I am trying to read a Json Web Token(JWT) generated from Google OpenID Connect's Id Token in order to get the claims and to verify using jjwt library. I have tried several ways to fix it with the code below.
String publicKeyFromJsonFile = "-----BEGIN PUBLIC KEY-----xxxxxxx-----END PUBLIC KEY-----"
Claims claims = Jwts.parser()
.setSigningKey(publicKeyFromJsonFile)
.parseClaimsJws(jwt).getBody();
System.out.println(claims);
but I am getting this error:
java.lang.IllegalArgumentException: Key bytes can only be specified for HMAC signatures. Please specify a PublicKey or PrivateKey instance
Please what could be the right approach to follow ?
I think I have been able to fix the gotcha by parsing the publicKey as an RSAPublicKey
. Below is the nitty-gritty of how i went about it.
public static Optional<RSAPublicKey> getParsedPublicKey(){
// public key content...excluding '---PUBLIC KEY---' and '---END PUBLIC KEY---'
String PUB_KEY =System.getenv("PUBLIC_KEY") ;
// removes white spaces or char 20
String PUBLIC_KEY = "";
if (!PUB_KEY.isEmpty()) {
PUBLIC_KEY = PUB_KEY.replace(" ", "");
}
try {
byte[] decode = com.google.api.client.util.Base64.decodeBase64(PUBLIC_KEY);
X509EncodedKeySpec keySpecX509 = new X509EncodedKeySpec(decode);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
RSAPublicKey pubKey = (RSAPublicKey) keyFactory.generatePublic(keySpecX509);
return Optional.of(pubKey);
} catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
e.printStackTrace();
System.out.println("Exception block | Public key parsing error ");
return Optional.empty();
}
Hope it helps :).