php-aes-gcm

A compact and foolproof AES-256 GCM implementation for PHP.

Install

To take advantage of security features in PHP 8.2+, install from the main branch.

composer require mmeyer2k/php-aes-gcm

If you need to support PHP versions prior to 8.2, install from the legacy branch.

composer require "mmeyer2k/php-aes-gcm:dev-legacy"

Encrypted data is cross-compatible between the two branches. The only differences are the presence of #\SensitiveParamter in the function signatures and usage of named parameters for clarity.

Basic usage

use Mmeyer2k\AesGcm\AesGcm;

$msg = 'AAAAAAAA';
$key = 'BBBBBBBB';

$enc = AesGcm::encrypt($msg, $key);

$dec = AesGcm::decrypt($enc, $key);

Keys

For full security, 256-bit keys should be generated using a cryptographically secure random number generator.

In PHP

$key = random_bytes(32);

In the shell (with base64 encoding)

head -c 32 /dev/urandom | base64 -w 0 | xargs echo

In general, it is best to use some form of encoding when storing keys in a string format. This library expects all keys to be decoded before use.