ppnEncryption.php

<?php 
function ppnEncrypt( $data , $key )
{
    $method = 'aes-256-gcm';
    $key = base64_decode( $key );
    $iv = openssl_random_pseudo_bytes( openssl_cipher_iv_length( $method ) );
    $tag = ""; // openssl_encrypt will fill this
    $result = openssl_encrypt( $data , $method , $key , OPENSSL_RAW_DATA , $iv , $tag , "" , 16 );
    return base64_encode( $iv.$tag.$result );
}

function ppnDecrypt( $data , $key )
{
    $method = 'aes-256-gcm';
    $data = base64_decode( $data );
    $key = base64_decode( $key );
    $ivLength = openssl_cipher_iv_length( $method );
    $iv = substr( $data , 0 , $ivLength );
    $tag = substr( $data , $ivLength , 16 );
    $text = substr( $data , $ivLength+16 );
    return openssl_decrypt( $text , $method , $key , OPENSSL_RAW_DATA , $iv , $tag );
}
?>