Generate Signature

The signature is required to authenticate and initiate API request for checkout. It is generated using HMAC-SHA512 encryption with a secret key and concatenated request parameters.

Implementation Example - Java

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;

public class HmacSignatureGenerator {

    public static String generateSignature(String secretKey, String concatenatedValues) {
        try {
            // Compute HMAC-SHA512
            Mac sha512HMAC = Mac.getInstance("HmacSHA512");
            SecretKeySpec keySpec = new SecretKeySpec(
                secretKey.getBytes(StandardCharsets.UTF_8),
                "HmacSHA512"
            );
            sha512HMAC.init(keySpec);

            byte[] hashBytes = sha512HMAC.doFinal(
                concatenatedValues.getBytes(StandardCharsets.UTF_8)
            );

            // Convert bytes to lowercase hex string
            StringBuilder hash = new StringBuilder();
            for (byte b : hashBytes) {
                hash.append(String.format("%02x", b));
            }
            return hash.toString();
        } catch (Exception e) {
            throw new UPGException("Error generating HMAC-SHA512 signature");
        }
    }
}

Parameters

Secret Key

The secretKey is a unique string value obtained from the My Profile section in the Merchant Portal. This key is generated automatically during merchant account creation.

Concatenated Values

The concatenatedValues is a string created by concatenating request parameter values in alphabetical order of keys, without any whitespaces.

Example Request Object:

{
  "merchantId": 7,
  "orderId": "teett",
  "merchantName": "Test Company",
  "amount": "89.99",
  "paymentMethod": "test",
  "description": "Payment for order #123",
  "merchantCustomerName": "Dummy user",
  "merchantCustomerPhoneNumber": "9800000000"
}

Alphabetically Ordered Keys: amount, description, merchantCustomerName, merchantCustomerPhoneNumber, merchantId, merchantName, orderId, paymentMethod

Concatenated String (no whitespaces):

89.99Paymentfororder#123Dummyuser9800000007TestCompanyteettTest

note

• Retrieve the secretKey from your Merchant Portal profile.
• Concatenate request parameter values in alphabetical key order without whitespaces.
• Call generateSignature(secretKey, concatenatedValues) to obtain the signature.
• Include the signature in your API request headers for checkout.