How to create two way encode/decode methods using use-specific key - PHP?

Question

I need two functions/methods, one to encode, one to decode. This is not for storing passwords. Each user will have a specific key/salt to encode th

Answer 1

$myVarIWantToEncodeAndDecode

Define key (salt, broth etc..): $key = "#&$sdfdfs789fs7d";

To encode:

$encoded = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), $myVarIWantToEncodeAndDecode, MCRYPT_MODE_CBC, md5(md5($key))));

To decode:

$decoded = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode($encoded), MCRYPT_MODE_CBC, md5(md5($key))), "\0");

Note: mcrypt_decrypt has been DEPRECATED as of PHP 7.1.0. Relying on this function is highly discouraged.