bad idea, but okay, here's how to do it safely.
First, generate a random key and store it in a constant.
/**
* Replace this with your own salt!
* Use bin2hex() then add \x before every 2 hex characters, like so:
*/
define('MY_PBKDF2_SALT', "\x2d\xb7\x68\x1a\x28\x15\xbe\x06\x33\xa0\x7e\x0e\x8f\x79\xd5\xdf");
Note that you're adding extra work and could just use this constant as the key and save yourself a lot of heartache!
Then use PBKDF2 (like so) to derive a suitable encryption key from your password rather than encrypting with your password directly.
/**
* Get an AES key from a static password and a secret salt
*
* #param string $password Your weak password here
* #param int $keysize Number of bytes in encryption key
*/
function getKeyFromPassword($password, $keysize = 16)
{
return hash_pbkdf2(
'sha256',
$password,
MY_PBKDF2_SALT,
100000, // Number of iterations
$keysize,
true
);
}
Don't just use a 16-character password. Your encryption key will be comically broken.
I'm late to the party, but searching for the correct way to do it I came across this page it was one of the top Google search returns, so I will like to share my view on the problem, which I consider it to be up to date at the time of writing this post (beginning of 2017). From PHP 7.1.0 the mcrypt_decrypt and mcrypt_encrypt is going to be deprecated, so building future proof code should use openssl_encrypt and openssl_decrypt
You can do something like:
$string_to_encrypt="Test";
$password="password";
$encrypted_string=openssl_encrypt($string_to_encrypt,"AES-128-ECB",$password);
$decrypted_string=openssl_decrypt($encrypted_string,"AES-128-ECB",$password);
Important: This uses ECB mode, which isn't secure. If you want a simple solution without taking a crash course in cryptography engineering, don't write it yourself, just use a library.
You can use any other chipper methods as well, depending on your security need. To find out the available chipper methods please see the openssl_get_cipher_methods function.
What not to do
WARNING:
This answer uses ECB. ECB is not an encryption mode, it's only a building block. Using ECB as demonstrated in this answer does not actually encrypt the string securely. Do not use ECB in your code. See Scott's answer for a good solution.
I got it on myself. Actually i found some answer on google and just modified something. The result is completely insecure however.
<?php
define("ENCRYPTION_KEY", "!##$%^&*");
$string = "This is the original data string!";
echo $encrypted = encrypt($string, ENCRYPTION_KEY);
echo "<br />";
echo $decrypted = decrypt($encrypted, ENCRYPTION_KEY);
/**
* Returns an encrypted & utf8-encoded
*/
function encrypt($pure_string, $encryption_key) {
$iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$encrypted_string = mcrypt_encrypt(MCRYPT_BLOWFISH, $encryption_key, utf8_encode($pure_string), MCRYPT_MODE_ECB, $iv);
return $encrypted_string;
}
/**
* Returns decrypted original string
*/
function decrypt($encrypted_string, $encryption_key) {
$iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$decrypted_string = mcrypt_decrypt(MCRYPT_BLOWFISH, $encryption_key, $encrypted_string, MCRYPT_MODE_ECB, $iv);
return $decrypted_string;
}
?>
For Laravel framework
If you are using Laravel framework then it's more easy to encrypt and decrypt with internal functions.
$string = 'Some text to be encrypted';
$encrypted = \Illuminate\Support\Facades\Crypt::encrypt($string);
$decrypted_string = \Illuminate\Support\Facades\Crypt::decrypt($encrypted);
var_dump($string);
var_dump($encrypted);
var_dump($decrypted_string);
Note: Be sure to set a 16, 24, or 32 character random string in the
key option of the config/app.php file. Otherwise, encrypted values
will not be secure.
Updated
PHP 7 ready version. It uses openssl_encrypt function from PHP OpenSSL Library.
class Openssl_EncryptDecrypt {
function encrypt ($pure_string, $encryption_key) {
$cipher = 'AES-256-CBC';
$options = OPENSSL_RAW_DATA;
$hash_algo = 'sha256';
$sha2len = 32;
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext_raw = openssl_encrypt($pure_string, $cipher, $encryption_key, $options, $iv);
$hmac = hash_hmac($hash_algo, $ciphertext_raw, $encryption_key, true);
return $iv.$hmac.$ciphertext_raw;
}
function decrypt ($encrypted_string, $encryption_key) {
$cipher = 'AES-256-CBC';
$options = OPENSSL_RAW_DATA;
$hash_algo = 'sha256';
$sha2len = 32;
$ivlen = openssl_cipher_iv_length($cipher);
$iv = substr($encrypted_string, 0, $ivlen);
$hmac = substr($encrypted_string, $ivlen, $sha2len);
$ciphertext_raw = substr($encrypted_string, $ivlen+$sha2len);
$original_plaintext = openssl_decrypt($ciphertext_raw, $cipher, $encryption_key, $options, $iv);
$calcmac = hash_hmac($hash_algo, $ciphertext_raw, $encryption_key, true);
if(function_exists('hash_equals')) {
if (hash_equals($hmac, $calcmac)) return $original_plaintext;
} else {
if ($this->hash_equals_custom($hmac, $calcmac)) return $original_plaintext;
}
}
/**
* (Optional)
* hash_equals() function polyfilling.
* PHP 5.6+ timing attack safe comparison
*/
function hash_equals_custom($knownString, $userString) {
if (function_exists('mb_strlen')) {
$kLen = mb_strlen($knownString, '8bit');
$uLen = mb_strlen($userString, '8bit');
} else {
$kLen = strlen($knownString);
$uLen = strlen($userString);
}
if ($kLen !== $uLen) {
return false;
}
$result = 0;
for ($i = 0; $i < $kLen; $i++) {
$result |= (ord($knownString[$i]) ^ ord($userString[$i]));
}
return 0 === $result;
}
}
define('ENCRYPTION_KEY', '__^%&Q#$&*!##$%^&*^__');
$string = "This is the original string!";
$OpensslEncryption = new Openssl_EncryptDecrypt;
$encrypted = $OpensslEncryption->encrypt($string, ENCRYPTION_KEY);
$decrypted = $OpensslEncryption->decrypt($encrypted, ENCRYPTION_KEY);
If you don't want to use library (which you should) then use something like this (PHP 7):
function sign($message, $key) {
return hash_hmac('sha256', $message, $key) . $message;
}
function verify($bundle, $key) {
return hash_equals(
hash_hmac('sha256', mb_substr($bundle, 64, null, '8bit'), $key),
mb_substr($bundle, 0, 64, '8bit')
);
}
function getKey($password, $keysize = 16) {
return hash_pbkdf2('sha256',$password,'some_token',100000,$keysize,true);
}
function encrypt($message, $password) {
$iv = random_bytes(16);
$key = getKey($password);
$result = sign(openssl_encrypt($message,'aes-256-ctr',$key,OPENSSL_RAW_DATA,$iv), $key);
return bin2hex($iv).bin2hex($result);
}
function decrypt($hash, $password) {
$iv = hex2bin(substr($hash, 0, 32));
$data = hex2bin(substr($hash, 32));
$key = getKey($password);
if (!verify($data, $key)) {
return null;
}
return openssl_decrypt(mb_substr($data, 64, null, '8bit'),'aes-256-ctr',$key,OPENSSL_RAW_DATA,$iv);
}
$string_to_encrypt='John Smith';
$password='password';
$encrypted_string=encrypt($string_to_encrypt, $password);
$decrypted_string=decrypt($encrypted_string, $password);
These are compact methods to encrypt / decrypt strings with PHP using AES256 CBC:
function encryptString($plaintext, $password, $encoding = null) {
$iv = openssl_random_pseudo_bytes(16);
$ciphertext = openssl_encrypt($plaintext, "AES-256-CBC", hash('sha256', $password, true), OPENSSL_RAW_DATA, $iv);
$hmac = hash_hmac('sha256', $ciphertext.$iv, hash('sha256', $password, true), true);
return $encoding == "hex" ? bin2hex($iv.$hmac.$ciphertext) : ($encoding == "base64" ? base64_encode($iv.$hmac.$ciphertext) : $iv.$hmac.$ciphertext);
}
function decryptString($ciphertext, $password, $encoding = null) {
$ciphertext = $encoding == "hex" ? hex2bin($ciphertext) : ($encoding == "base64" ? base64_decode($ciphertext) : $ciphertext);
if (!hash_equals(hash_hmac('sha256', substr($ciphertext, 48).substr($ciphertext, 0, 16), hash('sha256', $password, true), true), substr($ciphertext, 16, 32))) return null;
return openssl_decrypt(substr($ciphertext, 48), "AES-256-CBC", hash('sha256', $password, true), OPENSSL_RAW_DATA, substr($ciphertext, 0, 16));
}
Usage:
$enc = encryptString("mysecretText", "myPassword");
$dec = decryptString($enc, "myPassword");
EDIT: This is a new version of functions that use AES256 GCM and PBKDF2 as key derivation, more secure.
