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, JWS, JWE, JWK and JWA RFC specifications.
Use your favorite Maven-compatible build tool to pull the dependency (and its transitive dependencies) from Maven Central:
Maven:
<dependency>
<groupId>io.jsonwebtoken</groupId>
<artifactId>jjwt</artifactId>
<version>0.6.0</version>
</dependency>
Gradle:
dependencies {
compile 'io.jsonwebtoken:jjwt:0.6.0'
}
Note: JJWT depends on Jackson 2.x. If you're already using an older version of Jackson in your app, read this
Most complexity is hidden behind a convenient and readable builder-based fluent interface, great for relying on IDE auto-completion to write code quickly. Here's an example:
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.impl.crypto.MacProvider;
import java.security.Key;
// We need a signing key, so we'll create one just for this example. Usually
// the key would be read from your application configuration instead.
Key key = MacProvider.generateKey();
String s = Jwts.builder().setSubject("Joe").signWith(SignatureAlgorithm.HS512, key).compact();
How easy was that!?
Now let's verify the JWT (you should always discard JWTs that don't match an expected signature):
assert Jwts.parser().setSigningKey(key).parseClaimsJws(s).getBody().getSubject().equals("Joe");
You have to love one-line code snippets!
But what if signature validation failed? You can catch SignatureException
and react accordingly:
try {
Jwts.parser().setSigningKey(key).parseClaimsJws(compactJwt);
//OK, we can trust this JWT
} catch (SignatureException e) {
//don't trust the JWT!
}
-
Creating and parsing plaintext compact JWTs
-
Creating, parsing and verifying digitally signed compact JWTs (aka JWSs) with all standard JWS algorithms:
- HS256: HMAC using SHA-256
- 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
- ES256: ECDSA using P-256 and SHA-256
- ES384: ECDSA using P-384 and SHA-384
- ES512: ECDSA using P-512 and SHA-512
- Non-compact serialization and parsing.
- JWE (Encryption for JWT)
These feature sets will be implemented in a future release when possible. Community contributions are welcome!
You can now enforce that JWT claims have expected values when parsing a compact JWT string.
For example, let's say that you require that the JWT you are parsing has a specific sub
(subject) value,
otherwise you may not trust the token. You can do that by using one of the require
methods on the parser builder:
try {
Jwts.parser().requireSubject("jsmith").setSigningKey(key).parseClaimsJws(s);
} catch(InvalidClaimException ice) {
// the sub field was missing or did not have a 'jsmith' value
}
If it is important to react to a missing vs an incorrect value, instead of catching InvalidClaimException
, you can catch either MissingClaimException
or IncorrectClaimException
:
try {
Jwts.parser().requireSubject("jsmith").setSigningKey(key).parseClaimsJws(s);
} catch(MissingClaimException mce) {
// the parsed JWT did not have the sub field
} catch(IncorrectClaimException ice) {
// the parsed JWT had a sub field, but its value was not equal to 'jsmith'
}
You can also require custom fields by using the require(fieldName, requiredFieldValue)
method - for example:
try {
Jwts.parser().require("myfield", "myRequiredValue").setSigningKey(key).parseClaimsJws(s);
} catch(InvalidClaimException ice) {
// the 'myfield' field was missing or did not have a 'myRequiredValue' value
}
(or, again, you could catch either MissingClaimException or IncorrectClaimException instead)
This feature is NOT JWT specification compliant, but it can be very useful when you parse your own tokens.
If your JWT body is large and you have size restrictions (for example, if embedding a JWT in a URL and the URL must be under a certain length for legacy browsers or mail user agents), you may now compress the JWT body using a CompressionCodec
:
Jwts.builder().claim("foo", "someReallyLongDataString...")
.compressWith(CompressionCodecs.DEFLATE) // or CompressionCodecs.GZIP
.signWith(SignatureAlgorithm.HS256, key)
.compact();
This will set a new calg
header with the name of the compression algorithm used so that parsers can see that value and decompress accordingly.
