> For the complete documentation index, see [llms.txt](https://web-token.spomky-labs.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://web-token.spomky-labs.com/the-components/examples/signed-tokens.md).

# Signed Tokens (JWS)

## Sign a Token with HMAC (HS256)

The simplest approach: a shared secret key is used to both sign and verify the token.

```php
<?php

use Jose\Component\Core\AlgorithmManager;
use Jose\Component\Core\JWK;
use Jose\Component\Signature\Algorithm\HS256;
use Jose\Component\Signature\JWSBuilder;
use Jose\Component\Signature\Serializer\CompactSerializer;

require_once 'vendor/autoload.php';

// Create a symmetric key (shared secret)
$jwk = new JWK([
    'kty' => 'oct',
    'k' => base64_encode(random_bytes(32)), // 256-bit key
]);

$algorithmManager = new AlgorithmManager([new HS256()]);
$jwsBuilder = new JWSBuilder($algorithmManager);

$payload = json_encode([
    'iss' => 'https://my-app.example.com',
    'aud' => 'https://api.example.com',
    'sub' => 'user-42',
    'iat' => time(),
    'exp' => time() + 3600,
]);

$jws = $jwsBuilder
    ->create()
    ->withPayload($payload)
    ->addSignature($jwk, ['alg' => 'HS256'])
    ->build();

$token = (new CompactSerializer())->serialize($jws);
// eyJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJodHRwczovL215LWFwcC...
```

### Verify the Token

```php
<?php

use Jose\Component\Core\AlgorithmManager;
use Jose\Component\Core\JWK;
use Jose\Component\Signature\Algorithm\HS256;
use Jose\Component\Signature\JWSVerifier;
use Jose\Component\Signature\Serializer\CompactSerializer;

require_once 'vendor/autoload.php';

$jwk = /* the same shared key used for signing */;

$algorithmManager = new AlgorithmManager([new HS256()]);
$jwsVerifier = new JWSVerifier($algorithmManager);

$jws = (new CompactSerializer())->unserialize($token);

$isValid = $jwsVerifier->verifyWithKey($jws, $jwk, 0);
// $isValid is true if the signature is valid
```

***

## Sign a Token with RSA (RS256)

RSA keys allow the signer and the verifier to use different keys: a private key to sign, a public key to verify.

```php
<?php

use Jose\Component\Core\AlgorithmManager;
use Jose\Component\KeyManagement\JWKFactory;
use Jose\Component\Signature\Algorithm\RS256;
use Jose\Component\Signature\JWSBuilder;
use Jose\Component\Signature\Serializer\CompactSerializer;

require_once 'vendor/autoload.php';

// Generate an RSA key pair (2048-bit minimum recommended)
$privateKey = JWKFactory::createRSAKey(2048, ['alg' => 'RS256', 'use' => 'sig']);

$algorithmManager = new AlgorithmManager([new RS256()]);
$jwsBuilder = new JWSBuilder($algorithmManager);

$payload = json_encode([
    'iss' => 'https://auth.example.com',
    'aud' => 'https://api.example.com',
    'sub' => 'user-42',
    'iat' => time(),
    'exp' => time() + 3600,
]);

$jws = $jwsBuilder
    ->create()
    ->withPayload($payload)
    ->addSignature($privateKey, ['alg' => 'RS256'])
    ->build();

$token = (new CompactSerializer())->serialize($jws);
```

### Verify with the Public Key

```php
<?php

use Jose\Component\Core\AlgorithmManager;
use Jose\Component\Signature\Algorithm\RS256;
use Jose\Component\Signature\JWSVerifier;
use Jose\Component\Signature\Serializer\CompactSerializer;

require_once 'vendor/autoload.php';

// Extract the public key from the private key
$publicKey = $privateKey->toPublic();

$algorithmManager = new AlgorithmManager([new RS256()]);
$jwsVerifier = new JWSVerifier($algorithmManager);

$jws = (new CompactSerializer())->unserialize($token);

$isValid = $jwsVerifier->verifyWithKey($jws, $publicKey, 0);
```

