jwt Signature exception while decoding - jwt

Question

I am facing Signature exception while adding security to my Spring Rest services. Please help.
io.jsonwebtoken.SignatureException: JWT signature does not match locally computed signature. JWT validity cannot be asserted and should not be trusted.
at io.jsonwebtoken.impl.DefaultJwtParser.parse(DefaultJwtParser.java:354)
//Make Token
String token = Jwts.builder()
.setSubject(((User) auth.getPrincipal()).getUsername())
.signWith(SignatureAlgorithm.HS512, SECRET.getBytes("UTF-8"))
.compact();
res.addHeader(HEADER_STRING, TOKEN_PREFIX + token);
// Decoding token
String token = request.getHeader(HEADER_STRING);
if (token != null) {
// parse the token.
String jwt = token.replace(TOKEN_PREFIX, "");
try {
Claims claims = Jwts.parser()
.setSigningKey(SECRET.getBytes("UTF-8"))
.parseClaimsJws(jwt)
.getBody();
if (claims.getSubject() != null) {
return new UsernamePasswordAuthenticationToken(claims.getSubject(), null, getAuthorities());
}
}
When I am printing both, I am getting the below text. One is having extra space. This is happening only when I am hitting the service using Rest client. Test classes are working fine.
makeToken= eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJza3AifQ.XUEsUFF3qm6fOeCG8xDLuRWjyd4kOh4g01olU_BsRyfqyI66MRhqmK-mxrAWsD17Ylmj-fZRRZUTRqxCQixxXQ
decodeToken=
eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJza3AifQ.XUEsUFF3qm6fOeCG8xDLuRWjyd4kOh4g01olU_BsRyfqyI66MRhqmK-mxrAWsD17Ylmj-fZRR ZUTRqxCQixxXQ

Answer 1

It's late but worth If someone is facing the same issue while decoding JWT token.
Library GitHub link:
https://github.com/auth0/JWTDecode.Android
Implementation:
implementation ('com.auth0.android:jwtdecode:1.2.0'){
exclude group: 'com.android.support', module: 'appcompat-v7'
}
Code:
// token: eyJ0eXAiOiJKV1QiLCJhbxxxxxxx9.eyJpZC*********************UEFUSUVOVCIsImV4cCI6MTU2NTY5MzU5MCwib3JpZ0lhdCI6MTU2NTA4ODc5MH0.ZhPpZSFZL6EY-Mwrw0F*********MYmbw
private void getExpDate(String token) {
JWT jwt = new JWT(token);
Log.e(TAG,"Claim - id:"+jwt.getClaim("id").asString()+" - username:"+jwt.getClaim("username").asString()+" - role:"+jwt.getClaim("role").asString()+" - exp:"+jwt.getClaim("exp").asString());
}
Logcat Result:
E/PatientLogin: Claim - id:cd5dbe61-xxxx-xxxx-xxxx-xxxxxx - username:xxxx#gmail.com - role:PATIENT - exp:1565693590
Test JWT Token:
If you want to check your JWT token then use below link.
https://jwt.io/
OR
Here is another method which might work for you as well. This will help to avoid using a third-party library.
Reference: Orignal post
decoded(token);
public static String decoded(String JWTEncoded) {
String[] split = JWTEncoded.split("\\.");
Log.e(TAG, "Header: " + getJson(split[0]));
Log.e(TAG, "Body: " + getJson(split[1]));
return getJson(split[1]);
}
private static String getJson(String strEncoded){
String str_dec = "";
try {
byte[] decodedBytes = Base64.decode(strEncoded, Base64.URL_SAFE);
str_dec = new String(decodedBytes, "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return str_dec;
}