Payment payload encryption. HELP

I am trying to integrate payment to my react-native app but the payment handler wants me to encrypt my payment data encrypt before the payment can be sent to them for processing.

Message on their site:

function encrypt(key, text) {
var forge = require(“node-forge”);
var cipher = forge.cipher.createCipher(
“3DES-ECB”,
forge.util.createBuffer(key)
);
cipher.start({ iv: “” });
cipher.update(forge.util.createBuffer(text, “utf-8”));
cipher.finish();
var encrypted = cipher.output;
return forge.util.encode64(encrypted.getBytes());
}

PLEASE IDEA OR TUTORIAL ABOUT THIS?