add decryption test

package.json

@@ -26,7 +26,10 @@
     "raknet": "^1.7.4",
     "uuid-1345": "^0.99.6"
   },
-  "devDependencies": {},
+  "devDependencies": {
+    "buffer-equal": "^1.0.0",
+    "mocha": "^2.5.3"
+  },
   "repository": {
     "type": "git",
     "url": "git+https://github.com/mhsjlw/pocket-minecraft-protocol.git"

test/decryption.js

@@ -0,0 +1,41 @@
+const crypto=require("crypto");
+const assert=require("assert");
+const bufferEqual=require("buffer-equal");
+
+// based on https://s.yawk.at/8W5U and https://confluence.yawk.at/display/PEPROTOCOL/Encryption
+describe("decryption",() => {
+  let decipher;
+  before(() => {
+
+    let secretKeyBytes = new Buffer("ZOBpyzki/M8UZv5tiBih048eYOBVPkQE3r5Fl0gmUP4=","base64");
+
+    /////
+
+    let iv = secretKeyBytes.slice(0,16);
+
+    assert(bufferEqual(iv, new Buffer("ZOBpyzki/M8UZv5tiBih0w==","base64")));
+
+
+    decipher = crypto.createDecipheriv('aes-256-cfb8', secretKeyBytes, iv);
+  });
+
+
+  it("decrypt 1",cb => {
+    let packet1Encrypted = new Buffer("4B4FCA0C2A4114155D67F8092154AAA5EF","hex");
+    decipher.once('data', packet1Decrypted => {
+      assert(bufferEqual(packet1Decrypted, new Buffer("0400000000499602D2FC2FCB233F34D5DD", "hex")));
+      cb();
+    });
+    decipher.write(packet1Encrypted);
+  });
+
+
+  it("decrypt 2",cb => {
+    let packet2Encrypted = new Buffer("DF53B9764DB48252FA1AE3AEE4","hex");
+    decipher.once('data', packet2Decrypted => {
+      assert(bufferEqual(packet2Decrypted,new Buffer("3C000000085A446D11C0C7AA5A","hex")));
+      cb();
+    });
+    decipher.write(packet2Encrypted);
+  })
+});