function str_encryptaesgcm($plaintext, $password, $encoding = null) {
if ($plaintext != null && $password != null) {
$keysalt = openssl_random_pseudo_bytes(16);
$key = hash_pbkdf2("sha512", $password, $keysalt, 20000, 32, true);
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length("aes-256-gcm"));
$tag = "";
$encryptedstring = openssl_encrypt($plaintext, "aes-256-gcm", $key, OPENSSL_RAW_DATA, $iv, $tag, "", 16);
return $encoding == "hex" ? bin2hex($keysalt.$iv.$encryptedstring.$tag) : ($encoding == "base64" ? base64_encode($keysalt.$iv.$encryptedstring.$tag) : $keysalt.$iv.$encryptedstring.$tag);
}
}
function str_decryptaesgcm($encryptedstring, $password, $encoding = null) {
if ($encryptedstring != null && $password != null) {
$encryptedstring = $encoding == "hex" ? hex2bin($encryptedstring) : ($encoding == "base64" ? base64_decode($encryptedstring) : $encryptedstring);
$keysalt = substr($encryptedstring, 0, 16);
$key = hash_pbkdf2("sha512", $password, $keysalt, 20000, 32, true);
$ivlength = openssl_cipher_iv_length("aes-256-gcm");
$iv = substr($encryptedstring, 16, $ivlength);
$tag = substr($encryptedstring, -16);
return openssl_decrypt(substr($encryptedstring, 16 + $ivlength, -16), "aes-256-gcm", $key, OPENSSL_RAW_DATA, $iv, $tag);
}
}
Usage:
$enc = str_encryptaesgcm("mysecretText", "myPassword", "base64"); // return a base64 encrypted string, you can also choose hex or null as encoding.
$dec = str_decryptaesgcm($enc, "myPassword", "base64");
Historical Note: This was written at the time of PHP4. This is what we call "legacy code" now.
I have left this answer for historical purposes - but some of the methods are now deprecated, DES encryption method is not a recommended practice, etc.
I have not updated this code for two reasons: 1) I no longer work with encryption methods by hand in PHP, and 2) this code still serves the purpose it was intended for: to demonstrate the minimum, simplistic concept of how encryption can work in PHP.
If you find a similarly simplistic, "PHP encryption for dummies" kind of source that can get people started in 10-20 lines of code or less, let me know in comments.
Beyond that, please enjoy this Classic Episode of early-era PHP4 minimalistic encryption answer.
Ideally you have - or can get - access to the mcrypt PHP library, as its certainly popular and very useful a variety of tasks. Here's a run down of the different kinds of encryption and some example code: Encryption Techniques in PHP
//Listing 3: Encrypting Data Using the mcrypt_ecb Function
<?php
echo("<h3> Symmetric Encryption </h3>");
$key_value = "KEYVALUE";
$plain_text = "PLAINTEXT";
$encrypted_text = mcrypt_ecb(MCRYPT_DES, $key_value, $plain_text, MCRYPT_ENCRYPT);
echo ("<p><b> Text after encryption : </b>");
echo ( $encrypted_text );
$decrypted_text = mcrypt_ecb(MCRYPT_DES, $key_value, $encrypted_text, MCRYPT_DECRYPT);
echo ("<p><b> Text after decryption : </b>");
echo ( $decrypted_text );
?>
A few warnings:
1) Never use reversible, or "symmetric" encryption when a one-way hash will do.
2) If the data is truly sensitive, like credit card or social security numbers, stop; you need more than any simple chunk of code will provide, but rather you need a crypto library designed for this purpose and a significant amount of time to research the methods necessary. Further, the software crypto is probably <10% of security of sensitive data. It's like rewiring a nuclear power station - accept that the task is dangerous and difficult and beyond your knowledge if that's the case. The financial penalties can be immense, so better to use a service and ship responsibility to them.
3) Any sort of easily implementable encryption, as listed here, can reasonably protect mildly important information that you want to keep from prying eyes or limit exposure in the case of accidental/intentional leak. But seeing as how the key is stored in plain text on the web server, if they can get the data they can get the decryption key.
Be that as it may, have fun :)
In PHP, Encryption and Decryption of a string is possible using one of the Cryptography Extensions called OpenSSL function for encrypt and decrypt.
openssl_encrypt() Function: The openssl_encrypt() function is used to encrypt the data.
Syntax is as follows :
string openssl_encrypt( string $data, string $method, string $key, $options = 0, string $iv, string $tag= NULL, string $aad, int $tag_length = 16 )
Parameters are as follows :
$data: It holds the string or data which need to be encrypted.
$method: The cipher method is adopted using openssl_get_cipher_methods() function.
$key: It holds the encryption key.
$options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
$iv: It holds the initialization vector which is not NULL.
$tag: It holds the authentication tag which is passed by reference when using AEAD cipher mode (GCM or CCM).
$aad: It holds the additional authentication data.
$tag_length: It holds the length of the authentication tag. The length of authentication tag lies between 4 to 16 for GCM mode.
Return Value: It returns the encrypted string on success or FALSE on failure.
openssl_decrypt() Function The openssl_decrypt() function is used to decrypt the data.
Syntax is as follows :
string openssl_decrypt( string $data, string $method, string $key, int $options = 0, string $iv, string $tag, string $aad)
Parameters are as follows :
$data: It holds the string or data which need to be encrypted.
$method: The cipher method is adopted using openssl_get_cipher_methods() function.
$key: It holds the encryption key.
$options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
$iv: It holds the initialization vector which is not NULL.
$tag: It holds the authentication tag using AEAD cipher mode (GCM or CCM). When authentication fails openssl_decrypt() returns FALSE.
$aad: It holds the additional authentication data.
Return Value: It returns the decrypted string on success or FALSE on failure.
Approach: First declare a string and store it into variable and use openssl_encrypt() function to encrypt the given string and use openssl_decrypt() function to descrypt the given string.
