1 files changed, 26 insertions, 0 deletions
diff --git a/java/src/main/java/org/whispersystems/libaxolotl/groups/ratchet/SenderChainKey.java b/java/src/main/java/org/whispersystems/libaxolotl/groups/ratchet/SenderChainKey.java
index 71375923..304c4667 100644
--- a/java/src/main/java/org/whispersystems/libaxolotl/groups/ratchet/SenderChainKey.java
+++ b/java/src/main/java/org/whispersystems/libaxolotl/groups/ratchet/SenderChainKey.java
@@ -1,3 +1,19 @@
+/**
+ * Copyright (C) 2014-2015 Open Whisper Systems
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
 package org.whispersystems.libaxolotl.groups.ratchet;
 
 import java.security.InvalidKeyException;
@@ -6,6 +22,16 @@ import java.security.NoSuchAlgorithmException;
 import javax.crypto.Mac;
 import javax.crypto.spec.SecretKeySpec;
 
+/**
+ * Each SenderKey is a "chain" of keys, each derived from the previous.
+ *
+ * At any given point in time, the state of a SenderKey can be represented
+ * as the current chain key value, along with its iteration count.  From there,
+ * subsequent iterations can be derived, as well as individual message keys from
+ * each chain key.
+ *
+ * @author Moxie Marlinspike
+ */
 public class SenderChainKey {
 
   private static final byte[] MESSAGE_KEY_SEED = {0x01};