import io.jsonwebtoen.SignatureAlgorithm; 

 import javax.crypto.spec.SecretKeySpec; 

 import java.security.Key; 

 import io.jsonwebtoken.JwtBuilder; 

 import io.jsonwebtoken.Jwts; 

 import java.io.UnsupportedEncodingException; 

 public static String generateJwt(String userToken) throws UnsupportedEncodingException
 
{
 
String secretKey = ""; //This value will be given once add-on is created. Then replace the    provided value here

 long notBeforeMillis = System.currentTimeMillis(); 

 long notAfterMillis = notBeforeMillis + 300000; 

 SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.HS256; 

 byte[] apiKeySecretBytes = secretKey.getBytes();


 Key signingKey = new SecretKeySpec(apiKeySecretBytes, signatureAlgorithm.getJcaName()); 

 JwtBuilder builder = Jwts.builder().signWith(signatureAlgorithm, signingKey);
 
 String jwt = builder.claim("email_verified", true)
 .claim("not_after", notAfterMillis)
 .claim("not_before", notBeforeMillis)
 .claim("email", <user_email_address_from_user_token>).compact(); 
 
 return jwt;

}