How to encrypt and decrypt data in php? - php

Question

How to encrypt and decrypt data in php?
My code so far is:-
function encrypter($plaintext)
{
$plaintext = strtolower($plaintext);
$crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256,FLENCKEY,$plaintext,MCRYPT_MODE_ECB);
return trim(base64_encode($crypttext));
}
function decrypter($crypttext)
{
$crypttext = base64_decode($crypttext);
$plaintext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256,FLENCKEY,$crypttext,MCRYPT_MODE_ECB);
return trim($crypttext);
}
$test = "abc#gmail.com";
echo encrypter(test);
Output is
iLmUJHKPjPmA9vY0jfQ51qGpLPWC/5bTYWFDOj7Hr08=
echo decrypter(test);
Output is
��-

Answer 1

In your decrypter() function, you return the wrong data.
You should return $plaintext instead of $crypttext:
function decrypter($crypttext)
{
$crypttext = base64_decode($crypttext);
$plaintext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256,FLENCKEY,$crypttext,MCRYPT_MODE_ECB);
//return trim($crypttext);
return trim($plaintext);
}

Answer 2

The other code samples on this page (including the question) are not secure.
To be secure:
Don't use mcrypt.
Use authenticated encryption.
Never use ECB mode (a.k.a. MCRYPT_MODE_ECB).
See this answer for secure encryption in PHP.

Answer 3

This is what I use. Super simple.
function encrypt_decrypt($action, $string) {
$output = false;
$key = '$b#bl2I#?%%4K*mC6r273~8l3|6#>D';
$iv = md5(md5($key));
if( $action == 'encrypt' ) {
$output = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), $string, MCRYPT_MODE_CBC, $iv);
$output = base64_encode($output);
}
else if( $action == 'decrypt' ){
$output = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode($string), MCRYPT_MODE_CBC, $iv);
$output = rtrim($output, "");
}
return $output;
}
You can change $key to whatever you want, or leave it. (this is not my key, btw)
encrypt_decrypt('encrypt', $str) to encrypt
encrypt_decrypt('decrypt', $str) to decrypt

Answer 4

Inside the decrypter function, change the
return trim($crypttext);
to
return trim($plaintext);
But looking at your function, I am not quite sure whether it will return exactly the same string, because of the strtolower function. You can't just do a strtoupper function as the original text may not be all in capital letters.

Answer 5

Warning
mcrypt_encrypt has been DEPRECATED as of PHP 7.1.0. Relying on this function is highly discouraged.
Use openssl_encrypt instead.