From 7fb4afa445b94e78b0b54f5074dda2c2a2e9467a Mon Sep 17 00:00:00 2001
From: Lee Miller <lee.miller@tutanota.com>
Date: Fri, 23 Dec 2022 22:56:18 +0200
Subject: [PATCH] Reproduce a simple encryption test, compute alternative MAC

---
 index.js | 119 +++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 85 insertions(+), 34 deletions(-)

diff --git a/index.js b/index.js
index 3d05fae..17ef472 100644
--- a/index.js
+++ b/index.js
@@ -1,40 +1,91 @@
-var messages = require('bitmessage').messages;
-var objects = require('bitmessage').objects;
-var Address = require('bitmessage').Address;
-var TcpTransport = require('bitmessage-transports').TcpTransport;
+
+// var messages = require('bitmessage').messages;
+// var objects = require('bitmessage').objects;
+// var Address = require('bitmessage').Address;
+// var TcpTransport = require('bitmessage-transports').TcpTransport;
+var crypto = require("crypto");
 var eccrypto = require("eccrypto");
 
+var assert = exports.assert = function(condition, message) {
+  if (!condition) {
+    throw new Error(message || "Assertion failed");
+  }
+};
+
 (async () => {
-  const from = Address.fromPassphrase('loremipsum1');
-  console.log('[from]', from.encode());
-  console.log('[from sign priv key]', from.signPrivateKey.toString('hex'));
-  console.log('[from version]', from.version);
-  console.log('[from stream]', from.stream);
-  console.log('[from behaviour]', from.behavior);
-  const toAddr = Address.fromPassphrase('gru');
-  console.log('[toAddr]', toAddr.encode());
-  console.log('[toAddr enc pub key]', toAddr.encPublicKey.toString('hex'));
-  console.log('[toAddr version]', toAddr.version);
-  console.log('[toAddr stream]', toAddr.stream);
-  console.log('[toAddr ripe]', toAddr.ripe);
-  const encodedMsg = await objects.msg.encodePayloadAsync({
-    ttl: 1800,
-    from: from,
-    to: toAddr,
-    message: 'hey there!',
-    subject: 'Lorem Ipsum',
-    encoding: 2,
-    friend: true,
-    skipPow: true,
-  });
-  const strippedMsg = encodedMsg.slice(8);
-  console.log('[check messages]', strippedMsg);
-  console.log('[check messages]', strippedMsg.toString('hex'));
-  var d = await objects.msg.decodePayloadAsync(encodedMsg, {
-    skipPow: true,
-    identities: toAddr,
-  });
-  console.log('[decoded]', d.message);
+    const encPublicKey = Buffer.from(
+	'0409d4e5c0ab3d25fe048c64c9da1a242c7f19417e9517cd266950d72c755713585c6178e97fe092fc897c9a1f1720d5770ae8eaad2fa8fcbd08e9324a5dde1857', 'hex'
+    );
+    const message = Buffer.from('The quick brown fox jumps over the lazy dog.');
+    const ephemPublicKey = Buffer.from(
+	'02ca00200293213dcf1388b61c2ae5cf80fee6ffffc049a2f9fe7365fe3867813ca812920020df94686c6afb565ac6149b153d61b3b287ee2c7f997c14238796c12b43a3865a', 'hex'
+    );
+    const sampleOpts = {
+	iv: Buffer.from('bddb7c2829b08038753084a2f3991681', 'hex'),
+	ephemPrivateKey: Buffer.from(
+	    '5be6facd941b76e9d3ead03029fbdb6b6e0809293f7fb197d0c51f84e96b8ba4',
+	    'hex'
+	)
+    };
+    const sampleCiphertext = '64203d5b24688e2547bba345fa139a5a1d962220d4d48a0cf3b1572c0d95b61643a6f9a0d75af7eacc1bd957147bf723';
+    const sampleMACKey = 'f83f1e9cc5d6b8448d39dc6a9d5f5b7f460e4a78e9286ee8d91ce1660a53eacd';
+    const sampleMAC = 'f2526d61b4851fb23409863826fd206165edc021368c7946571cead69046e619';
+    var mackey = await eccrypto.derive(
+	sampleOpts.ephemPrivateKey, encPublicKey
+    ).then(function(Px) {
+	var hash = crypto.createHash("sha512").update(Px).digest();
+	// var encryptionKey = hash.slice(0, 32);
+	var macKey = hash.slice(32);
+	return macKey
+    });
+    console.log('[mackey]', mackey.toString('hex'));
+
+    assert(mackey.toString('hex') == sampleMACKey, 'Bad MAC key!')
+    
+    var alt_mac = crypto.createHmac("sha256", mackey).update(
+	Buffer.concat([
+	    sampleOpts.iv, ephemPublicKey, Buffer.from(sampleCiphertext, 'hex')])
+    ).digest()
+
+    console.log('[alt mac]', alt_mac.toString('hex'));
+    
+    var encrypted = await eccrypto.encrypt(encPublicKey, message, sampleOpts);
+    console.log('[ephem pubkey]', encrypted.ephemPublicKey.toString('hex'));
+    console.log('[ciphertext]', encrypted.ciphertext.toString('hex'));
+    console.log('[mac]', encrypted.mac.toString('hex'));
+
+    assert(encrypted.ciphertext.toString('hex') == sampleCiphertext, 'Bad ciphertext!');
+    assert(encrypted.mac.toString('hex') == sampleMAC, 'Bad MAC!');
+  // const from = Address.fromPassphrase('loremipsum1');
+  // console.log('[from]', from.encode());
+  // console.log('[from sign priv key]', from.signPrivateKey.toString('hex'));
+  // console.log('[from version]', from.version);
+  // console.log('[from stream]', from.stream);
+  // console.log('[from behaviour]', from.behavior);
+  // const toAddr = Address.fromPassphrase('gru');
+  // console.log('[toAddr]', toAddr.encode());
+  // console.log('[toAddr enc pub key]', toAddr.encPublicKey.toString('hex'));
+  // console.log('[toAddr version]', toAddr.version);
+  // console.log('[toAddr stream]', toAddr.stream);
+  // console.log('[toAddr ripe]', toAddr.ripe);
+  // const encodedMsg = await objects.msg.encodePayloadAsync({
+  //   ttl: 1800,
+  //   from: from,
+  //   to: toAddr,
+  //   message: 'hey there!',
+  //   subject: 'Lorem Ipsum',
+  //   encoding: 2,
+  //   friend: true,
+  //   skipPow: true,
+  // });
+  // const strippedMsg = encodedMsg.slice(8);
+  // console.log('[check messages]', strippedMsg);
+  // console.log('[check messages]', strippedMsg.toString('hex'));
+  // var d = await objects.msg.decodePayloadAsync(encodedMsg, {
+  //   skipPow: true,
+  //   identities: toAddr,
+  // });
+  // console.log('[decoded]', d.message);
   // const encPublicKey = '04a60f6cd97ecd16768215ef059ccfbb1840b736bcdb0763872ddfeef4c417d2ec8439383ce68de9a2b30ad44e9f0e56a13fc2895a6e41f7cf3757e46181d32dd0';
   // const encPrivateKey = '2cb5ae4e8cf8c71d1221f5c6c46810b448207cacedd86cc52219c3f107048c10';
   // const dec = await objects.msg.decPayloadTest(encPrivateKey, e);