You can find the examples at : https://www.geeksforgeeks.org/how-to-encrypt-and-decrypt-a-php-string/
Below code work in php for all string with special character
// Encrypt text --
$token = "9611222007552";
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$enc_iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($cipher_method));
$crypted_token = openssl_encrypt($token, $cipher_method, $enc_key, 0, $enc_iv) . "::" . bin2hex($enc_iv);
echo $crypted_token;
//unset($token, $cipher_method, $enc_key, $enc_iv);
// Decrypt text --
list($crypted_token, $enc_iv) = explode("::", $crypted_token);
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$token = openssl_decrypt($crypted_token, $cipher_method, $enc_key, 0, hex2bin($enc_iv));
echo $token;
//unset($crypted_token, $cipher_method, $enc_key, $enc_iv);
What I mean is:
Original String + Salt or Key --> Encrypted String
Encrypted String + Salt or Key --> Decrypted (Original String)
Maybe something like:
"hello world!" + "ABCD1234" --> Encrypt --> "2a2ffa8f13220befbe30819047e23b2c" (may be, for e.g)
"2a2ffa8f13220befbe30819047e23b2c" --> Decrypt with "ABCD1234" --> "hello world!"
In PHP, how can you do this?
Attempted to use Crypt_Blowfish, but it didn't work for me.
Before you do anything further, seek to understand the difference between encryption and authentication, and why you probably want authenticated encryption rather than just encryption.
To implement authenticated encryption, you want to Encrypt then MAC. The order of encryption and authentication is very important! One of the existing answers to this question made this mistake; as do many cryptography libraries written in PHP.
You should avoid implementing your own cryptography, and instead use a secure library written by and reviewed by cryptography experts.
Update: PHP 7.2 now provides libsodium! For best security, update your systems to use PHP 7.2 or higher and only follow the libsodium advice in this answer.
Use libsodium if you have PECL access (or sodium_compat if you want libsodium without PECL); otherwise...
Use defuse/php-encryption; don't roll your own cryptography!
Both of the libraries linked above make it easy and painless to implement authenticated encryption into your own libraries.
If you still want to write and deploy your own cryptography library, against the conventional wisdom of every cryptography expert on the Internet, these are the steps you would have to take.
Encryption:
Encrypt using AES in CTR mode. You may also use GCM (which removes the need for a separate MAC). Additionally, ChaCha20 and Salsa20 (provided by libsodium) are stream ciphers and do not need special modes.
Unless you chose GCM above, you should authenticate the ciphertext with HMAC-SHA-256 (or, for the stream ciphers, Poly1305 -- most libsodium APIs do this for you). The MAC should cover the IV as well as the ciphertext!
Decryption:
Unless Poly1305 or GCM is used, recalculate the MAC of the ciphertext and compare it with the MAC that was sent using hash_equals(). If it fails, abort.
Decrypt the message.
Other Design Considerations:
Do not compress anything ever. Ciphertext is not compressible; compressing plaintext before encryption can lead to information leaks (e.g. CRIME and BREACH on TLS).
Make sure you use mb_strlen() and mb_substr(), using the '8bit' character set mode to prevent mbstring.func_overload issues.
IVs should be generating using a CSPRNG; If you're using mcrypt_create_iv(), DO NOT USE MCRYPT_RAND!
Also check out random_compat.
Unless you're using an AEAD construct, ALWAYS encrypt then MAC!
bin2hex(), base64_encode(), etc. may leak information about your encryption keys via cache timing. Avoid them if possible.
Even if you follow the advice given here, a lot can go wrong with cryptography. Always have a cryptography expert review your implementation. If you are not fortunate enough to be personal friends with a cryptography student at your local university, you can always try the Cryptography Stack Exchange forum for advice.
If you need a professional analysis of your implementation, you can always hire a reputable team of security consultants to review your PHP cryptography code (disclosure: my employer).
Important: When to Not Use Encryption
Don't encrypt passwords. You want to hash them instead, using one of these password-hashing algorithms:
Argon2
scrypt
bcrypt
PBKDF2-SHA256 with 86,000 iterations
Never use a general-purpose hash function (MD5, SHA256) for password storage.
Don't encrypt URL Parameters. It's the wrong tool for the job.
PHP String Encryption Example with Libsodium
If you are on PHP < 7.2 or otherwise do not have libsodium installed, you can use sodium_compat to accomplish the same result (albeit slower).
<?php
declare(strict_types=1);
/**
* Encrypt a message
*
* #param string $message - message to encrypt
* #param string $key - encryption key
* #return string
* #throws RangeException
*/
function safeEncrypt(string $message, string $key): string
{
if (mb_strlen($key, '8bit') !== SODIUM_CRYPTO_SECRETBOX_KEYBYTES) {
throw new RangeException('Key is not the correct size (must be 32 bytes).');
}
$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
$cipher = base64_encode(
$nonce.
sodium_crypto_secretbox(
$message,
$nonce,
$key
)
);
sodium_memzero($message);
sodium_memzero($key);
return $cipher;
}
/**
* Decrypt a message
*
* #param string $encrypted - message encrypted with safeEncrypt()
* #param string $key - encryption key
* #return string
* #throws Exception
*/
function safeDecrypt(string $encrypted, string $key): string
{
$decoded = base64_decode($encrypted);
$nonce = mb_substr($decoded, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, '8bit');
$ciphertext = mb_substr($decoded, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, null, '8bit');
$plain = sodium_crypto_secretbox_open(
$ciphertext,
$nonce,
$key
);
if (!is_string($plain)) {
throw new Exception('Invalid MAC');
}
sodium_memzero($ciphertext);
sodium_memzero($key);
return $plain;
}
Then to test it out:
<?php
// This refers to the previous code block.
require "safeCrypto.php";
// Do this once then store it somehow:
$key = random_bytes(SODIUM_CRYPTO_SECRETBOX_KEYBYTES);
$message = 'We are all living in a yellow submarine';
$ciphertext = safeEncrypt($message, $key);
$plaintext = safeDecrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
Halite - Libsodium Made Easier
One of the projects I've been working on is an encryption library called Halite, which aims to make libsodium easier and more intuitive.
<?php
use \ParagonIE\Halite\KeyFactory;
use \ParagonIE\Halite\Symmetric\Crypto as SymmetricCrypto;
// Generate a new random symmetric-key encryption key. You're going to want to store this:
$key = new KeyFactory::generateEncryptionKey();
// To save your encryption key:
KeyFactory::save($key, '/path/to/secret.key');
// To load it again:
$loadedkey = KeyFactory::loadEncryptionKey('/path/to/secret.key');
$message = 'We are all living in a yellow submarine';
$ciphertext = SymmetricCrypto::encrypt($message, $key);
$plaintext = SymmetricCrypto::decrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
All of the underlying cryptography is handled by libsodium.
Example with defuse/php-encryption
<?php
/**
* This requires https://github.com/defuse/php-encryption
* php composer.phar require defuse/php-encryption
*/
use Defuse\Crypto\Crypto;
use Defuse\Crypto\Key;
require "vendor/autoload.php";
// Do this once then store it somehow:
$key = Key::createNewRandomKey();
$message = 'We are all living in a yellow submarine';
$ciphertext = Crypto::encrypt($message, $key);
$plaintext = Crypto::decrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
Note: Crypto::encrypt() returns hex-encoded output.
Encryption Key Management
If you're tempted to use a "password", stop right now. You need a random 128-bit encryption key, not a human memorable password.
You can store an encryption key for long-term use like so:
$storeMe = bin2hex($key);
And, on demand, you can retrieve it like so:
$key = hex2bin($storeMe);
I strongly recommend just storing a randomly generated key for long-term use instead of any sort of password as the key (or to derive the key).
If you're using Defuse's library:
$string = $keyObject->saveToAsciiSafeString()
$loaded = Key::loadFromAsciiSafeString($string);
"But I really want to use a password."
That's a bad idea, but okay, here's how to do it safely.
First, generate a random key and store it in a constant.
/**
* Replace this with your own salt!
* Use bin2hex() then add \x before every 2 hex characters, like so:
*/
define('MY_PBKDF2_SALT', "\x2d\xb7\x68\x1a\x28\x15\xbe\x06\x33\xa0\x7e\x0e\x8f\x79\xd5\xdf");
Note that you're adding extra work and could just use this constant as the key and save yourself a lot of heartache!
