Simplest two-way encryption using PHP

Question

What is the simplest way of doing two way encryption in common PHP installs?

I need to be able to encrypt data with a string key, and use the same key to decrypt on

Answer 1

IMPORTANT this answer is valid only for PHP 5, in PHP 7 use built-in cryptographic functions.

Here is simple but secure enough implementation:

• AES-256 encryption in CBC mode
• PBKDF2 to create encryption key out of plain-text password
• HMAC to authenticate the encrypted message.

Code and examples are here: https://stackoverflow.com/a/19445173/1387163