Calculating the Payload-Signature

Calculating the Signature

All calls to our Cashouts APIs must contain a Payload-Signature field on the header used to ensure request integrity and to authenticate yourself since you will use your own API Signature (secret key) to generate and encrypt a hash.

It has to be created using HMAC-SHA-256 (RFC 2104) encoding and the payload is made of the entire JSON Payload sent in the body of the requests and notifications.

Use your API Signature to create the HASH

The Payload-Signature field on the header of the requests will contain the hash generated from hashing the entire JSON Payload:

Payload-Signature: HMAC256(jsonPayload)

Example:

Payload-Signature: 223a9dd4784726f1536c926da7dc69155a57612c5c3c1e1b429c367a5eee67cf

Notes

• The Payload-Signature value is case sensitive and must be sent in lower case.

• In case the jsonPayload value is empty, use an empty string instead.

• The jsonPayload should be converted to UTF-8 before hashing it to prevent Invalid Signature error when sending characters with different encodings.

​

Examples

Check the examples below on how to calculate the Payload-Signature.

Java

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.net.util.Base64;

String json_payload = "{ \"login\": \"cashout_API_Key\", \"pass\": \"cashout_API_Passphrase\",   \"external_id\": \"123456789\",  \"document_id\": \"1234567899\",  \"document_type\": \"\",   \"cashout_type\": \"BANK\", \"beneficiary_name\": \"Test User\", \"beneficiary_lastname\": \"Test User\",  \"country\": \"MX\",  \"amount\": 2000,  \"currency\": \"MXN\",  \"email\": \"[e-mail]\", \"notification_url\": \"http:\\/\\/merchant.com\\/notification\",  \"bank_code\": \"072\",\"bank_branch\": \"\",  \"bank_account\": \"1234567890\", \"account_type\": \"C\", \"address\": \"\"}";
String secretKey = "cashout_secret_key";
Mac hasher = Mac.getInstance("HmacSHA256");
hasher.init(new SecretKeySpec(secretKey.getBytes(), "HmacSHA256"));
String payload_signature = Base64.encodeBase64String(hasher.doFinal(json_payload.getBytes())).toLowerCase();

PHP

<?php
$json_payload = '{
"login": "cashout_API_Key",
"pass": "cashout_API_Passphrase",
"external_id": "123456789",
"document_id": "1234567899",
"document_type": "", 
"cashout_type": "BANK",
"beneficiary_name": "Test User",
"beneficiary_lastname": "Test User",
"country": "MX",
"amount": 2000,
"currency": "MXN",
"email": "[e-mail]",
"notification_url": "http://www.merchant.com/notification",
"bank_code": "072",
"bank_branch": "",
"bank_account": "1234567890",
"account_type": "C",
"address": ""
}';
$secretKey = "cashout_secret_key";
$payload_signature = strtolower(hash_hmac('sha256', pack('A*', $json_payload), pack('A*', $secretKey)));
?>

C#

using System;
using System.Text;
using System.Security.Cryptography;

string jsonPayload = "{ \"login\": \"cashout_API_Key\", \"pass\": \"cashout_API_Passphrase\",   \"external_id\": \"123456789\",  \"document_id\": \"1234567899\",  \"document_type\": \"\",   \"cashout_type\": \"BANK\", \"beneficiary_name\": \"Test User\", \"beneficiary_lastname\": \"Test User\",  \"country\": \"MX\",  \"amount\": 2000,  \"currency\": \"MXN\",  \"email\": \"[e-mail]\", \"notification_url\": \"http:\\/\\/www.merchant.com\\/notification\",  \"bank_code\": \"072\",\"bank_branch\": \"\",  \"bank_account\": \"1234567890\", \"account_type\": \"C\", \"address\": \"\"}";
string secretKey = "cashout_secret_key";        
byte[] keyByte = new ASCIIEncoding().GetBytes(secretKey);
byte[] jsonPayloadBytes = new ASCIIEncoding().GetBytes(jsonPayload);
byte[] hashmessage = new HMACSHA256(keyByte).ComputeHash(jsonPayloadBytes);
string payloadSignature = BitConverter.ToString(hashmessage).Replace("-", "").ToLower();