Add example

authenticated-encryption.js

@@ -0,0 +1,42 @@
+'use strict';
+const crypto = require('crypto');
+
+// The two keys gotten from Trustpilot
+let encryptionKeyBase64 = 'XCxIAot+Tr6FVbU5fROwe2ckBEoFDcb6gwBT8022oVs=';
+let authenticationKeyBase64 = 'wNh58yFZ58H+QPomgWkgPqM3JZegQqpg39k06Q4ZvrA=';
+let domain = 'my-domain.com';
+
+// Our order to encrypt
+let order = {
+    "email":"xyz@domain.com",
+    "name":"John Smith",
+    "ref":"1234",
+    "skus":["sku1","sku2","sku3"],
+    "tags":["tag1","tag2","tag3"]
+};
+let jsonSeralizedOrder = JSON.stringify(order);
+
+// When you get the keys from Trustpilot, they are base64 encoded, so first we need to decode them
+let encryptionKey = Buffer.from(encryptionKeyBase64, 'base64');
+let authenticationKey = Buffer.from(authenticationKeyBase64, 'base64');
+
+// Generate a random initialization vector
+let iv = crypto.randomBytes(16);
+
+// Encrypt our order
+let cipher = crypto.createCipheriv('aes-256-cbc', encryptionKey, iv);
+let cipherText = Buffer.concat([cipher.update(jsonSeralizedOrder, 'utf8'), cipher.final()]);
+
+// Compute the HMAC
+let hmac = crypto.createHmac('sha256', authenticationKey).update(Buffer.concat([iv, cipherText])).digest();
+
+// Base64 encode the IV + cipherText + HMAC
+let base64Payload = Buffer.concat([iv, cipherText, hmac]).toString("base64");
+
+// URL encode to get the final payload
+let payload = encodeURIComponent(base64Payload);
+
+// The final url
+let url = 'https://www.trustpilot.com/evaluate-bgl/' + domain + '?p=' + payload;
+
+console.log(url);