This content originally appeared on DEV Community and was authored by ManuTheCoder
Have you ever wanted to improve your app's security by hiding everything in your database? Let's make a simple encryption and decryption script in PHP using the openssl_encrypt and openssl_decrypt functions
Step 1
Let's define some variables
<?php
define("encryption_method", "AES-128-CBC");
define("key", "your_amazing_key_here");
Obviously, change the encryption key
Step 2
Creating a function to encrypt data
<?php
function encrypt($data) {
$key = key;
$plaintext = $data;
$ivlen = openssl_cipher_iv_length($cipher = encryption_method);
$iv = openssl_random_pseudo_bytes($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);
return $ciphertext;
}
Explained
-
openssl_random_pseudo_bytes- Generates a string of pseudo-random bytes, with the number of bytes determined by the length parameter. -
openssl_cipher_iv_length- The cipher method, see openssl_get_cipher_methods() for a list of potential values -
openssl_encrypt- PHP lacks a build-in function to encrypt and decrypt large files.openssl_encrypt()can be used to encrypt strings -
hash_hmac- Returns a string containing the calculated message digest as lowercase hexits unless binary is set to true in which case the raw binary representation -
base64_encode- Encodes the given string with base64
Step 3
Let's create a simple script to decrypt our encrypted string
function decrypt($data) {
$key = key;
$c = base64_decode($data);
$ivlen = openssl_cipher_iv_length($cipher = encryption_method);
$iv = substr($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))
{
return $original_plaintext;
}
}
Explained
The only difference here is the openssl_decrypt function. Takes a raw or base64 encoded string and decrypts it using a given method and key.
Complete code
<?php
define("encryption_method", "AES-128-CBC");
define("key", "your_amazing_key_here");
function encrypt($data) {
$key = key;
$plaintext = $data;
$ivlen = openssl_cipher_iv_length($cipher = encryption_method);
$iv = openssl_random_pseudo_bytes($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);
return $ciphertext;
}
function decrypt($data) {
$key = key;
$c = base64_decode($data);
$ivlen = openssl_cipher_iv_length($cipher = encryption_method);
$iv = substr($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))
{
return $original_plaintext;
}
}
echo encrypt("Hello World!");
echo "\n";
echo decrypt(encrypt("Hello World!"));
?>
How to use
To encrypt something
encrypt("Foo");
To decrypt something
decrypt("lF0wxjGE4H7bbSH/51+ihseCa7aT5hn2Wm0b4expCxqc/W9A38m37QXakG/i/hAjSrNzMpINfZWnh8/9Kd2nodHTiP0Vq0euQ4Z3BOO1vt0WP6dsGRR03po7e4dIlep/lMrwS341jzN+o+FPUtcPVPUr6BEc0RtHwFoUH6NNm+2mWXYLUVH4Ct86iuD8+6eBC1SG3IG21R1dWREGdLrsWQ==")
See if you can decrypt the following message. I'll post the encryption key in the comments section later!
Hint: The key is a 3-letter programming language
Credits
This code was taken from my own app, Smartlist. Smartlist is a home inventory app that lets you keep track of what's in your home! We encrypt our items, tasks, and notes too!
This content originally appeared on DEV Community and was authored by ManuTheCoder
ManuTheCoder | Sciencx (2021-11-20T07:03:52+00:00) Really simple encryption in PHP!. Retrieved from https://www.scien.cx/2021/11/20/really-simple-encryption-in-php/
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