Then use PBKDF2 (like so) to derive a suitable encryption key from your password rather than encrypting with your password directly.
/**
* Get an AES key from a static password and a secret salt
*
* #param string $password Your weak password here
* #param int $keysize Number of bytes in encryption key
*/
function getKeyFromPassword($password, $keysize = 16)
{
return hash_pbkdf2(
'sha256',
$password,
MY_PBKDF2_SALT,
100000, // Number of iterations
$keysize,
true
);
}
Don't just use a 16-character password. Your encryption key will be comically broken.
I'm late to the party, but searching for the correct way to do it I came across this page it was one of the top Google search returns, so I will like to share my view on the problem, which I consider it to be up to date at the time of writing this post (beginning of 2017). From PHP 7.1.0 the mcrypt_decrypt and mcrypt_encrypt is going to be deprecated, so building future proof code should use openssl_encrypt and openssl_decrypt
You can do something like:
$string_to_encrypt="Test";
$password="password";
$encrypted_string=openssl_encrypt($string_to_encrypt,"AES-128-ECB",$password);
$decrypted_string=openssl_decrypt($encrypted_string,"AES-128-ECB",$password);
Important: This uses ECB mode, which isn't secure. If you want a simple solution without taking a crash course in cryptography engineering, don't write it yourself, just use a library.
You can use any other chipper methods as well, depending on your security need. To find out the available chipper methods please see the openssl_get_cipher_methods function.
What not to do
WARNING:
This answer uses ECB. ECB is not an encryption mode, it's only a building block. Using ECB as demonstrated in this answer does not actually encrypt the string securely. Do not use ECB in your code. See Scott's answer for a good solution.
I got it on myself. Actually i found some answer on google and just modified something. The result is completely insecure however.
<?php
define("ENCRYPTION_KEY", "!##$%^&*");
$string = "This is the original data string!";
echo $encrypted = encrypt($string, ENCRYPTION_KEY);
echo "<br />";
echo $decrypted = decrypt($encrypted, ENCRYPTION_KEY);
/**
* Returns an encrypted & utf8-encoded
*/
function encrypt($pure_string, $encryption_key) {
$iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$encrypted_string = mcrypt_encrypt(MCRYPT_BLOWFISH, $encryption_key, utf8_encode($pure_string), MCRYPT_MODE_ECB, $iv);
return $encrypted_string;
}
/**
* Returns decrypted original string
*/
function decrypt($encrypted_string, $encryption_key) {
$iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$decrypted_string = mcrypt_decrypt(MCRYPT_BLOWFISH, $encryption_key, $encrypted_string, MCRYPT_MODE_ECB, $iv);
return $decrypted_string;
}
?>
For Laravel framework
If you are using Laravel framework then it's more easy to encrypt and decrypt with internal functions.
$string = 'Some text to be encrypted';
$encrypted = \Illuminate\Support\Facades\Crypt::encrypt($string);
$decrypted_string = \Illuminate\Support\Facades\Crypt::decrypt($encrypted);
var_dump($string);
var_dump($encrypted);
var_dump($decrypted_string);
Note: Be sure to set a 16, 24, or 32 character random string in the
key option of the config/app.php file. Otherwise, encrypted values
will not be secure.
Updated
PHP 7 ready version. It uses openssl_encrypt function from PHP OpenSSL Library.
class Openssl_EncryptDecrypt {
function encrypt ($pure_string, $encryption_key) {
$cipher = 'AES-256-CBC';
$options = OPENSSL_RAW_DATA;
$hash_algo = 'sha256';
$sha2len = 32;
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext_raw = openssl_encrypt($pure_string, $cipher, $encryption_key, $options, $iv);
$hmac = hash_hmac($hash_algo, $ciphertext_raw, $encryption_key, true);
return $iv.$hmac.$ciphertext_raw;
}
function decrypt ($encrypted_string, $encryption_key) {
$cipher = 'AES-256-CBC';
$options = OPENSSL_RAW_DATA;
$hash_algo = 'sha256';
$sha2len = 32;
$ivlen = openssl_cipher_iv_length($cipher);
$iv = substr($encrypted_string, 0, $ivlen);
$hmac = substr($encrypted_string, $ivlen, $sha2len);
$ciphertext_raw = substr($encrypted_string, $ivlen+$sha2len);
$original_plaintext = openssl_decrypt($ciphertext_raw, $cipher, $encryption_key, $options, $iv);
$calcmac = hash_hmac($hash_algo, $ciphertext_raw, $encryption_key, true);
if(function_exists('hash_equals')) {
if (hash_equals($hmac, $calcmac)) return $original_plaintext;
} else {
if ($this->hash_equals_custom($hmac, $calcmac)) return $original_plaintext;
}
}
/**
* (Optional)
* hash_equals() function polyfilling.
* PHP 5.6+ timing attack safe comparison
*/
function hash_equals_custom($knownString, $userString) {
if (function_exists('mb_strlen')) {
$kLen = mb_strlen($knownString, '8bit');
$uLen = mb_strlen($userString, '8bit');
} else {
$kLen = strlen($knownString);
$uLen = strlen($userString);
}
if ($kLen !== $uLen) {
return false;
}
$result = 0;
for ($i = 0; $i < $kLen; $i++) {
$result |= (ord($knownString[$i]) ^ ord($userString[$i]));
}
return 0 === $result;
}
}
define('ENCRYPTION_KEY', '__^%&Q#$&*!##$%^&*^__');
$string = "This is the original string!";
$OpensslEncryption = new Openssl_EncryptDecrypt;
$encrypted = $OpensslEncryption->encrypt($string, ENCRYPTION_KEY);
$decrypted = $OpensslEncryption->decrypt($encrypted, ENCRYPTION_KEY);
If you don't want to use library (which you should) then use something like this (PHP 7):
function sign($message, $key) {
return hash_hmac('sha256', $message, $key) . $message;
}
function verify($bundle, $key) {
return hash_equals(
hash_hmac('sha256', mb_substr($bundle, 64, null, '8bit'), $key),
mb_substr($bundle, 0, 64, '8bit')
);
}
function getKey($password, $keysize = 16) {
return hash_pbkdf2('sha256',$password,'some_token',100000,$keysize,true);
}
function encrypt($message, $password) {
$iv = random_bytes(16);
$key = getKey($password);
$result = sign(openssl_encrypt($message,'aes-256-ctr',$key,OPENSSL_RAW_DATA,$iv), $key);
return bin2hex($iv).bin2hex($result);
}
function decrypt($hash, $password) {
$iv = hex2bin(substr($hash, 0, 32));
$data = hex2bin(substr($hash, 32));
$key = getKey($password);
if (!verify($data, $key)) {
return null;
}
return openssl_decrypt(mb_substr($data, 64, null, '8bit'),'aes-256-ctr',$key,OPENSSL_RAW_DATA,$iv);
}
$string_to_encrypt='John Smith';
$password='password';
$encrypted_string=encrypt($string_to_encrypt, $password);
$decrypted_string=decrypt($encrypted_string, $password);
These are compact methods to encrypt / decrypt strings with PHP using AES256 CBC:
function encryptString($plaintext, $password, $encoding = null) {
$iv = openssl_random_pseudo_bytes(16);
$ciphertext = openssl_encrypt($plaintext, "AES-256-CBC", hash('sha256', $password, true), OPENSSL_RAW_DATA, $iv);
$hmac = hash_hmac('sha256', $ciphertext.$iv, hash('sha256', $password, true), true);
return $encoding == "hex" ? bin2hex($iv.$hmac.$ciphertext) : ($encoding == "base64" ? base64_encode($iv.$hmac.$ciphertext) : $iv.$hmac.$ciphertext);
}
function decryptString($ciphertext, $password, $encoding = null) {
$ciphertext = $encoding == "hex" ? hex2bin($ciphertext) : ($encoding == "base64" ? base64_decode($ciphertext) : $ciphertext);
if (!hash_equals(hash_hmac('sha256', substr($ciphertext, 48).substr($ciphertext, 0, 16), hash('sha256', $password, true), true), substr($ciphertext, 16, 32))) return null;
return openssl_decrypt(substr($ciphertext, 48), "AES-256-CBC", hash('sha256', $password, true), OPENSSL_RAW_DATA, substr($ciphertext, 0, 16));
}
Usage:
$enc = encryptString("mysecretText", "myPassword");
$dec = decryptString($enc, "myPassword");
EDIT: This is a new version of functions that use AES256 GCM and PBKDF2 as key derivation, more secure.
