Support for an 'end session' protocol message.

1) On the push side, this message is a flag in PushMessageContent.
   Any secure message with that flag will terminate the current
   sessin.

2) On the SMS side, there is an "end session" wire type and
   the convention that a message with this wire type must be
   secure and contain the string "TERMINATE."

library/protobuf/IncomingPushMessageSignal.proto

@@ -10,7 +10,6 @@ message IncomingPushMessageSignal {
     KEY_EXCHANGE  = 2;
     PREKEY_BUNDLE = 3;
     PLAINTEXT     = 4;
-    ADVISORY      = 5;
   }
   optional Type   type         = 1;
   optional string source       = 2;
@@ -23,9 +22,9 @@ message IncomingPushMessageSignal {
 
 message PushMessageContent {
   message AttachmentPointer {
-    optional fixed64 id = 1;
+    optional fixed64 id          = 1;
-    optional string contentType = 2;
+    optional string  contentType = 2;
-    optional bytes key = 3;
+    optional bytes   key         = 3;
   }
 
   message GroupContext {
@@ -37,14 +36,19 @@ message PushMessageContent {
       ADD     = 4;
       QUIT    = 5;
     }
-    optional bytes id = 1;
+    optional bytes             id      = 1;
-    optional Type type = 2;
+    optional Type              type    = 2;
-    optional string name = 3;
+    optional string            name    = 3;
-    repeated string members = 4;
+    repeated string            members = 4;
-    optional AttachmentPointer avatar = 5;
+    optional AttachmentPointer avatar  = 5;
   }
 
-  optional string body = 1;
+  enum Flags {
+    END_SESSION = 1;
+  }
+
+  optional string            body        = 1;
   repeated AttachmentPointer attachments = 2;
-  optional GroupContext group = 3;
+  optional GroupContext      group       = 3;
+  optional uint32            flags       = 4;
 }

library/protobuf/WhisperTextProtocol.proto

@@ -23,4 +23,4 @@ message KeyExchangeMessage {
   optional bytes  baseKey      = 2;
   optional bytes  ephemeralKey = 3;
   optional bytes  identityKey  = 4;
-}
+}

library/src/org/whispersystems/textsecure/crypto/AttachmentCipher.java

@@ -31,6 +31,7 @@ import javax.crypto.spec.SecretKeySpec;
 import java.security.InvalidAlgorithmParameterException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
+import java.text.ParseException;
 import java.util.Arrays;
 
 /**
@@ -118,6 +119,8 @@ public class AttachmentCipher {
       throw new AssertionError(e);
     } catch (BadPaddingException e) {
       throw new InvalidMessageException(e);
+    } catch (ParseException e) {
+      throw new InvalidMessageException(e);
     }
   }
 

library/src/org/whispersystems/textsecure/crypto/protocol/WhisperMessageV2.java

@@ -15,6 +15,7 @@ import org.whispersystems.textsecure.util.Hex;
 import org.whispersystems.textsecure.util.Util;
 
 import java.security.NoSuchAlgorithmException;
+import java.text.ParseException;
 import java.util.Arrays;
 
 import javax.crypto.Mac;
@@ -38,7 +39,7 @@ public class WhisperMessageV2 implements CiphertextMessage {
       byte[]   mac          = messageParts[2];
 
       if (Conversions.highBitsToInt(version) != CURRENT_VERSION) {
-        throw new InvalidMessageException("Unknown version: " + Conversions.lowBitsToInt(version));
+        throw new InvalidMessageException("Unknown version: " + Conversions.highBitsToInt(version));
       }
 
