README

A PHP library for JSON Web Encryption (JWE) as defined in RFC 7516.

Supports symmetric shared-key and asymmetric RSA end-to-end encryption, multiple content encryption algorithms, and both JWE Compact and JSON serialization formats.

Requirements

• PHP 7.4 or 8.0+
• ext-openssl
• ext-json

Installation

composer require silencenjoyer/jwe

Supported algorithms

Usage

Symmetric encryption (shared secret)

Both parties share the same secret key. The key is used directly as the Content Encryption Key (CEK), so encrypted_key in the JWE token is empty.

use Silencenjoyer\Jwe\Ciphers\Factory\Aes256GcmFactory;
use Silencenjoyer\Jwe\Decryptors\Decryptor;
use Silencenjoyer\Jwe\Encryptors\Encryptor;
use Silencenjoyer\Jwe\KeyEncapsulation\DirectKeyUnwrapper;
use Silencenjoyer\Jwe\KeyEncapsulation\DirectKeyWrapper;
use Silencenjoyer\Jwe\Keys\Key;
use Silencenjoyer\Jwe\Serializers\CompactSerializer;

// A 32-byte shared secret for A256GCM (use 64 bytes for A256CBC-HS512)
$sharedKey = Key::fromContent('a-32-byte-secret-key-goes-here!!');

$encryptor = new Encryptor(
    new DirectKeyWrapper($sharedKey),
    new Aes256GcmFactory(),
);

$decryptor = new Decryptor(
    new DirectKeyUnwrapper($sharedKey),
    new Aes256GcmFactory(),
);

$serializer = new CompactSerializer();

// Encrypt
$token     = $encryptor->encrypt('Hello, World!');
$compactJwe = $serializer->serialize($token);
// eyJhbGciOiJkaXIiLCJlbmMiOiJBMjU2R0NNIn0...<iv>.<ciphertext>.<tag>

// Decrypt
$plaintext = $decryptor->decrypt($serializer->unserialize($compactJwe));
// "Hello, World!"

RSA end-to-end encryption

The sender encrypts a random CEK with the recipient's public RSA key. Only the holder of the matching private key can recover the CEK and decrypt the content. No shared secret is required.

use Silencenjoyer\Jwe\Ciphers\Factory\Aes256GcmFactory;
use Silencenjoyer\Jwe\Decryptors\Decryptor;
use Silencenjoyer\Jwe\Encryptors\Encryptor;
use Silencenjoyer\Jwe\KeyEncapsulation\RsaKeyUnwrapper;
use Silencenjoyer\Jwe\KeyEncapsulation\RsaKeyWrapper;
use Silencenjoyer\Jwe\Keys\Key;
use Silencenjoyer\Jwe\Serializers\CompactSerializer;

$publicKey  = Key::fromPath('/path/to/public.pem');
$privateKey = Key::fromPath('/path/to/private.pem');

// Sender side: encrypt with recipient's public key
$encryptor = new Encryptor(
    new RsaKeyWrapper($publicKey),
    new Aes256GcmFactory(),
);

$serializer = new CompactSerializer();
$compactJwe  = $serializer->serialize($encryptor->encrypt('Secret message'));

// Recipient side: decrypt with own private key
$decryptor = new Decryptor(
    new RsaKeyUnwrapper($privateKey),
    new Aes256GcmFactory(),
);

$plaintext = $decryptor->decrypt($serializer->unserialize($compactJwe));
// "Secret message"

To generate a key pair:

openssl genrsa -out private.pem 2048
openssl rsa -in private.pem -pubout -out public.pem

AutoDecryptor — algorithm-agnostic decryption

AutoDecryptor reads the algorithm identifiers from the JWE protected header at runtime and selects the correct unwrapper and cipher automatically. Register the algorithms you want to support once, then decrypt any compatible token.

use Silencenjoyer\Jwe\Ciphers\Factory\Aes256CbcFactory;
use Silencenjoyer\Jwe\Ciphers\Factory\Aes256GcmFactory;
use Silencenjoyer\Jwe\Decryptors\AutoDecryptor;
use Silencenjoyer\Jwe\KeyEncapsulation\DirectKeyUnwrapper;
use Silencenjoyer\Jwe\KeyEncapsulation\RsaKeyUnwrapper;
use Silencenjoyer\Jwe\Keys\Key;
use Silencenjoyer\Jwe\Serializers\CompactSerializer;

$privateKey = Key::fromPath('/path/to/private.pem');
$sharedKey  = Key::fromContent('a-32-byte-secret-key-goes-here!!');

$decryptor = (new AutoDecryptor())
    // Key encapsulation algorithms
    ->addUnwrapper(new RsaKeyUnwrapper($privateKey))   // handles alg=RSA-OAEP
    ->addUnwrapper(new DirectKeyUnwrapper($sharedKey)) // handles alg=dir
    // Content encryption algorithms
    ->addCipherFactory(new Aes256GcmFactory())         // handles enc=A256GCM
    ->addCipherFactory(new Aes256CbcFactory());        // handles enc=A256CBC-HS512

$serializer = new CompactSerializer();

// Works for any combination of the registered algorithms
$plaintext = $decryptor->decrypt($serializer->unserialize($compactJwe));

If the token uses an algorithm that was not registered, UnsupportedAlgorithmException is thrown.

Serialization formats

The library supports both JWE serialization formats defined in RFC 7516.

Compact serialization — five base64url parts separated by dots, suitable for HTTP headers and URLs:

use Silencenjoyer\Jwe\Serializers\CompactSerializer;

$serializer = new CompactSerializer();
$compact    = $serializer->serialize($token);   // "header.enckey.iv.ciphertext.tag"
$token      = $serializer->unserialize($compact);

JSON serialization — a JSON object, easier to inspect and log:

use Silencenjoyer\Jwe\Serializers\JsonSerializer;

$serializer = new JsonSerializer();
$json       = $serializer->serialize($token);
// {
//   "protected": "...",
//   "encrypted_key": "...",
//   "iv": "...",
//   "ciphertext": "...",
//   "tag": "..."
// }
$token = $serializer->unserialize($json);

Loading keys

use Silencenjoyer\Jwe\Keys\Key;

// From a PEM file on disk
$key = Key::fromPath('/path/to/key.pem');

// From a string (e.g. an environment variable or a secrets manager)
$key = Key::fromContent(getenv('SHARED_SECRET'));

⚒️ Code Quality:

• Tests: composer test
• Static analysis: composer phpstan
• PSR-12 formatting

License

MIT