function str_encryptaesgcm($plaintext, $password, $encoding = null) {
if ($plaintext != null && $password != null) {
$keysalt = openssl_random_pseudo_bytes(16);
$key = hash_pbkdf2("sha512", $password, $keysalt, 20000, 32, true);
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length("aes-256-gcm"));
$tag = "";
$encryptedstring = openssl_encrypt($plaintext, "aes-256-gcm", $key, OPENSSL_RAW_DATA, $iv, $tag, "", 16);
return $encoding == "hex" ? bin2hex($keysalt.$iv.$encryptedstring.$tag) : ($encoding == "base64" ? base64_encode($keysalt.$iv.$encryptedstring.$tag) : $keysalt.$iv.$encryptedstring.$tag);
}
}
function str_decryptaesgcm($encryptedstring, $password, $encoding = null) {
if ($encryptedstring != null && $password != null) {
$encryptedstring = $encoding == "hex" ? hex2bin($encryptedstring) : ($encoding == "base64" ? base64_decode($encryptedstring) : $encryptedstring);
$keysalt = substr($encryptedstring, 0, 16);
$key = hash_pbkdf2("sha512", $password, $keysalt, 20000, 32, true);
$ivlength = openssl_cipher_iv_length("aes-256-gcm");
$iv = substr($encryptedstring, 16, $ivlength);
$tag = substr($encryptedstring, -16);
return openssl_decrypt(substr($encryptedstring, 16 + $ivlength, -16), "aes-256-gcm", $key, OPENSSL_RAW_DATA, $iv, $tag);
}
}
Usage:
$enc = str_encryptaesgcm("mysecretText", "myPassword", "base64"); // return a base64 encrypted string, you can also choose hex or null as encoding.
$dec = str_decryptaesgcm($enc, "myPassword", "base64");
Historical Note: This was written at the time of PHP4. This is what we call "legacy code" now.
I have left this answer for historical purposes - but some of the methods are now deprecated, DES encryption method is not a recommended practice, etc.
I have not updated this code for two reasons: 1) I no longer work with encryption methods by hand in PHP, and 2) this code still serves the purpose it was intended for: to demonstrate the minimum, simplistic concept of how encryption can work in PHP.
If you find a similarly simplistic, "PHP encryption for dummies" kind of source that can get people started in 10-20 lines of code or less, let me know in comments.
Beyond that, please enjoy this Classic Episode of early-era PHP4 minimalistic encryption answer.
Ideally you have - or can get - access to the mcrypt PHP library, as its certainly popular and very useful a variety of tasks. Here's a run down of the different kinds of encryption and some example code: Encryption Techniques in PHP
//Listing 3: Encrypting Data Using the mcrypt_ecb Function
<?php
echo("<h3> Symmetric Encryption </h3>");
$key_value = "KEYVALUE";
$plain_text = "PLAINTEXT";
$encrypted_text = mcrypt_ecb(MCRYPT_DES, $key_value, $plain_text, MCRYPT_ENCRYPT);
echo ("<p><b> Text after encryption : </b>");
echo ( $encrypted_text );
$decrypted_text = mcrypt_ecb(MCRYPT_DES, $key_value, $encrypted_text, MCRYPT_DECRYPT);
echo ("<p><b> Text after decryption : </b>");
echo ( $decrypted_text );
?>
A few warnings:
1) Never use reversible, or "symmetric" encryption when a one-way hash will do.
2) If the data is truly sensitive, like credit card or social security numbers, stop; you need more than any simple chunk of code will provide, but rather you need a crypto library designed for this purpose and a significant amount of time to research the methods necessary. Further, the software crypto is probably <10% of security of sensitive data. It's like rewiring a nuclear power station - accept that the task is dangerous and difficult and beyond your knowledge if that's the case. The financial penalties can be immense, so better to use a service and ship responsibility to them.
3) Any sort of easily implementable encryption, as listed here, can reasonably protect mildly important information that you want to keep from prying eyes or limit exposure in the case of accidental/intentional leak. But seeing as how the key is stored in plain text on the web server, if they can get the data they can get the decryption key.
Be that as it may, have fun :)
In PHP, Encryption and Decryption of a string is possible using one of the Cryptography Extensions called OpenSSL function for encrypt and decrypt.
openssl_encrypt() Function: The openssl_encrypt() function is used to encrypt the data.
Syntax is as follows :
string openssl_encrypt( string $data, string $method, string $key, $options = 0, string $iv, string $tag= NULL, string $aad, int $tag_length = 16 )
Parameters are as follows :
$data: It holds the string or data which need to be encrypted.
$method: The cipher method is adopted using openssl_get_cipher_methods() function.
$key: It holds the encryption key.
$options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
$iv: It holds the initialization vector which is not NULL.
$tag: It holds the authentication tag which is passed by reference when using AEAD cipher mode (GCM or CCM).
$aad: It holds the additional authentication data.
$tag_length: It holds the length of the authentication tag. The length of authentication tag lies between 4 to 16 for GCM mode.
Return Value: It returns the encrypted string on success or FALSE on failure.
openssl_decrypt() Function The openssl_decrypt() function is used to decrypt the data.
Syntax is as follows :
string openssl_decrypt( string $data, string $method, string $key, int $options = 0, string $iv, string $tag, string $aad)
Parameters are as follows :
$data: It holds the string or data which need to be encrypted.
$method: The cipher method is adopted using openssl_get_cipher_methods() function.
$key: It holds the encryption key.
$options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
$iv: It holds the initialization vector which is not NULL.
$tag: It holds the authentication tag using AEAD cipher mode (GCM or CCM). When authentication fails openssl_decrypt() returns FALSE.
$aad: It holds the additional authentication data.
Return Value: It returns the decrypted string on success or FALSE on failure.
Approach: First declare a string and store it into variable and use openssl_encrypt() function to encrypt the given string and use openssl_decrypt() function to descrypt the given string.
You can find the examples at : https://www.geeksforgeeks.org/how-to-encrypt-and-decrypt-a-php-string/
Below code work in php for all string with special character
// Encrypt text --
$token = "9611222007552";
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$enc_iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($cipher_method));
$crypted_token = openssl_encrypt($token, $cipher_method, $enc_key, 0, $enc_iv) . "::" . bin2hex($enc_iv);
echo $crypted_token;
//unset($token, $cipher_method, $enc_key, $enc_iv);
// Decrypt text --
list($crypted_token, $enc_iv) = explode("::", $crypted_token);
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$token = openssl_decrypt($crypted_token, $cipher_method, $enc_key, 0, hex2bin($enc_iv));
echo $token;
//unset($crypted_token, $cipher_method, $enc_key, $enc_iv);
What I mean is:
Original String + Salt or Key --> Encrypted String
Encrypted String + Salt or Key --> Decrypted (Original String)
Maybe something like:
"hello world!" + "ABCD1234" --> Encrypt --> "2a2ffa8f13220befbe30819047e23b2c" (may be, for e.g)
"2a2ffa8f13220befbe30819047e23b2c" --> Decrypt with "ABCD1234" --> "hello world!"