       WhisperMessage whisperMessage = WhisperMessage.parseFrom(message);
@@ -59,6 +60,8 @@ public class WhisperMessageV2 implements CiphertextMessage {
       throw new InvalidMessageException(e);
     } catch (InvalidKeyException e) {
       throw new InvalidMessageException(e);
+    } catch (ParseException e) {
+      throw new InvalidMessageException(e);
     }
   }
 

library/src/org/whispersystems/textsecure/push/PushMessageProtos.java

@@ -70,7 +70,6 @@ public final class PushMessageProtos {
       KEY_EXCHANGE(2, 2),
       PREKEY_BUNDLE(3, 3),
       PLAINTEXT(4, 4),
-      ADVISORY(5, 5),
       ;
       
       public static final int UNKNOWN_VALUE = 0;
@@ -78,7 +77,6 @@ public final class PushMessageProtos {
       public static final int KEY_EXCHANGE_VALUE = 2;
       public static final int PREKEY_BUNDLE_VALUE = 3;
       public static final int PLAINTEXT_VALUE = 4;
-      public static final int ADVISORY_VALUE = 5;
       
       
       public final int getNumber() { return value; }
@@ -90,7 +88,6 @@ public final class PushMessageProtos {
           case 2: return KEY_EXCHANGE;
           case 3: return PREKEY_BUNDLE;
           case 4: return PLAINTEXT;
-          case 5: return ADVISORY;
           default: return null;
         }
       }
@@ -121,7 +118,7 @@ public final class PushMessageProtos {
       }
       
       private static final Type[] VALUES = {
-        UNKNOWN, CIPHERTEXT, KEY_EXCHANGE, PREKEY_BUNDLE, PLAINTEXT, ADVISORY, 
+        UNKNOWN, CIPHERTEXT, KEY_EXCHANGE, PREKEY_BUNDLE, PLAINTEXT, 
       };
       
       public static Type valueOf(
@@ -819,6 +816,10 @@ public final class PushMessageProtos {
     boolean hasGroup();
     org.whispersystems.textsecure.push.PushMessageProtos.PushMessageContent.GroupContext getGroup();
     org.whispersystems.textsecure.push.PushMessageProtos.PushMessageContent.GroupContextOrBuilder getGroupOrBuilder();
+    
+    // optional uint32 flags = 4;
+    boolean hasFlags();
+    int getFlags();
   }
   public static final class PushMessageContent extends
       com.google.protobuf.GeneratedMessage
@@ -848,6 +849,72 @@ public final class PushMessageProtos {
       return org.whispersystems.textsecure.push.PushMessageProtos.internal_static_textsecure_PushMessageContent_fieldAccessorTable;
     }
     
+    public enum Flags
+        implements com.google.protobuf.ProtocolMessageEnum {
+      END_SESSION(0, 1),
+      ;
+      
+      public static final int END_SESSION_VALUE = 1;
+      
+      
+      public final int getNumber() { return value; }
+      
+      public static Flags valueOf(int value) {
+        switch (value) {
+          case 1: return END_SESSION;
+          default: return null;
+        }
+      }
+      
+      public static com.google.protobuf.Internal.EnumLiteMap<Flags>
+          internalGetValueMap() {
+        return internalValueMap;
+      }
+      private static com.google.protobuf.Internal.EnumLiteMap<Flags>
+          internalValueMap =
+            new com.google.protobuf.Internal.EnumLiteMap<Flags>() {
+              public Flags findValueByNumber(int number) {
+                return Flags.valueOf(number);
+              }
+            };
+      
+      public final com.google.protobuf.Descriptors.EnumValueDescriptor
+          getValueDescriptor() {
+        return getDescriptor().getValues().get(index);
+      }
+      public final com.google.protobuf.Descriptors.EnumDescriptor
+          getDescriptorForType() {
+        return getDescriptor();
+      }
+      public static final com.google.protobuf.Descriptors.EnumDescriptor
+          getDescriptor() {
+        return org.whispersystems.textsecure.push.PushMessageProtos.PushMessageContent.getDescriptor().getEnumTypes().get(0);
+      }
+      
+      private static final Flags[] VALUES = {
+        END_SESSION, 
+      };
+      
+      public static Flags valueOf(
+          com.google.protobuf.Descriptors.EnumValueDescriptor desc) {
+        if (desc.getType() != getDescriptor()) {
+          throw new java.lang.IllegalArgumentException(
+            "EnumValueDescriptor is not for this type.");
+        }
+        return VALUES[desc.getIndex()];
+      }
+      
+      private final int index;
+      private final int value;
+      
+      private Flags(int index, int value) {
+        this.index = index;
+        this.value = value;
+      }
+      
+      // @@protoc_insertion_point(enum_scope:textsecure.PushMessageContent.Flags)
+    }
+    
     public interface AttachmentPointerOrBuilder
         extends com.google.protobuf.MessageOrBuilder {
       