The default parser implementation will automatically decompress DEFLATE or GZIP compressed bodies, so you don't need to set anything on the parser - it looks like normal:
Jwts.parser().setSigningKey(key).parseClaimsJws(compact);
If the DEFLATE or GZIP algorithms are not sufficient for your needs, you can specify your own Compression algorithms by implementing the CompressionCodec
interface and setting it on the parser:
Jwts.builder().claim("foo", "someReallyLongDataString...")
.compressWith(new MyCompressionCodec())
.signWith(SignatureAlgorithm.HS256, key)
.compact();
You will then need to specify a CompressionCodecResolver
on the parser, so you can inspect the calg
header and return your custom codec when discovered:
Jwts.parser().setSigningKey(key)
.setCompressionCodecResolver(new MyCustomCompressionCodecResolver())
.parseClaimsJws(compact);
NOTE: Because body compression is not JWT specification compliant, you should only enable compression if both your JWT builder and parser are JJWT versions >= 0.6.0, or if you're using another library that implements the exact same functionality. This feature is best reserved for your own use cases - where you both create and later parse the tokens. It will likely cause problems if you compressed a token and expected a 3rd party (who doesn't use JJWT) to parse the token.
-
Android support! Android's built-in Base64 codec will be used if JJWT detects it is running in an Android environment. Other than Base64, all other parts of JJWT were already Android-compliant. Now it is fully compliant.
-
Elliptic Curve signature algorithms!
SignatureAlgorithm.ES256
,ES384
andES512
are now supported. -
Super convenient key generation methods, so you don't have to worry how to do this safely:
MacProvider.generateKey(); //or generateKey(SignatureAlgorithm)
RsaProvider.generateKeyPair(); //or generateKeyPair(sizeInBits)
EllipticCurveProvider.generateKeyPair(); //or generateKeyPair(SignatureAlgorithm)
The
generate
* methods that accept anSignatureAlgorithm
argument know to generate a key of sufficient strength that reflects the specified algorithm strength.
Please see the full 0.5 closed issues list for more information.
- Issue 8: Add ability to find signing key by inspecting the JWS values before verifying the signature.
This is a handy little feature. If you need to parse a signed JWT (a JWS) and you don't know which signing key was used to sign it, you can now use the new SigningKeyResolver
concept.
A SigningKeyresolver
can inspect the JWS header and body (Claims or String) before the JWS signature is verified. By inspecting the data, you can find the key and return it, and the parser will use the returned key to validate the signature. For example:
SigningKeyResolver resolver = new MySigningKeyResolver();
Jws<Claims> jws = Jwts.parser().setSigningKeyResolver(resolver).parseClaimsJws(compact);
The signature is still validated, and the JWT instance will still not be returned if the jwt string is invalid, as expected. You just get to 'see' the JWT data for key discovery before the parser validates. Nice.
This of course requires that you put some sort of information in the JWS when you create it so that your SigningKeyResolver
implementation can look at it later and look up the key. The standard way to do this is to use the JWS kid
('key id') field, for example:
Jwts.builder().setHeaderParam("kid", your_signing_key_id_NOT_THE_SECRET).build();
You could of course set any other header parameter or claims parameter instead of setting kid
if you want - that's just the default field reserved for signing key identification. If you can locate the signing key based on other information in the header or claims, you don't need to set the kid
field - just make sure your resolver implementation knows how to look up the key.
