From 5934cb31ce9e7ecce0e2725d2510c11a6d6ed54c Mon Sep 17 00:00:00 2001
From: Felix Ableitner <me@nutomic.com>
Date: Wed, 17 Dec 2014 02:36:39 +0200
Subject: [PATCH] Reduce CryptoData size by using smaller length fields.

---
 PROTOCOL.md                                          |  6 ++----
 .../ensichat/protocol/messages/CryptoData.scala      | 12 ++++++------
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/PROTOCOL.md b/PROTOCOL.md
index e4d8de7..e1d8bdb 100644
--- a/PROTOCOL.md
+++ b/PROTOCOL.md
@@ -106,16 +106,14 @@ message.
      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                        Signature Length                       |
+    |        Signature Length       |          Key Length           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     /                                                               /
     \                   Signature (variable length)                 \
     /                                                               /
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-    |                     Encryption Key Length                     |
-    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     /                                                               /
-    \               Encryption Key (variable length)                \
+    \               Key (variable length)                \
     /                                                               /
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
diff --git a/app/src/main/scala/com/nutomic/ensichat/protocol/messages/CryptoData.scala b/app/src/main/scala/com/nutomic/ensichat/protocol/messages/CryptoData.scala
index b809570..71788eb 100644
--- a/app/src/main/scala/com/nutomic/ensichat/protocol/messages/CryptoData.scala
+++ b/app/src/main/scala/com/nutomic/ensichat/protocol/messages/CryptoData.scala
@@ -3,6 +3,7 @@ package com.nutomic.ensichat.protocol.messages
 import java.nio.ByteBuffer
 import java.util.Arrays
 
+import android.util.Log
 import com.nutomic.ensichat.protocol.BufferUtils
 
 object CryptoData {
@@ -12,11 +13,11 @@ object CryptoData {
    */
   def read(array: Array[Byte]): (CryptoData, Array[Byte]) = {
     val b = ByteBuffer.wrap(array)
-    val signatureLength = BufferUtils.getUnsignedInt(b).toInt
+    val signatureLength = BufferUtils.getUnsignedShort(b)
+    val keyLength = BufferUtils.getUnsignedShort(b)
     val signature = new Array[Byte](signatureLength)
     b.get(signature, 0, signatureLength)
 
-    val keyLength = BufferUtils.getUnsignedInt(b).toInt
     val key =
       if (keyLength != 0) {
         val key = new Array[Byte](keyLength)
@@ -46,18 +47,17 @@ case class CryptoData(Signature: Option[Array[Byte]], Key: Option[Array[Byte]])
 
   /**
    * Writes this object into a new byte array.
-   * @return
    */
   def write: Array[Byte] = {
     val b = ByteBuffer.allocate(length)
-    BufferUtils.putUnsignedInt(b, Signature.get.length)
+    BufferUtils.putUnsignedShort(b, Signature.get.length)
+    BufferUtils.putUnsignedShort(b, keyLength)
     b.put(Signature.get)
-    BufferUtils.putUnsignedInt(b, keyLength)
     if (Key.nonEmpty) b.put(Key.get)
     b.array()
   }
 
-  def length = 8 + Signature.get.length + keyLength
+  def length = 4 + Signature.get.length + keyLength
 
   private def keyLength = if (Key.isDefined) Key.get.length else 0