@@ -2243,10 +2310,21 @@ public final class PushMessageProtos {
       return group_;
     }
     
+    // optional uint32 flags = 4;
+    public static final int FLAGS_FIELD_NUMBER = 4;
+    private int flags_;
+    public boolean hasFlags() {
+      return ((bitField0_ & 0x00000004) == 0x00000004);
+    }
+    public int getFlags() {
+      return flags_;
+    }
+    
     private void initFields() {
       body_ = "";
       attachments_ = java.util.Collections.emptyList();
       group_ = org.whispersystems.textsecure.push.PushMessageProtos.PushMessageContent.GroupContext.getDefaultInstance();
+      flags_ = 0;
     }
     private byte memoizedIsInitialized = -1;
     public final boolean isInitialized() {
@@ -2269,6 +2347,9 @@ public final class PushMessageProtos {
       if (((bitField0_ & 0x00000002) == 0x00000002)) {
         output.writeMessage(3, group_);
       }
+      if (((bitField0_ & 0x00000004) == 0x00000004)) {
+        output.writeUInt32(4, flags_);
+      }
       getUnknownFields().writeTo(output);
     }
     
@@ -2290,6 +2371,10 @@ public final class PushMessageProtos {
         size += com.google.protobuf.CodedOutputStream
           .computeMessageSize(3, group_);
       }
+      if (((bitField0_ & 0x00000004) == 0x00000004)) {
+        size += com.google.protobuf.CodedOutputStream
+          .computeUInt32Size(4, flags_);
+      }
       size += getUnknownFields().getSerializedSize();
       memoizedSerializedSize = size;
       return size;
@@ -2430,6 +2515,8 @@ public final class PushMessageProtos {
           groupBuilder_.clear();
         }
         bitField0_ = (bitField0_ & ~0x00000004);
+        flags_ = 0;
+        bitField0_ = (bitField0_ & ~0x00000008);
         return this;
       }
       
@@ -2489,6 +2576,10 @@ public final class PushMessageProtos {
         } else {
           result.group_ = groupBuilder_.build();
         }
+        if (((from_bitField0_ & 0x00000008) == 0x00000008)) {
+          to_bitField0_ |= 0x00000004;
+        }
+        result.flags_ = flags_;
         result.bitField0_ = to_bitField0_;
         onBuilt();
         return result;
@@ -2537,6 +2628,9 @@ public final class PushMessageProtos {
         if (other.hasGroup()) {
           mergeGroup(other.getGroup());
         }
+        if (other.hasFlags()) {
+          setFlags(other.getFlags());
+        }
         this.mergeUnknownFields(other.getUnknownFields());
         return this;
       }
@@ -2588,6 +2682,11 @@ public final class PushMessageProtos {
               setGroup(subBuilder.buildPartial());
               break;
             }
+            case 32: {
+              bitField0_ |= 0x00000008;
+              flags_ = input.readUInt32();
+              break;
+            }
           }
         }
       }
@@ -2906,6 +3005,27 @@ public final class PushMessageProtos {
         return groupBuilder_;
       }
       
+      // optional uint32 flags = 4;
+      private int flags_ ;
+      public boolean hasFlags() {
+        return ((bitField0_ & 0x00000008) == 0x00000008);
+      }
+      public int getFlags() {
+        return flags_;
+      }
+      public Builder setFlags(int value) {
+        bitField0_ |= 0x00000008;
+        flags_ = value;
+        onChanged();
+        return this;
+      }
+      public Builder clearFlags() {
+        bitField0_ = (bitField0_ & ~0x00000008);
+        flags_ = 0;
+        onChanged();
+        return this;
+      }
+      
       // @@protoc_insertion_point(builder_scope:textsecure.PushMessageContent)
     }
     