***

## Sign a Token with Elliptic Curve (ES256)

ECDSA keys are smaller and faster than RSA for the same security level.

```php
<?php

use Jose\Component\Core\AlgorithmManager;
use Jose\Component\KeyManagement\JWKFactory;
use Jose\Component\Signature\Algorithm\ES256;
use Jose\Component\Signature\JWSBuilder;
use Jose\Component\Signature\Serializer\CompactSerializer;

require_once 'vendor/autoload.php';

// Generate an EC key on the P-256 curve
$privateKey = JWKFactory::createECKey('P-256', ['alg' => 'ES256', 'use' => 'sig']);

$algorithmManager = new AlgorithmManager([new ES256()]);
$jwsBuilder = new JWSBuilder($algorithmManager);

$payload = json_encode([
    'iss' => 'https://auth.example.com',
    'aud' => 'https://api.example.com',
    'sub' => 'user-42',
    'iat' => time(),
    'exp' => time() + 3600,
]);

$jws = $jwsBuilder
    ->create()
    ->withPayload($payload)
    ->addSignature($privateKey, ['alg' => 'ES256'])
    ->build();

$token = (new CompactSerializer())->serialize($jws);
```

### Verify with the Public Key

```php
<?php

use Jose\Component\Core\AlgorithmManager;
use Jose\Component\Signature\Algorithm\ES256;
use Jose\Component\Signature\JWSVerifier;
use Jose\Component\Signature\Serializer\CompactSerializer;

require_once 'vendor/autoload.php';

$publicKey = $privateKey->toPublic();

$algorithmManager = new AlgorithmManager([new ES256()]);
$jwsVerifier = new JWSVerifier($algorithmManager);

$jws = (new CompactSerializer())->unserialize($token);

$isValid = $jwsVerifier->verifyWithKey($jws, $publicKey, 0);
```

***

## Sign a Token with EdDSA (Ed25519)

EdDSA with Ed25519 provides high performance and strong security. Requires the `sodium` extension.

```php
<?php

use Jose\Component\Core\AlgorithmManager;
use Jose\Component\KeyManagement\JWKFactory;
use Jose\Component\Signature\Algorithm\EdDSA;
use Jose\Component\Signature\JWSBuilder;
use Jose\Component\Signature\Serializer\CompactSerializer;

require_once 'vendor/autoload.php';

// Generate an Ed25519 key pair (requires ext-sodium)
$privateKey = JWKFactory::createOKPKey('Ed25519', ['alg' => 'EdDSA', 'use' => 'sig']);

$algorithmManager = new AlgorithmManager([new EdDSA()]);
$jwsBuilder = new JWSBuilder($algorithmManager);

$payload = json_encode([
    'iss' => 'https://auth.example.com',
    'sub' => 'user-42',
    'iat' => time(),
    'exp' => time() + 3600,
]);

$jws = $jwsBuilder
    ->create()
    ->withPayload($payload)
    ->addSignature($privateKey, ['alg' => 'EdDSA'])
    ->build();

$token = (new CompactSerializer())->serialize($jws);

// Verification
$publicKey = $privateKey->toPublic();
$jwsVerifier = new \Jose\Component\Signature\JWSVerifier($algorithmManager);
$jws = (new CompactSerializer())->unserialize($token);
$isValid = $jwsVerifier->verifyWithKey($jws, $publicKey, 0);
```

***

## Using the JWSLoader (Recommended)

The `JWSLoader` combines deserialization, header checking, and signature verification in a single step. This is the recommended approach for loading tokens.

```php
<?php

use Jose\Component\Checker\AlgorithmChecker;
use Jose\Component\Checker\HeaderCheckerManager;
use Jose\Component\Core\AlgorithmManager;
use Jose\Component\Core\JWK;
use Jose\Component\Signature\Algorithm\HS256;
use Jose\Component\Signature\JWSLoader;
use Jose\Component\Signature\JWSTokenSupport;
use Jose\Component\Signature\JWSVerifier;
use Jose\Component\Signature\Serializer\CompactSerializer;
use Jose\Component\Signature\Serializer\JWSSerializerManager;

require_once 'vendor/autoload.php';

$jwk = /* your verification key */;

$algorithmManager = new AlgorithmManager([new HS256()]);

$jwsLoader = new JWSLoader(
    new JWSSerializerManager([new CompactSerializer()]),
    new JWSVerifier($algorithmManager),
    new HeaderCheckerManager(
        [new AlgorithmChecker(['HS256'])],  // Only allow HS256
        [new JWSTokenSupport()]
    )
);

$signature = null;
$jws = $jwsLoader->loadAndVerifyWithKey($token, $jwk, $signature);

$payload = json_decode($jws->getPayload(), true);
```

{% hint style="info" %}
After verifying the signature, you should also validate the claims (`exp`, `iss`, `aud`, etc.). See the [Claim and Header Validation](/the-components/examples/validation.md) page.
{% endhint %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://web-token.spomky-labs.com/the-components/examples/signed-tokens.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.