Php implementation of encryption and decryption using openssl_encrypt and openssl_decrypt

php-openssl-crypto.php

<?php
    $ENCRYPTION_KEY = '';
    $ENCRYPTION_ALGORITHM = 'AES-128-ECB';

    function encrypt($plainText) {
        global $ENCRYPTION_KEY;
        global $ENCRYPTION_ALGORITHM;
        $EncryptionKey = makeHash($ENCRYPTION_KEY, 16);

        $encryptedText = openssl_encrypt($plainText, $ENCRYPTION_ALGORITHM, $EncryptionKey);

        return $encryptedText;
    }

    function decrypt($ciphertext) {
        global $ENCRYPTION_KEY;
        global $ENCRYPTION_ALGORITHM;
        $EncryptionKey = makeHash($ENCRYPTION_KEY, 16);

        $decrypt = openssl_decrypt($ciphertext, $ENCRYPTION_ALGORITHM, $EncryptionKey);

        return $decrypt;
    }

    function makeHash($text, $length) {
        $hash_key = hash("sha512", $text, false);
        return substr($hash_key,0,$length);
    }

    // $ct = encrypt("hello");
    // echo $ct."\n";
    // echo decrypt($ct)."\n";
?>