<?php
    $key = "mySecretKey";
    $cipher = "aes-128-gcm";
    $ivlen = openssl_cipher_iv_length($cipher);

    $iv = openssl_random_pseudo_bytes($ivlen);
    $ciphertext = openssl_encrypt("message to be encrypted", $cipher, $key,     $options=0, $iv, $tag);

    $original_plaintext = openssl_decrypt($ciphertext, $cipher, $key, 0, $iv, $tag);

    echo "original message: ".$original_plaintext."n";

    // $iv and $tag change each time we encrypt the data, so store these
?>