@@ -2947,28 +3067,28 @@ public final class PushMessageProtos {
   static {
     java.lang.String[] descriptorData = {
       "\n\037IncomingPushMessageSignal.proto\022\ntexts" +
-      "ecure\"\225\002\n\031IncomingPushMessageSignal\0228\n\004t" +
+      "ecure\"\207\002\n\031IncomingPushMessageSignal\0228\n\004t" +
       "ype\030\001 \001(\0162*.textsecure.IncomingPushMessa" +
       "geSignal.Type\022\016\n\006source\030\002 \001(\t\022\024\n\014sourceD" +
       "evice\030\007 \001(\r\022\r\n\005relay\030\003 \001(\t\022\021\n\ttimestamp\030" +
-      "\005 \001(\004\022\017\n\007message\030\006 \001(\014\"e\n\004Type\022\013\n\007UNKNOW" +
+      "\005 \001(\004\022\017\n\007message\030\006 \001(\014\"W\n\004Type\022\013\n\007UNKNOW" +
       "N\020\000\022\016\n\nCIPHERTEXT\020\001\022\020\n\014KEY_EXCHANGE\020\002\022\021\n" +
-      "\rPREKEY_BUNDLE\020\003\022\r\n\tPLAINTEXT\020\004\022\014\n\010ADVIS" +
+      "\rPREKEY_BUNDLE\020\003\022\r\n\tPLAINTEXT\020\004\"\234\004\n\022Push" +
-      "ORY\020\005\"\363\003\n\022PushMessageContent\022\014\n\004body\030\001 \001" +
+      "MessageContent\022\014\n\004body\030\001 \001(\t\022E\n\013attachme" +
-      "(\t\022E\n\013attachments\030\002 \003(\01320.textsecure.Pus",
+      "nts\030\002 \003(\01320.textsecure.PushMessageConten",
-      "hMessageContent.AttachmentPointer\022:\n\005gro" +
+      "t.AttachmentPointer\022:\n\005group\030\003 \001(\0132+.tex" +
-      "up\030\003 \001(\0132+.textsecure.PushMessageContent" +
+      "tsecure.PushMessageContent.GroupContext\022" +
-      ".GroupContext\032A\n\021AttachmentPointer\022\n\n\002id" +
+      "\r\n\005flags\030\004 \001(\r\032A\n\021AttachmentPointer\022\n\n\002i" +
-      "\030\001 \001(\006\022\023\n\013contentType\030\002 \001(\t\022\013\n\003key\030\003 \001(\014" +
+      "d\030\001 \001(\006\022\023\n\013contentType\030\002 \001(\t\022\013\n\003key\030\003 \001(" +
-      "\032\210\002\n\014GroupContext\022\n\n\002id\030\001 \001(\014\022>\n\004type\030\002 " +
+      "\014\032\210\002\n\014GroupContext\022\n\n\002id\030\001 \001(\014\022>\n\004type\030\002" +
-      "\001(\01620.textsecure.PushMessageContent.Grou" +
+      " \001(\01620.textsecure.PushMessageContent.Gro" +
-      "pContext.Type\022\014\n\004name\030\003 \001(\t\022\017\n\007members\030\004" +
+      "upContext.Type\022\014\n\004name\030\003 \001(\t\022\017\n\007members\030" +
-      " \003(\t\022@\n\006avatar\030\005 \001(\01320.textsecure.PushMe" +
+      "\004 \003(\t\022@\n\006avatar\030\005 \001(\01320.textsecure.PushM" +
-      "ssageContent.AttachmentPointer\"K\n\004Type\022\013" +
+      "essageContent.AttachmentPointer\"K\n\004Type\022" +
-      "\n\007UNKNOWN\020\000\022\n\n\006CREATE\020\001\022\n\n\006MODIFY\020\002\022\013\n\007D",
+      "\013\n\007UNKNOWN\020\000\022\n\n\006CREATE\020\001\022\n\n\006MODIFY\020\002\022\013\n\007",
-      "ELIVER\020\003\022\007\n\003ADD\020\004\022\010\n\004QUIT\020\005B7\n\"org.whisp" +
+      "DELIVER\020\003\022\007\n\003ADD\020\004\022\010\n\004QUIT\020\005\"\030\n\005Flags\022\017\n" +
-      "ersystems.textsecure.pushB\021PushMessagePr" +
+      "\013END_SESSION\020\001B7\n\"org.whispersystems.tex" +
-      "otos"
+      "tsecure.pushB\021PushMessageProtos"
     };
     com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner assigner =
       new com.google.protobuf.Descriptors.FileDescriptor.InternalDescriptorAssigner() {
@@ -2988,7 +3108,7 @@ public final class PushMessageProtos {
           internal_static_textsecure_PushMessageContent_fieldAccessorTable = new
             com.google.protobuf.GeneratedMessage.FieldAccessorTable(
               internal_static_textsecure_PushMessageContent_descriptor,
-              new java.lang.String[] { "Body", "Attachments", "Group", },
+              new java.lang.String[] { "Body", "Attachments", "Group", "Flags", },
               org.whispersystems.textsecure.push.PushMessageProtos.PushMessageContent.class,
               org.whispersystems.textsecure.push.PushMessageProtos.PushMessageContent.Builder.class);
           internal_static_textsecure_PushMessageContent_AttachmentPointer_descriptor =