In PHP, how can you do this?
Attempted to use Crypt_Blowfish, but it didn't work for me.
Before you do anything further, seek to understand the difference between encryption and authentication, and why you probably want authenticated encryption rather than just encryption.
To implement authenticated encryption, you want to Encrypt then MAC. The order of encryption and authentication is very important! One of the existing answers to this question made this mistake; as do many cryptography libraries written in PHP.
You should avoid implementing your own cryptography, and instead use a secure library written by and reviewed by cryptography experts.
Update: PHP 7.2 now provides libsodium! For best security, update your systems to use PHP 7.2 or higher and only follow the libsodium advice in this answer.
Use libsodium if you have PECL access (or sodium_compat if you want libsodium without PECL); otherwise...
Use defuse/php-encryption; don't roll your own cryptography!
Both of the libraries linked above make it easy and painless to implement authenticated encryption into your own libraries.
If you still want to write and deploy your own cryptography library, against the conventional wisdom of every cryptography expert on the Internet, these are the steps you would have to take.
Encryption:
Encrypt using AES in CTR mode. You may also use GCM (which removes the need for a separate MAC). Additionally, ChaCha20 and Salsa20 (provided by libsodium) are stream ciphers and do not need special modes.
Unless you chose GCM above, you should authenticate the ciphertext with HMAC-SHA-256 (or, for the stream ciphers, Poly1305 -- most libsodium APIs do this for you). The MAC should cover the IV as well as the ciphertext!
Decryption:
Unless Poly1305 or GCM is used, recalculate the MAC of the ciphertext and compare it with the MAC that was sent using hash_equals(). If it fails, abort.
Decrypt the message.
Other Design Considerations:
Do not compress anything ever. Ciphertext is not compressible; compressing plaintext before encryption can lead to information leaks (e.g. CRIME and BREACH on TLS).
Make sure you use mb_strlen() and mb_substr(), using the '8bit' character set mode to prevent mbstring.func_overload issues.
IVs should be generating using a CSPRNG; If you're using mcrypt_create_iv(), DO NOT USE MCRYPT_RAND!
Also check out random_compat.
Unless you're using an AEAD construct, ALWAYS encrypt then MAC!
bin2hex(), base64_encode(), etc. may leak information about your encryption keys via cache timing. Avoid them if possible.
Even if you follow the advice given here, a lot can go wrong with cryptography. Always have a cryptography expert review your implementation. If you are not fortunate enough to be personal friends with a cryptography student at your local university, you can always try the Cryptography Stack Exchange forum for advice.
If you need a professional analysis of your implementation, you can always hire a reputable team of security consultants to review your PHP cryptography code (disclosure: my employer).
Important: When to Not Use Encryption
Don't encrypt passwords. You want to hash them instead, using one of these password-hashing algorithms:
Argon2
scrypt
bcrypt
PBKDF2-SHA256 with 86,000 iterations
Never use a general-purpose hash function (MD5, SHA256) for password storage.
Don't encrypt URL Parameters. It's the wrong tool for the job.
PHP String Encryption Example with Libsodium
If you are on PHP < 7.2 or otherwise do not have libsodium installed, you can use sodium_compat to accomplish the same result (albeit slower).
<?php
declare(strict_types=1);
/**
* Encrypt a message
*
* #param string $message - message to encrypt
* #param string $key - encryption key
* #return string
* #throws RangeException
*/
function safeEncrypt(string $message, string $key): string
{
if (mb_strlen($key, '8bit') !== SODIUM_CRYPTO_SECRETBOX_KEYBYTES) {
throw new RangeException('Key is not the correct size (must be 32 bytes).');
}
$nonce = random_bytes(SODIUM_CRYPTO_SECRETBOX_NONCEBYTES);
$cipher = base64_encode(
$nonce.
sodium_crypto_secretbox(
$message,
$nonce,
$key
)
);
sodium_memzero($message);
sodium_memzero($key);
return $cipher;
}
/**
* Decrypt a message
*
* #param string $encrypted - message encrypted with safeEncrypt()
* #param string $key - encryption key
* #return string
* #throws Exception
*/
function safeDecrypt(string $encrypted, string $key): string
{
$decoded = base64_decode($encrypted);
$nonce = mb_substr($decoded, 0, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, '8bit');
$ciphertext = mb_substr($decoded, SODIUM_CRYPTO_SECRETBOX_NONCEBYTES, null, '8bit');
$plain = sodium_crypto_secretbox_open(
$ciphertext,
$nonce,
$key
);
if (!is_string($plain)) {
throw new Exception('Invalid MAC');
}
sodium_memzero($ciphertext);
sodium_memzero($key);
return $plain;
}
Then to test it out:
<?php
// This refers to the previous code block.
require "safeCrypto.php";
// Do this once then store it somehow:
$key = random_bytes(SODIUM_CRYPTO_SECRETBOX_KEYBYTES);
$message = 'We are all living in a yellow submarine';
$ciphertext = safeEncrypt($message, $key);
$plaintext = safeDecrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
Halite - Libsodium Made Easier
One of the projects I've been working on is an encryption library called Halite, which aims to make libsodium easier and more intuitive.
<?php
use \ParagonIE\Halite\KeyFactory;
use \ParagonIE\Halite\Symmetric\Crypto as SymmetricCrypto;
// Generate a new random symmetric-key encryption key. You're going to want to store this:
$key = new KeyFactory::generateEncryptionKey();
// To save your encryption key:
KeyFactory::save($key, '/path/to/secret.key');
// To load it again:
$loadedkey = KeyFactory::loadEncryptionKey('/path/to/secret.key');
$message = 'We are all living in a yellow submarine';
$ciphertext = SymmetricCrypto::encrypt($message, $key);
$plaintext = SymmetricCrypto::decrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
All of the underlying cryptography is handled by libsodium.
Example with defuse/php-encryption
<?php
/**
* This requires https://github.com/defuse/php-encryption
* php composer.phar require defuse/php-encryption
*/
use Defuse\Crypto\Crypto;
use Defuse\Crypto\Key;
require "vendor/autoload.php";
// Do this once then store it somehow:
$key = Key::createNewRandomKey();
$message = 'We are all living in a yellow submarine';
$ciphertext = Crypto::encrypt($message, $key);
$plaintext = Crypto::decrypt($ciphertext, $key);
var_dump($ciphertext);
var_dump($plaintext);
Note: Crypto::encrypt() returns hex-encoded output.
Encryption Key Management
If you're tempted to use a "password", stop right now. You need a random 128-bit encryption key, not a human memorable password.
You can store an encryption key for long-term use like so:
$storeMe = bin2hex($key);
And, on demand, you can retrieve it like so:
$key = hex2bin($storeMe);
I strongly recommend just storing a randomly generated key for long-term use instead of any sort of password as the key (or to derive the key).
If you're using Defuse's library:
$string = $keyObject->saveToAsciiSafeString()
$loaded = Key::loadFromAsciiSafeString($string);
"But I really want to use a password."
That's a bad idea, but okay, here's how to do it safely.
First, generate a random key and store it in a constant.
/**
* Replace this with your own salt!
* Use bin2hex() then add \x before every 2 hex characters, like so:
*/
define('MY_PBKDF2_SALT', "\x2d\xb7\x68\x1a\x28\x15\xbe\x06\x33\xa0\x7e\x0e\x8f\x79\xd5\xdf");
Note that you're adding extra work and could just use this constant as the key and save yourself a lot of heartache!
