I have a JWT that looks like this (I had to hide some values):
eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiJ4eHgiLCJpc3MiOiJ4eHgiLCJpYXQiOjE2MTIzNDkwMTEsIm5iZiI6MCwiZXhwIjoxNjEyMzUyNjExLCJhdXRoX3RpbWUiOjE2MTEwNDU5MjgsIm5vbmNlIjoieHh4Iiwic3ViIjoieHh4IiwidXBuIjoieHh4IiwidW5pcXVlX25hbWUiOiJ4eHgiLCJwd2RfdXJsIjoieHh4IiwicHdkX2V4cCI6Inh4eCIsInNpZCI6Inh4eCIsImp0aSI6ImZmYWQ0NjM1LTU3MmItNGUyYi04ZGRhLTAxNmEzNDRlYzY4ZiJ9.nW5xTs6IbEkIFTZ_9PJZBpZAHXqG2HeU6y0XJwmQZiM
or simply:
{
"typ": "JWT",
"alg": "RS256",
"x5t": "8Q3reRBv6jj6FyxBo5phA1yKzYg",
"kid": "8Q3reRBv6jj6FyxBo5phA1yKzYg"
}
and
{
"aud": "xxx",
"iss": "xxx",
"iat": 0,
"nbf": 0,
"exp": 1611049528,
"auth_time": 1611045928,
"nonce": "xxx",
"sub": "xxx",
"upn": "xxx",
"unique_name": "xxx",
"pwd_url": "xxx",
"pwd_exp": "xxx",
"sid": "xxx"
}
This is the code I wrote to verify it (starting from the examples in the website).
@SneakyThrows
public boolean isValid(String extractedToken) {
log.info("Validating JWT");
// Generate an RSA key pair, which will be used for signing and verification of the JWT, wrapped in a JWK
RsaJsonWebKey rsaJsonWebKey = RsaJwkGenerator.generateJwk(2048);
// Give the JWK a Key ID (kid), which is just the polite thing to do
rsaJsonWebKey.setKeyId("8Q3reRBv6jj6FyxBo5phA1yKzYg");
rsaJsonWebKey.setX509CertificateSha256Thumbprint("8Q3reRBv6jj6FyxBo5phA1yKzYg");
// Use JwtConsumerBuilder to construct an appropriate JwtConsumer, which will
// be used to validate and process the JWT.
// The specific validation requirements for a JWT are context dependent, however,
// it typically advisable to require a (reasonable) expiration time, a trusted issuer, and
// and audience that identifies your system as the intended recipient.
// If the JWT is encrypted too, you need only provide a decryption key or
// decryption key resolver to the builder.
JwtConsumer jwtConsumer = new JwtConsumerBuilder()
.setRequireExpirationTime() // the JWT must have an expiration time
.setAllowedClockSkewInSeconds(30) // allow some leeway in validating time based claims to account for clock skew
.setVerificationKey(rsaJsonWebKey.getKey()) // verify the signature with the public key
.setJwsAlgorithmConstraints( // only allow the expected signature algorithm(s) in the given context
AlgorithmConstraints.ConstraintType.PERMIT, AlgorithmIdentifiers.RSA_USING_SHA256) // which is only RS256 here
.build(); // create the JwtConsumer instance
try
{
// Validate the JWT and process it to the Claims
JwtClaims jwtClaims = jwtConsumer.processToClaims(extractedToken);
System.out.println("JWT validation succeeded! " + jwtClaims);
log.info("JTW validated");
return true;
}
catch (InvalidJwtException e)
{
// InvalidJwtException will be thrown, if the JWT failed processing or validation in anyway.
// Hopefully with meaningful explanations(s) about what went wrong.
System.out.println("Invalid JWT! " + e);
// Programmatic access to (some) specific reasons for JWT invalidity is also possible
// should you want different error handling behavior for certain conditions.
// Whether or not the JWT has expired being one common reason for invalidity
if (e.hasExpired())
{
System.out.println("JWT expired at " + e.getJwtContext().getJwtClaims().getExpirationTime());
}
// Or maybe the audience was invalid
if (e.hasErrorCode(ErrorCodes.AUDIENCE_INVALID))
{
System.out.println("JWT had wrong audience: " + e.getJwtContext().getJwtClaims().getAudience());
}
}
log.info("JTW validated");
return false;
}
My objective is to verify only the signature and no other key-pair value at the moment.
However, when I run the code, I get:
Invalid JWT! org.jose4j.jwt.consumer.InvalidJwtSignatureException: JWT rejected due to invalid signature. Additional details: [[9] Invalid JWS Signature: JsonWebSignature{"typ":"JWT","alg":"RS256","x5t":"8Q3reRBv6jj6FyxBo5phA1yKzYg","kid":"8Q3reRBv6jj6FyxBo5phA1yKzYg"}->eyJ0eXAiOi.....]
And the token in the right part of the "->" is indeed my token.
So I have the suspicion that I'm not properly setting up the JWTConsumer, but I cannot see where the error is.
WORKING SOLUTION:
@SneakyThrows
public boolean isValid(String extractedToken) {
log.info("Validating JWT");
String pem = "MIIBIj........DAQAB";
X509EncodedKeySpec pubKeySpec = new X509EncodedKeySpec(Base64.getMimeDecoder().decode(pem));
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(pubKeySpec);
// Use JwtConsumerBuilder to construct an appropriate JwtConsumer, which will
// be used to validate and process the JWT.
// The specific validation requirements for a JWT are context dependent, however,
// it typically advisable to require a (reasonable) expiration time, a trusted issuer, and
// and audience that identifies your system as the intended recipient.
// If the JWT is encrypted too, you need only provide a decryption key or
// decryption key resolver to the builder.
JwtConsumer jwtConsumer = new JwtConsumerBuilder()
.setVerificationKey(publicKey) // verify the signature with the public key
.setJwsAlgorithmConstraints( // only allow the expected signature algorithm(s) in the given context
AlgorithmConstraints.ConstraintType.PERMIT, AlgorithmIdentifiers.RSA_USING_SHA256) // which is only RS256 here
.setSkipAllDefaultValidators()
.build(); // create the JwtConsumer instance
try
{
// Validate the JWT and process it to the Claims
JwtClaims jwtClaims = jwtConsumer.processToClaims(extractedToken);
System.out.println("JWT validation succeeded! " + jwtClaims);
log.info("JTW validated");
return true;
}
catch (InvalidJwtException e)
{
// InvalidJwtException will be thrown, if the JWT failed processing or validation in anyway.
// Hopefully with meaningful explanations(s) about what went wrong.
System.out.println("Invalid JWT! " + e);
// Programmatic access to (some) specific reasons for JWT invalidity is also possible
// should you want different error handling behavior for certain conditions.
// Whether or not the JWT has expired being one common reason for invalidity
if (e.hasExpired())
{
System.out.println("JWT expired at " + e.getJwtContext().getJwtClaims().getExpirationTime());
}
// Or maybe the audience was invalid
if (e.hasErrorCode(ErrorCodes.AUDIENCE_INVALID))
{
System.out.println("JWT had wrong audience: " + e.getJwtContext().getJwtClaims().getAudience());
}
}
log.info("JTW validated");
return false;
}