library/src/org/whispersystems/textsecure/util/Util.java

@@ -13,6 +13,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
+import java.text.ParseException;
 import java.util.Collection;
 import java.util.LinkedList;
 import java.util.List;
@@ -45,7 +46,15 @@ public class Util {
     return parts;
   }
 
-  public static byte[][] split(byte[] input, int firstLength, int secondLength, int thirdLength) {
+  public static byte[][] split(byte[] input, int firstLength, int secondLength, int thirdLength)
+      throws ParseException
+  {
+    if (input == null || firstLength < 0 || secondLength < 0 || thirdLength < 0 ||
+        input.length < firstLength + secondLength + thirdLength)
+    {
+      throw new ParseException("Input too small: " + (input == null ? null : Hex.toString(input)), 0);
+    }
+
     byte[][] parts = new byte[3][];
 
     parts[0] = new byte[firstLength];

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -80,6 +80,7 @@ import org.thoughtcrime.securesms.recipients.Recipients;
 import org.thoughtcrime.securesms.service.KeyCachingService;
 import org.thoughtcrime.securesms.sms.MessageSender;
 import org.thoughtcrime.securesms.sms.OutgoingEncryptedMessage;
+import org.thoughtcrime.securesms.sms.OutgoingEndSessionMessage;
 import org.thoughtcrime.securesms.sms.OutgoingTextMessage;
 import org.thoughtcrime.securesms.util.ActionBarUtil;
 import org.thoughtcrime.securesms.util.BitmapDecodingException;
@@ -93,7 +94,9 @@ import org.thoughtcrime.securesms.util.TextSecurePreferences;
 import org.whispersystems.textsecure.crypto.InvalidMessageException;
 import org.whispersystems.textsecure.crypto.MasterCipher;
 import org.whispersystems.textsecure.crypto.MasterSecret;
+import org.whispersystems.textsecure.storage.RecipientDevice;
 import org.whispersystems.textsecure.storage.Session;
+import org.whispersystems.textsecure.storage.SessionRecordV2;
 import org.whispersystems.textsecure.util.Util;
 
 import java.io.IOException;
@@ -368,9 +371,23 @@ public class ConversationActivity extends PassphraseRequiredSherlockFragmentActi
       @Override
       public void onClick(DialogInterface dialog, int which) {
         if (isSingleConversation()) {
-          Session.abortSessionFor(ConversationActivity.this, getRecipients().getPrimaryRecipient());
+          ConversationActivity self      = ConversationActivity.this;
-          initializeSecurity();
+          Recipient            recipient = getRecipients().getPrimaryRecipient();
-          initializeTitleBar();
+
+          if (SessionRecordV2.hasSession(self, masterSecret,
+                                         recipient.getRecipientId(),
+                                         RecipientDevice.DEFAULT_DEVICE_ID))
+          {
+            OutgoingEndSessionMessage endSessionMessage =
+                new OutgoingEndSessionMessage(new OutgoingTextMessage(getRecipients(), "TERMINATE"));
+
+            long allocatedThreadId = MessageSender.send(self, masterSecret,
+                                                        endSessionMessage, threadId);
+
+            sendComplete(recipients, allocatedThreadId, allocatedThreadId != self.threadId);
+          } else {
+            Session.abortSessionFor(self, recipient);
+          }
         }
       }
     });