Then use PBKDF2 (like so) to derive a suitable encryption key from your password rather than encrypting with your password directly.
/**
* Get an AES key from a static password and a secret salt
*
* #param string $password Your weak password here
* #param int $keysize Number of bytes in encryption key
*/
function getKeyFromPassword($password, $keysize = 16)
{
return hash_pbkdf2(
'sha256',
$password,
MY_PBKDF2_SALT,
100000, // Number of iterations
$keysize,
true
);
}
Don't just use a 16-character password. Your encryption key will be comically broken.
I'm late to the party, but searching for the correct way to do it I came across this page it was one of the top Google search returns, so I will like to share my view on the problem, which I consider it to be up to date at the time of writing this post (beginning of 2017). From PHP 7.1.0 the mcrypt_decrypt and mcrypt_encrypt is going to be deprecated, so building future proof code should use openssl_encrypt and openssl_decrypt
You can do something like:
$string_to_encrypt="Test";
$password="password";
$encrypted_string=openssl_encrypt($string_to_encrypt,"AES-128-ECB",$password);
$decrypted_string=openssl_decrypt($encrypted_string,"AES-128-ECB",$password);
Important: This uses ECB mode, which isn't secure. If you want a simple solution without taking a crash course in cryptography engineering, don't write it yourself, just use a library.
You can use any other chipper methods as well, depending on your security need. To find out the available chipper methods please see the openssl_get_cipher_methods function.
What not to do
WARNING:
This answer uses ECB. ECB is not an encryption mode, it's only a building block. Using ECB as demonstrated in this answer does not actually encrypt the string securely. Do not use ECB in your code. See Scott's answer for a good solution.
I got it on myself. Actually i found some answer on google and just modified something. The result is completely insecure however.
<?php
define("ENCRYPTION_KEY", "!##$%^&*");
$string = "This is the original data string!";
echo $encrypted = encrypt($string, ENCRYPTION_KEY);
echo "<br />";
echo $decrypted = decrypt($encrypted, ENCRYPTION_KEY);
/**
* Returns an encrypted & utf8-encoded
*/
function encrypt($pure_string, $encryption_key) {
$iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$encrypted_string = mcrypt_encrypt(MCRYPT_BLOWFISH, $encryption_key, utf8_encode($pure_string), MCRYPT_MODE_ECB, $iv);
return $encrypted_string;
}
/**
* Returns decrypted original string
*/
function decrypt($encrypted_string, $encryption_key) {
$iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$decrypted_string = mcrypt_decrypt(MCRYPT_BLOWFISH, $encryption_key, $encrypted_string, MCRYPT_MODE_ECB, $iv);
return $decrypted_string;
}
?>
For Laravel framework
If you are using Laravel framework then it's more easy to encrypt and decrypt with internal functions.
$string = 'Some text to be encrypted';
$encrypted = \Illuminate\Support\Facades\Crypt::encrypt($string);
$decrypted_string = \Illuminate\Support\Facades\Crypt::decrypt($encrypted);
var_dump($string);
var_dump($encrypted);
var_dump($decrypted_string);
Note: Be sure to set a 16, 24, or 32 character random string in the
key option of the config/app.php file. Otherwise, encrypted values
will not be secure.
Updated
PHP 7 ready version. It uses openssl_encrypt function from PHP OpenSSL Library.
class Openssl_EncryptDecrypt {
function encrypt ($pure_string, $encryption_key) {
$cipher = 'AES-256-CBC';
$options = OPENSSL_RAW_DATA;
$hash_algo = 'sha256';
$sha2len = 32;
$ivlen = openssl_cipher_iv_length($cipher);
$iv = openssl_random_pseudo_bytes($ivlen);
$ciphertext_raw = openssl_encrypt($pure_string, $cipher, $encryption_key, $options, $iv);
$hmac = hash_hmac($hash_algo, $ciphertext_raw, $encryption_key, true);
return $iv.$hmac.$ciphertext_raw;
}
function decrypt ($encrypted_string, $encryption_key) {
$cipher = 'AES-256-CBC';
$options = OPENSSL_RAW_DATA;
$hash_algo = 'sha256';
$sha2len = 32;
$ivlen = openssl_cipher_iv_length($cipher);
$iv = substr($encrypted_string, 0, $ivlen);
$hmac = substr($encrypted_string, $ivlen, $sha2len);
$ciphertext_raw = substr($encrypted_string, $ivlen+$sha2len);
$original_plaintext = openssl_decrypt($ciphertext_raw, $cipher, $encryption_key, $options, $iv);
$calcmac = hash_hmac($hash_algo, $ciphertext_raw, $encryption_key, true);
if(function_exists('hash_equals')) {
if (hash_equals($hmac, $calcmac)) return $original_plaintext;
} else {
if ($this->hash_equals_custom($hmac, $calcmac)) return $original_plaintext;
}
}
/**
* (Optional)
* hash_equals() function polyfilling.
* PHP 5.6+ timing attack safe comparison
*/
function hash_equals_custom($knownString, $userString) {
if (function_exists('mb_strlen')) {
$kLen = mb_strlen($knownString, '8bit');
$uLen = mb_strlen($userString, '8bit');
} else {
$kLen = strlen($knownString);
$uLen = strlen($userString);
}
if ($kLen !== $uLen) {
return false;
}
$result = 0;
for ($i = 0; $i < $kLen; $i++) {
$result |= (ord($knownString[$i]) ^ ord($userString[$i]));
}
return 0 === $result;
}
}
define('ENCRYPTION_KEY', '__^%&Q#$&*!##$%^&*^__');
$string = "This is the original string!";
$OpensslEncryption = new Openssl_EncryptDecrypt;
$encrypted = $OpensslEncryption->encrypt($string, ENCRYPTION_KEY);
$decrypted = $OpensslEncryption->decrypt($encrypted, ENCRYPTION_KEY);
If you don't want to use library (which you should) then use something like this (PHP 7):
function sign($message, $key) {
return hash_hmac('sha256', $message, $key) . $message;
}
function verify($bundle, $key) {
return hash_equals(
hash_hmac('sha256', mb_substr($bundle, 64, null, '8bit'), $key),
mb_substr($bundle, 0, 64, '8bit')
);
}
function getKey($password, $keysize = 16) {
return hash_pbkdf2('sha256',$password,'some_token',100000,$keysize,true);
}
function encrypt($message, $password) {
$iv = random_bytes(16);
$key = getKey($password);
$result = sign(openssl_encrypt($message,'aes-256-ctr',$key,OPENSSL_RAW_DATA,$iv), $key);
return bin2hex($iv).bin2hex($result);
}
function decrypt($hash, $password) {
$iv = hex2bin(substr($hash, 0, 32));
$data = hex2bin(substr($hash, 32));
$key = getKey($password);
if (!verify($data, $key)) {
return null;
}
return openssl_decrypt(mb_substr($data, 64, null, '8bit'),'aes-256-ctr',$key,OPENSSL_RAW_DATA,$iv);
}
$string_to_encrypt='John Smith';
$password='password';
$encrypted_string=encrypt($string_to_encrypt, $password);
$decrypted_string=decrypt($encrypted_string, $password);
These are compact methods to encrypt / decrypt strings with PHP using AES256 CBC:
function encryptString($plaintext, $password, $encoding = null) {
$iv = openssl_random_pseudo_bytes(16);
$ciphertext = openssl_encrypt($plaintext, "AES-256-CBC", hash('sha256', $password, true), OPENSSL_RAW_DATA, $iv);
$hmac = hash_hmac('sha256', $ciphertext.$iv, hash('sha256', $password, true), true);
return $encoding == "hex" ? bin2hex($iv.$hmac.$ciphertext) : ($encoding == "base64" ? base64_encode($iv.$hmac.$ciphertext) : $iv.$hmac.$ciphertext);
}
function decryptString($ciphertext, $password, $encoding = null) {
$ciphertext = $encoding == "hex" ? hex2bin($ciphertext) : ($encoding == "base64" ? base64_decode($ciphertext) : $ciphertext);
if (!hash_equals(hash_hmac('sha256', substr($ciphertext, 48).substr($ciphertext, 0, 16), hash('sha256', $password, true), true), substr($ciphertext, 16, 32))) return null;
return openssl_decrypt(substr($ciphertext, 48), "AES-256-CBC", hash('sha256', $password, true), OPENSSL_RAW_DATA, substr($ciphertext, 0, 16));
}
Usage:
$enc = encryptString("mysecretText", "myPassword");
$dec = decryptString($enc, "myPassword");
EDIT: This is a new version of functions that use AES256 GCM and PBKDF2 as key derivation, more secure.
