1 files changed, 38 insertions, 0 deletions
diff --git a/src/main/java/org/whispersystems/libaxolotl/groups/GroupSessionBuilder.java b/src/main/java/org/whispersystems/libaxolotl/groups/GroupSessionBuilder.java
new file mode 100644
index 00000000..8b73484b
--- /dev/null
+++ b/src/main/java/org/whispersystems/libaxolotl/groups/GroupSessionBuilder.java
@@ -0,0 +1,38 @@
+package org.whispersystems.libaxolotl.groups;
+
+import org.whispersystems.libaxolotl.ecc.ECKeyPair;
+import org.whispersystems.libaxolotl.groups.state.SenderKeyRecord;
+import org.whispersystems.libaxolotl.groups.state.SenderKeyStore;
+import org.whispersystems.libaxolotl.protocol.SenderKeyDistributionMessage;
+
+public class GroupSessionBuilder {
+
+  private final SenderKeyStore senderKeyStore;
+
+  public GroupSessionBuilder(SenderKeyStore senderKeyStore) {
+    this.senderKeyStore = senderKeyStore;
+  }
+
+  public void process(String sender, SenderKeyDistributionMessage senderKeyDistributionMessage) {
+    synchronized (GroupCipher.LOCK) {
+      SenderKeyRecord senderKeyRecord = senderKeyStore.loadSenderKey(sender);
+      senderKeyRecord.addSenderKeyState(senderKeyDistributionMessage.getId(),
+                                        senderKeyDistributionMessage.getIteration(),
+                                        senderKeyDistributionMessage.getChainKey(),
+                                        senderKeyDistributionMessage.getSignatureKey());
+      senderKeyStore.storeSenderKey(sender, senderKeyRecord);
+    }
+  }
+
+  public SenderKeyDistributionMessage process(String groupId, int keyId, int iteration,
+                                              byte[] chainKey, ECKeyPair signatureKey)
+  {
+    synchronized (GroupCipher.LOCK) {
+      SenderKeyRecord senderKeyRecord = senderKeyStore.loadSenderKey(groupId);
+      senderKeyRecord.setSenderKeyState(keyId, iteration, chainKey, signatureKey);
+      senderKeyStore.storeSenderKey(groupId, senderKeyRecord);
+
+      return new SenderKeyDistributionMessage(keyId, iteration, chainKey, signatureKey.getPublicKey());
+    }
+  }
+}