jose4j

Facts and the checks behind them

Nothing below is copied from documentation. The check content/libraries/verify/jose4j/run.sh ran jose4j 0.9.7 in the container image maven:3.9.16-eclipse-temurin-25 on October 20, 2026; the page must match what it printed, and each fact lists those lines.

• JWS algorithms

  HS256HS384HS512RS256RS384RS512PS256PS384PS512ES256ES384ES512EdDSA

  HS, RS, PS and ES at 256/384/512 and EdDSA signed and verified; ES256K, Ed25519 and Ed448 raised InvalidAlgorithmException.

  Recorded by the check

  fact jws-algorithms = HS256, HS384, HS512, RS256, RS384, RS512, PS256, PS384, PS512, ES256, ES384, ES512, EdDSA
  evidence jws-algorithms: ES256K: InvalidAlgorithmException: ES256K is an unknown, unsupported or unavailable alg algorithm (not one of [none, HS256, HS384, HS512, EdDSA, ES256, ES384, ES512, RS256, RS384, RS512, PS256, PS384, PS512]).
  evidence jws-algorithms: Ed25519: InvalidAlgorithmException: Ed25519 is an unknown, unsupported or unavailable alg algorithm (not one of [none, HS256, HS384, HS512, EdDSA, ES256, ES384, ES512, RS256, RS384, RS512, PS256, PS384, PS512]).
  evidence jws-algorithms: Ed448: InvalidAlgorithmException: Ed448 is an unknown, unsupported or unavailable alg algorithm (not one of [none, HS256, HS384, HS512, EdDSA, ES256, ES384, ES512, RS256, RS384, RS512, PS256, PS384, PS512]).

• ES256 signature encoding

  raw

  ES256 signatures are 64 bytes of raw r‖s.

  Recorded by the check

  fact jws-ecdsa-encoding = raw

• DER signature inside a JWS

  rejected

  A DER-encoded ES256 signature fails with InvalidJwtSignatureException: JWT rejected due to invalid signature.

  Recorded by the check

  fact jws-der-signature = rejected
  evidence jws-der-signature: InvalidJwtSignatureException: JWT rejected due to invalid signature. Additional details: [[9] Invalid JWS Signature:

• Algorithm allow-list

  from-key

  Without algorithm constraints the key type decides: an RS256 token against an EC key failed with The given key (algorithm=EC) is not valid for SHA256withRSA.

  Recorded by the check

  fact jwt-algorithm-allowlist = from-key
  evidence jwt-algorithm-allowlist: JwtConsumer without algorithm constraints, RS256 token against an EC key: InvalidJwtException: JWT processing failed. Additional details: [[17] Unable to process JOSE object (cause: org.jose4j.lang.InvalidKeyException: The given key (algorithm=EC) is not valid for SHA256withRSA):

• Unsigned tokens (alg none)

  opt-in

  The default consumer refuses unsigned tokens with 'none' is a blocked algorithm.; setDisableRequireSignature() with no algorithm constraints accepts them.

  Recorded by the check

  fact jwt-alg-none = opt-in
  evidence jwt-alg-none: default JwtConsumer: InvalidJwtException: JWT processing failed. Additional details: [[17] Unable to process JOSE object (cause: org.jose4j.lang.InvalidAlgorithmException: 'none' is a blocked algorithm.):
  evidence jwt-alg-none: setDisableRequireSignature with no algorithm constraints: verified

• Public key used as an HMAC secret

  rejected

  An HS256 token keyed with the PEM text failed against the EC public key, but an HmacKey built from the PEM bytes verified it.

  Recorded by the check

  fact jwt-hmac-public-key = rejected
  evidence jwt-hmac-public-key: JwtConsumer with the EC public key: InvalidJwtException: JWT processing failed. Additional details: [[17] Unable to process JOSE object (cause: org.jose4j.lang.InvalidKeyException: class sun.security.ec.ECPublicKeyImpl cannot be used for HMAC verification.):
  evidence jwt-hmac-public-key: JwtConsumer with an HmacKey built from the PEM bytes: verified

• Curve checked against alg

  enforced

  Signing ES256 with a P-384 key fails with ES256/SHA256withECDSA expects a key using P-256 but was P-384.

  Recorded by the check

  fact jwt-ecdsa-curve-check = enforced
  evidence jwt-ecdsa-curve-check: InvalidKeyException: ES256/SHA256withECDSA expects a key using P-256 but was P-384

• Default clock skew

  0s

  No clock skew allowance by default: a token expired three seconds earlier was rejected.

  Recorded by the check

  fact jwt-clock-skew = 0s

• Expiry claim required

  no

  A token without exp was accepted; setRequireExpirationTime() requires it.

  Recorded by the check

  fact jwt-exp-required = no

• Short HMAC secret

  rejected

  HS256 refused a 16-byte key: A key of the same size as the hash output ... or larger MUST be used.

  Recorded by the check

  fact jwt-hmac-short-secret = rejected
  evidence jwt-hmac-short-secret: HS256 with a 16-byte key: InvalidKeyException: A key of the same size as the hash output (i.e. 256 bits for HS256) or larger MUST be used with the HMAC SHA algorithms but this key is only 128 bits

Usage

import org.jose4j.jwa.AlgorithmConstraints.ConstraintType;
import org.jose4j.jwk.EcJwkGenerator;
import org.jose4j.jwk.EllipticCurveJsonWebKey;
import org.jose4j.jws.AlgorithmIdentifiers;
import org.jose4j.jws.JsonWebSignature;
import org.jose4j.jwt.JwtClaims;
import org.jose4j.jwt.consumer.JwtConsumer;
import org.jose4j.jwt.consumer.JwtConsumerBuilder;
import org.jose4j.keys.EllipticCurves;

public class Usage {
    public static void main(String[] args) throws Exception {
        EllipticCurveJsonWebKey key = EcJwkGenerator.generateJwk(EllipticCurves.P256);
        JwtClaims claims = new JwtClaims();
        claims.setSubject("user-42");
        claims.setIssuer("https://auth.example.com");
        claims.setExpirationTimeMinutesInTheFuture(10);

        JsonWebSignature jws = new JsonWebSignature();
        jws.setPayload(claims.toJson());
        jws.setAlgorithmHeaderValue(AlgorithmIdentifiers.ECDSA_USING_P256_CURVE_AND_SHA256);
        jws.setKey(key.getPrivateKey());

        // Pin the algorithm and require exp; the defaults would allow any non-'none' alg for the key.
        JwtConsumer consumer = new JwtConsumerBuilder()
            .setJwsAlgorithmConstraints(ConstraintType.PERMIT, AlgorithmIdentifiers.ECDSA_USING_P256_CURVE_AND_SHA256)
            .setVerificationKey(key.getPublicKey())
            .setExpectedIssuer("https://auth.example.com")
            .setRequireExpirationTime()
            .setAllowedClockSkewInSeconds(30)
            .build();
        System.out.println("sub: " + consumer.processToClaims(jws.getCompactSerialization()).getSubject());
    }
}