Finally, a nice SigningKeyResolverAdapter
is provided to allow you to write quick and simple subclasses or anonymous classes instead of having to implement the SigningKeyResolver
interface directly. For example:
Jws<Claims> jws = Jwts.parser().setSigningKeyResolver(new SigningKeyResolverAdapter() {
@Override
public byte[] resolveSigningKeyBytes(JwsHeader header, Claims claims) {
//inspect the header or claims, lookup and return the signing key
String keyId = header.getKeyId(); //or any other field that you need to inspect
return getSigningKey(keyId); //implement me
}})
.parseClaimsJws(compact);
- Issue 6: Parsing an expired Claims JWT or JWS (as determined by the
exp
claims field) will now throw anExpiredJwtException
. - Issue 7: Parsing a premature Claims JWT or JWS (as determined by the
nbf
claims field) will now throw aPrematureJwtException
.
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:
Claims claims = Jwts.claims().setSubject("Joe");
String compactJwt = Jwts.builder().setClaims(claims).signWith(HS256, key).compact();
can now be written as:
String compactJwt = Jwts.builder().setSubject("Joe").signWith(HS256, key).compact();
A Claims instance based on the specified claims will be created and set as the JWT's payload automatically.
The following < 0.2 code produced a JWT as expected:
Jwt jwt = Jwts.parser().setSigningKey(key).parse(compact);
But you couldn't easily determine if the jwt
was a JWT
or JWS
instance or if the body was a Claims
instance or a plaintext String
without resorting to a bunch of yucky instanceof
checks. In 0.2, we introduce the JwtHandler
when you don't know the exact format of the compact JWT string ahead of time, and parsing convenience methods when you do.
If you do not know the format of the compact JWT string at the time you try to parse it, you can determine what type it is after parsing by providing a JwtHandler
instance to the JwtParser
with the new parse(String compactJwt, JwtHandler handler)
method. For example:
T returnVal = Jwts.parser().setSigningKey(key).parse(compact, new JwtHandler<T>() {
@Override
public T onPlaintextJwt(Jwt<Header, String> jwt) {
//the JWT parsed was an unsigned plaintext JWT
//inspect it, then return an instance of T (see returnVal above)
}
@Override
public T onClaimsJwt(Jwt<Header, Claims> jwt) {
//the JWT parsed was an unsigned Claims JWT
//inspect it, then return an instance of T (see returnVal above)
}
@Override
public T onPlaintextJws(Jws<String> jws) {
//the JWT parsed was a signed plaintext JWS
//inspect it, then return an instance of T (see returnVal above)
}
@Override
public T onClaimsJws(Jws<Claims> jws) {
//the JWT parsed was a signed Claims JWS
//inspect it, then return an instance of T (see returnVal above)
}
});
Of course, if you know you'll only have to parse a subset of the above, you can use the JwtHandlerAdapter
and implement only the methods you need. For example:
T returnVal = Jwts.parser().setSigningKey(key).parse(plaintextJwt, new JwtHandlerAdapter<Jwt<Header, T>>() {
@Override
public T onPlaintextJws(Jws<String> jws) {
//the JWT parsed was a signed plaintext JWS
//inspect it, then return an instance of T (see returnVal above)
}
@Override
public T onClaimsJws(Jws<Claims> jws) {
//the JWT parsed was a signed Claims JWS
//inspect it, then return an instance of T (see returnVal above)
}
});
If, unlike above, you are confident of the compact string format and know which type of JWT or JWS it will produce, you can just use one of the 4 new convenience parsing methods to get exactly the type of JWT or JWS you know exists. For example:
//for a known plaintext jwt string:
Jwt<Header,String> jwt = Jwts.parser().parsePlaintextJwt(compact);
//for a known Claims JWT string:
Jwt<Header,Claims> jwt = Jwts.parser().parseClaimsJwt(compact);
//for a known signed plaintext JWT (aka a plaintext JWS):
Jws<String> jws = Jwts.parser().setSigningKey(key).parsePlaintextJws(compact);
//for a known signed Claims JWT (aka a Claims JWS):
Jws<Claims> jws = Jwts.parser().setSigningKey(key).parseClaimsJws(compact);
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. To avoid this, you should change your project build configuration to explicitly point to a 2.x version of Jackson. For example:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.4.2</version>
</dependency>