jjwt/README.md

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# Java JWT: JSON Web Token for Java
JJWT aims to be the easiest to use and understand library for creating and verifying JSON Web Tokens (JWTs) on the JVM.
JJWT is a 'clean room' implementation based solely on the [JWT](https://tools.ietf.org/html/draft-ietf-oauth-json-web-token-25), [JWS](https://tools.ietf.org/html/draft-ietf-jose-json-web-signature-31), [JWE](https://tools.ietf.org/html/draft-ietf-jose-json-web-encryption-31) and [JWA](https://tools.ietf.org/html/draft-ietf-jose-json-web-algorithms-31) RFC draft specifications.
## Installation
Use your favorite Maven-compatible build tool to pull the dependency (and its transitive dependencies) from Maven Central:
```xml
<dependency>
<groupId>io.jsonwebtoken</groupId>
<artifactId>jjwt</artifactId>
<version>0.1</version>
</dependency>
```
Note: JJWT depends on Jackson 2.x. If you're already using an older version of Jackson in your app, [read this](#olderJackson)
## Usage
Most complexity is hidden behind convenient and readable Builder chaining calls. Here's an example:
```java
import io.jsonwebtoken.Jwts;
import static io.jsonwebtoken.SignatureAlgorithm.*;
//Let's create a random signing key for testing:
Random random = new SecureRandom();
byte[] key = new byte[64];
random.nextBytes(key);
String compactJwt = Jwts.builder().setIssuer("Me").setSubject("Joe").signWith(HS256, key).compact();
```
How easy was that!?
Now let's verify the JWT (you should always discard JWTs that don't match an expected signature):
```java
Jwt jwt = Jwts.parser().setSigningKey(key).parse(compactJwt);
assert ((Claims)jwt.getBody()).getSubject().equals("Joe");
```
You have to love one-line code snippets in Java!
But what if signature validation failed? You can catch `SignatureException` and react accordingly:
```java
try {
Jwts.parser().setSigningKey(key).parse(compactJwt);
//OK, we can trust this JWT
} catch (SignatureException e) {
//don't trust the JWT!
}
```
## Supported Features
* Creating and parsing plaintext compact JWTs
* Creating, parsing and verifying digitally signed compact JWTs (aka JWSs) with the following algorithms:
* HS256: HMAC using SHA-384
* HS384: HMAC using SHA-384
* HS512: HMAC using SHA-512
* RS256: RSASSA-PKCS-v1_5 using SHA-256
* RS384: RSASSA-PKCS-v1_5 using SHA-384
* RS512: RSASSA-PKCS-v1_5 using SHA-512
* PS256: RSASSA-PSS using SHA-256 and MGF1 with SHA-256
* PS384: RSASSA-PSS using SHA-384 and MGF1 with SHA-384
* PS512: RSASSA-PSS using SHA-512 and MGF1 with SHA-512
## Currently Unsupported Features
* [Non-compact](https://tools.ietf.org/html/draft-ietf-jose-json-web-signature-31#section-7.2) serialization and parsing.
* Elliptic Curve signature algorithms `ES256`, `ES384` and `ES512`.
* JWE (Encryption for JWT)
These feature sets will be implemented in a future release when possible. Community contributions are welcome!
## Release Notes
### 0.2
#### More convenient Claims building
This release adds convenience methods to the `JwtBuilder` interface so you can set claims directly on the builder without having to create a separate Claims instance/builder, reducing the amount of code you have to write. For example, this:
```java
Claims claims = Jwts.claims().setIssuer("Me").setSubject("Joe");
String compactJwt = Jwts.builder().setClaims(claims).signWith(HS256, key).compact();
```
can now be written as:
```java
String compactJwt = Jwts.builder().setIssuer("Me").setSubject("Joe").signWith(HS256, key).compact();
```
and the JWT payload will use a constructed Claims instance automatically.
<a name="olderJackson"></a>
#### Already using an older Jackson dependency?
JJWT depends on Jackson 2.4.x (or later). If you are already using a Jackson version in your own application less than 2.x, for example 1.9.x, you will likely see [runtime errors](https://github.com/jwtk/jjwt/issues/1). To avoid this, you should change your project build configuration to explicitly point to a 2.x version of Jackson. For example:
```xml
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.4.2</version>
</dependency>
```