From fcaa3f0d73d11a49aa0ae35ffe60619a6fd28d2a Mon Sep 17 00:00:00 2001
From: Moxie Marlinspike <moxie@thoughtcrime.org>
Date: Tue, 8 Jul 2014 19:59:35 -0700
Subject: [PATCH] Simplify HKDF interface.

---
 .../main/java/org/whispersystems/libaxolotl/kdf/HKDF.java    | 3 +--
 .../main/java/org/whispersystems/libaxolotl/kdf/HKDFv2.java  | 5 -----
 .../main/java/org/whispersystems/libaxolotl/kdf/HKDFv3.java  | 5 -----
 3 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDF.java b/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDF.java
index 2301b4fbbc..d190822df0 100644
--- a/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDF.java
+++ b/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDF.java
@@ -63,7 +63,7 @@ public abstract class HKDF {
       ByteArrayOutputStream results        = new ByteArrayOutputStream();
       int                   remainingBytes = outputSize;
 
-      for (int i= getIterationStartOffset();i<iterations + getIterationEndOffset();i++) {
+      for (int i= getIterationStartOffset();i<iterations + getIterationStartOffset();i++) {
         Mac mac = Mac.getInstance("HmacSHA256");
         mac.init(new SecretKeySpec(prk, "HmacSHA256"));
 
@@ -89,6 +89,5 @@ public abstract class HKDF {
   }
 
   protected abstract int getIterationStartOffset();
-  protected abstract int getIterationEndOffset();
 
 }
diff --git a/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDFv2.java b/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDFv2.java
index 5b838f0145..86e4bf5f32 100644
--- a/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDFv2.java
+++ b/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDFv2.java
@@ -5,9 +5,4 @@ public class HKDFv2 extends HKDF {
   protected int getIterationStartOffset() {
     return 0;
   }
-
-  @Override
-  protected int getIterationEndOffset() {
-    return 0;
-  }
 }
diff --git a/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDFv3.java b/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDFv3.java
index dad6fd15b1..a1934c9058 100644
--- a/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDFv3.java
+++ b/libaxolotl/src/main/java/org/whispersystems/libaxolotl/kdf/HKDFv3.java
@@ -5,9 +5,4 @@ public class HKDFv3 extends HKDF {
   protected int getIterationStartOffset() {
     return 1;
   }
-
-  @Override
-  protected int getIterationEndOffset() {
-    return 1;
-  }
 }