EMV Cryptogram

This package helps with EMV data data extraction and processing.

It's able to

• Parse EMV Data into a TLV structure
• Encrypt and Decrypt various EMV fields

Postman Requests

This package can be used to update a transaction's emv data in a postman request.

An example request can be seen below.

Pre-requisites

The following postman variables must be set before using the script below

• scheme: The card scheme used in the transaction (must be "mastercard", "visa" or "amex")
• country: The country in which this transaction was performed
• pan: The PAN number for the transaction's card
• emv_data: The hex encoded string of the card's EMV data

const emvCryptogram = pm.require('npm:emv-cryptogram@latest');

pm.variables.set("scheme", "visa")
pm.variables.set("country", "GB")
pm.variables.set("emv_data", "<emv-data>");
pm.variables.set("pan", "<pan>");

function formatTransactionDate(transactionDate) {
  const transactionYear = transactionDate.substring(2, 4);
  const transactionMonth = transactionDate.substring(5, 7);
  const transactionDay = transactionDate.substring(8, 10);

  return transactionYear + transactionMonth + transactionDay;
}

const request = JSON.parse(pm.request.body.raw);

const transaction = new emvCryptogram.Transaction(
    request["type"],
    new emvCryptogram.Amounts(
        request["amounts"]["amount"],
        request["amounts"]["currency"],
    ),
    pm.variables.get("emv_data"),
    pm.variables.get("pan"),
    pm.variables.get("scheme"),
    pm.variables.get("country"),
    formatTransactionDate(request["transacted_at"])
)

emvCryptogram.updateEmvData(transaction);
pm.variables.set("emv_data", transaction.emvData);