function str_encryptaesgcm($plaintext, $password, $encoding = null) {
if ($plaintext != null && $password != null) {
$keysalt = openssl_random_pseudo_bytes(16);
$key = hash_pbkdf2("sha512", $password, $keysalt, 20000, 32, true);
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length("aes-256-gcm"));
$tag = "";
$encryptedstring = openssl_encrypt($plaintext, "aes-256-gcm", $key, OPENSSL_RAW_DATA, $iv, $tag, "", 16);
return $encoding == "hex" ? bin2hex($keysalt.$iv.$encryptedstring.$tag) : ($encoding == "base64" ? base64_encode($keysalt.$iv.$encryptedstring.$tag) : $keysalt.$iv.$encryptedstring.$tag);
}
}
function str_decryptaesgcm($encryptedstring, $password, $encoding = null) {
if ($encryptedstring != null && $password != null) {
$encryptedstring = $encoding == "hex" ? hex2bin($encryptedstring) : ($encoding == "base64" ? base64_decode($encryptedstring) : $encryptedstring);
$keysalt = substr($encryptedstring, 0, 16);
$key = hash_pbkdf2("sha512", $password, $keysalt, 20000, 32, true);
$ivlength = openssl_cipher_iv_length("aes-256-gcm");
$iv = substr($encryptedstring, 16, $ivlength);
$tag = substr($encryptedstring, -16);
return openssl_decrypt(substr($encryptedstring, 16 + $ivlength, -16), "aes-256-gcm", $key, OPENSSL_RAW_DATA, $iv, $tag);
}
}
Usage:
$enc = str_encryptaesgcm("mysecretText", "myPassword", "base64"); // return a base64 encrypted string, you can also choose hex or null as encoding.
$dec = str_decryptaesgcm($enc, "myPassword", "base64");
Historical Note: This was written at the time of PHP4. This is what we call "legacy code" now.
I have left this answer for historical purposes - but some of the methods are now deprecated, DES encryption method is not a recommended practice, etc.
I have not updated this code for two reasons: 1) I no longer work with encryption methods by hand in PHP, and 2) this code still serves the purpose it was intended for: to demonstrate the minimum, simplistic concept of how encryption can work in PHP.
If you find a similarly simplistic, "PHP encryption for dummies" kind of source that can get people started in 10-20 lines of code or less, let me know in comments.
Beyond that, please enjoy this Classic Episode of early-era PHP4 minimalistic encryption answer.
Ideally you have - or can get - access to the mcrypt PHP library, as its certainly popular and very useful a variety of tasks. Here's a run down of the different kinds of encryption and some example code: Encryption Techniques in PHP
//Listing 3: Encrypting Data Using the mcrypt_ecb Function
<?php
echo("<h3> Symmetric Encryption </h3>");
$key_value = "KEYVALUE";
$plain_text = "PLAINTEXT";
$encrypted_text = mcrypt_ecb(MCRYPT_DES, $key_value, $plain_text, MCRYPT_ENCRYPT);
echo ("<p><b> Text after encryption : </b>");
echo ( $encrypted_text );
$decrypted_text = mcrypt_ecb(MCRYPT_DES, $key_value, $encrypted_text, MCRYPT_DECRYPT);
echo ("<p><b> Text after decryption : </b>");
echo ( $decrypted_text );
?>
A few warnings:
1) Never use reversible, or "symmetric" encryption when a one-way hash will do.
2) If the data is truly sensitive, like credit card or social security numbers, stop; you need more than any simple chunk of code will provide, but rather you need a crypto library designed for this purpose and a significant amount of time to research the methods necessary. Further, the software crypto is probably <10% of security of sensitive data. It's like rewiring a nuclear power station - accept that the task is dangerous and difficult and beyond your knowledge if that's the case. The financial penalties can be immense, so better to use a service and ship responsibility to them.
3) Any sort of easily implementable encryption, as listed here, can reasonably protect mildly important information that you want to keep from prying eyes or limit exposure in the case of accidental/intentional leak. But seeing as how the key is stored in plain text on the web server, if they can get the data they can get the decryption key.
Be that as it may, have fun :)
In PHP, Encryption and Decryption of a string is possible using one of the Cryptography Extensions called OpenSSL function for encrypt and decrypt.
openssl_encrypt() Function: The openssl_encrypt() function is used to encrypt the data.
Syntax is as follows :
string openssl_encrypt( string $data, string $method, string $key, $options = 0, string $iv, string $tag= NULL, string $aad, int $tag_length = 16 )
Parameters are as follows :
$data: It holds the string or data which need to be encrypted.
$method: The cipher method is adopted using openssl_get_cipher_methods() function.
$key: It holds the encryption key.
$options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
$iv: It holds the initialization vector which is not NULL.
$tag: It holds the authentication tag which is passed by reference when using AEAD cipher mode (GCM or CCM).
$aad: It holds the additional authentication data.
$tag_length: It holds the length of the authentication tag. The length of authentication tag lies between 4 to 16 for GCM mode.
Return Value: It returns the encrypted string on success or FALSE on failure.
openssl_decrypt() Function The openssl_decrypt() function is used to decrypt the data.
Syntax is as follows :
string openssl_decrypt( string $data, string $method, string $key, int $options = 0, string $iv, string $tag, string $aad)
Parameters are as follows :
$data: It holds the string or data which need to be encrypted.
$method: The cipher method is adopted using openssl_get_cipher_methods() function.
$key: It holds the encryption key.
$options: It holds the bitwise disjunction of the flags OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING.
$iv: It holds the initialization vector which is not NULL.
$tag: It holds the authentication tag using AEAD cipher mode (GCM or CCM). When authentication fails openssl_decrypt() returns FALSE.
$aad: It holds the additional authentication data.
Return Value: It returns the decrypted string on success or FALSE on failure.
Approach: First declare a string and store it into variable and use openssl_encrypt() function to encrypt the given string and use openssl_decrypt() function to descrypt the given string.
You can find the examples at : https://www.geeksforgeeks.org/how-to-encrypt-and-decrypt-a-php-string/
Below code work in php for all string with special character
// Encrypt text --
$token = "9611222007552";
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$enc_iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($cipher_method));
$crypted_token = openssl_encrypt($token, $cipher_method, $enc_key, 0, $enc_iv) . "::" . bin2hex($enc_iv);
echo $crypted_token;
//unset($token, $cipher_method, $enc_key, $enc_iv);
// Decrypt text --
list($crypted_token, $enc_iv) = explode("::", $crypted_token);
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$token = openssl_decrypt($crypted_token, $cipher_method, $enc_key, 0, hex2bin($enc_iv));
echo $token;
//unset($crypted_token, $cipher_method, $enc_key, $enc_iv);