JWT Key encryption using RSA-OAEP-256

[amotupalli]

We are facing EJT error as below

ejt_error : AES/GCM/NoPadding decryption failed: Tag mismatch!

Can anyone please help on this.

Thank You,

Lakshmi.

EDITED

We are trying to JWT encrypted the data using below code

Client :

String accessToken = getPrudentialAccessToken(); // AccessToken
logger.debug("Plain Payload  : " + checkKycRequest.toString());
checkKycRequest.setTaxStatus("01");
checkKycRequest.setIsNewVersion("FTM");
checkKycRequest.setFirstPan("BDJPA0600D");
String jsonObject = new Gson().toJson(checkKycRequest);
logger.debug(jsonObject);
jsonObject = generatePublicKeyRsaInputEncryption(jsonObject);
logger.debug(jsonObject);
HttpEntity<String> entity = new HttpEntity<>(updateObjWithEmptyStrings(jsonObject, true),
                                        IciciPrudentialUtils.getHeader(accessToken));
String fullUrl = config.getOauthUrls().getCheckKyc();
logger.debug(fullUrl);
RestTemplate template = new RestTemplate();
ResponseEntity<String> tranResponseEntity = template.exchange(fullUrl, HttpMethod.POST, entity,
  String.class);

Encryption :

public static String getEncryptWithPublicKey(String payload) {
        JWEAlgorithm alg = JWEAlgorithm.RSA_OAEP_256;
        EncryptionMethod encryptionMethod = EncryptionMethod.A256GCM;
        try {
                RSAPublicKey key = readPublicKey();
                JWEObject jwe = new JWEObject(new JWEHeader(alg, encryptionMethod), new Payload(payload));
                jwe.encrypt(new RSAEncrypter(key));
                return jwe.serialize();
        } catch (Exception e) {
                logger.debug(e.getMessage());
        }
        return null;
}
public static RSAPublicKey readPublicKey() throws IOException, NoSuchAlgorithmException, InvalidKeySpecException {
    String key = new String(readFileBytes("public.key.prudential"), Charset.defaultCharset());
    String publicKeyPEM = key.replace("-----BEGIN PUBLIC KEY-----", "").replaceAll(System.lineSeparator(), "")
                                .replace("-----END PUBLIC KEY-----", "").replaceAll("\\s+", "");
    byte[] decoded = Base64.getDecoder().decode(publicKeyPEM);
    X509EncodedKeySpec spec = new X509EncodedKeySpec(decoded);
    KeyFactory keyFactory = KeyFactory.getInstance("RSA");
    return (RSAPublicKey) keyFactory.generatePublic(spec);
}
public static byte[] readFileBytes(String key) throws IOException {
    return Files.readAllBytes(Paths.get(Utils.loadPropertiesWithStaticProperty(key)));
}

When we are trying to decrypt the above encrypted data output using java callout. We are using the below xml code of java callout policy

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<JavaCallout name="Java-Callout-2">
    <Properties>
        <Property name="key-encryption">RSA-OAEP-256</Property>
        <Property name="content-encryption">A256GCM</Property>
        <Property name="debug">true</Property>
        <Property name="source">request.content</Property>
        <Property name="private-key">{private.my_private_key}</Property>
    </Properties>
    <ClassName>com.google.apigee.edgecallouts.VerifyEncryptedJwt</ClassName>
    <ResourceURL>java://something-here.jar</ResourceURL>
</JavaCallout>

While executing the API we are facing issue

ejt_error : AES/GCM/NoPadding decryption failed: Tag mismatch!

Thank You,

Lakshmi Motupalli