2. Request Signing

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Request Signing with HMAC

To guarantee the security and authenticity of requests to our API, we use HMAC (Hash-based Message Authentication Code) together with a private key that will be provided to you.

Suggested Code

We recommend using something similar to the following code to guide you when signing requests:

const crypto = require("crypto");

const privateKey = process.env.PRIVATE_KEY;

const signRequest = ({ apiPath, body, params }) => {
  const nonce = Date.now().toString();
  let message = "";

  if (body) {
    message = `${JSON.stringify(body)}${nonce}`;
  } else if (apiPath && params) {
    const stringParams = Object.keys(params).reduce((acc, key) => {
      if (params[key]) {
        acc[key] = String(params[key]);
      }
      return acc;
    }, {});

    const searchParams = new URLSearchParams(stringParams);
    const queryString = searchParams.toString();
    const apiPathMessage = `${apiPath}?${queryString}`;
    message = `${apiPathMessage}${nonce}`;
  }

  const hash = crypto.createHash("sha256");
  hash.update(message, "utf8");
  const messageDigest = hash.digest();

  const sign = crypto.createSign("SHA256");
  sign.update(messageDigest);
  sign.end();

  const signature = sign.sign(privateKey, "base64");
  return { signature, nonce };
};

module.exports = { signRequest };

The way a request is signed depends on the request type:

• Requests with a body (POST, PATCH, PUT): Sign the body content together with a nonce.
• Requests with query parameters (GET, DELETE): Sign the path, the queryParams, and the nonce.

Example Request to Create a Quote (POST)

When creating a quote, the signature is generated using the request body and a nonce to ensure the request is secure.

Steps to Sign a POST Request

1. Generate a nonce: A unique value based on a timestamp.
2. Create the message: Concatenate the request body with the nonce.
3. Generate the signature: Use your private key to create an HMAC signature of the message.

Message for POST: body + nonce

Example POST Request to Create a Quote

POST /quotation
Host: baseUrl
nonce: 1657891234567
signature: <generated_signature>
Content-Type: application/json

{
  "sourceCountry": "US",
  "sourceCurrency": "USD",
  "targetCountry": "VE",
  "targetCurrency": "VES",
  "amount": 1000,
  "payoutType": "BANK_TRANSFER",
  "amountType": "SOURCE"
}

In this example, the message to sign would be:

{"sourceCountry":"US","sourceCurrency":"USD","targetCountry":"VE","targetCurrency":"VES","amount":1000,"payoutType":"BANK_TRANSFER","amountType":"SOURCE"}1657891234567

Where the request body is concatenated with the nonce to create the message to sign.

Example Request to Get a Quote by ID (GET)

For GET requests, such as retrieving a specific quote by its ID, the path and nonce are signed.

Steps to Sign a GET Request

1. Generate a nonce: Use a unique timestamp for each request.
2. Create the message: Concatenate:
   • The request path
   • The ? indicator (always, even if there are no query parameters)
   • The queryParams (if any)
   • The nonce.
3. Generate the signature: Sign the message using your private key.

Message for GET: path + `?` + queryParams + nonce

Example GET Request to Get a Quote by ID

GET /quotation/12345
Host: baseUrl
nonce: 1657891234567
signature: <generated_signature>

In this example, the message to sign would be:

/quotation/12345?1657891234567

Where /quotation/12345 is the request path, ? is the query params indicator, and 1657891234567 is the nonce.

Example GET Request with Query Params

GET /balance?currency=USD&date=2024-10-01
Host: baseUrl
nonce: 1657891234567
signature: <generated_signature>

In this example, the message to sign would be:

/balance?currency=USD&date=2024-10-011657891234567

Where /balance is the path, ? is the query params indicator, currency=USD&date=2024-10-01 are the query params in alphabetical order, and 1657891234567 is the nonce.

Important:

The query parameters (queryParams) must be in alphabetical order to ensure the signature is consistent and valid. This means that if you have multiple parameters, they must be sorted alphabetically before generating the signature.