src/org/thoughtcrime/securesms/ReceiveKeyActivity.java

@@ -236,7 +236,7 @@ public class ReceiveKeyActivity extends Activity {
 
               DecryptingQueue.scheduleDecryption(ReceiveKeyActivity.this, masterSecret, messageId,
                                                  threadId, recipient.getNumber(), recipientDeviceId,
-                                                 messageBody, true, false);
+                                                 messageBody, true, false, false);
             } catch (InvalidKeyIdException e) {
               Log.w("ReceiveKeyActivity", e);
               DatabaseFactory.getEncryptingSmsDatabase(ReceiveKeyActivity.this)

src/org/thoughtcrime/securesms/crypto/DecryptingQueue.java

@@ -81,11 +81,12 @@ public class DecryptingQueue {
 
   public static void scheduleDecryption(Context context, MasterSecret masterSecret,
                                         long messageId, long threadId, String originator, int deviceId,
-                                        String body, boolean isSecureMessage, boolean isKeyExchange)
+                                        String body, boolean isSecureMessage, boolean isKeyExchange,
+                                        boolean isEndSession)
   {
     DecryptionWorkItem runnable = new DecryptionWorkItem(context, masterSecret, messageId, threadId,
                                                          originator, deviceId, body,
-                                                         isSecureMessage, isKeyExchange);
+                                                         isSecureMessage, isKeyExchange, isEndSession);
     executor.execute(runnable);
   }
 
@@ -167,10 +168,11 @@ public class DecryptingQueue {
     int originatorDeviceId  = record.getRecipientDeviceId();
     boolean isSecureMessage = record.isSecure();
     boolean isKeyExchange   = record.isKeyExchange();
+    boolean isEndSession    = record.isEndSession();
 
     scheduleDecryption(context, masterSecret, messageId,  threadId,
                        originator, originatorDeviceId, body,
-                       isSecureMessage, isKeyExchange);
+                       isSecureMessage, isKeyExchange, isEndSession);
   }
 
   private static class PushDecryptionWorkItem implements Runnable {
@@ -332,10 +334,11 @@ public class DecryptingQueue {
     private final int          deviceId;
     private final boolean      isSecureMessage;
     private final boolean      isKeyExchange;
+    private final boolean      isEndSession;
 
     public DecryptionWorkItem(Context context, MasterSecret masterSecret, long messageId, long threadId,
                               String originator, int deviceId, String body, boolean isSecureMessage,
-                              boolean isKeyExchange)
+                              boolean isKeyExchange, boolean isEndSession)
     {
       this.context         = context;
       this.messageId       = messageId;
@@ -346,6 +349,7 @@ public class DecryptingQueue {
       this.deviceId        = deviceId;
       this.isSecureMessage = isSecureMessage;
       this.isKeyExchange   = isKeyExchange;
+      this.isEndSession    = isEndSession;
     }
 
     private void handleRemoteAsymmetricEncrypt() {
@@ -368,6 +372,13 @@ public class DecryptingQueue {
         byte[]              paddedPlaintext   = sessionCipher.decrypt(decodedCiphertext);
 
         plaintextBody = new String(transportDetails.getStrippedPaddingMessageBody(paddedPlaintext));
+
+        if (isEndSession &&
+            "TERMINATE".equals(plaintextBody) &&
+            SessionRecordV2.hasSession(context, masterSecret, recipientDevice))
+        {
+          Session.abortSessionFor(context, recipient);
+        }
       } catch (InvalidMessageException e) {
         Log.w("DecryptionQueue", e);
         database.markAsDecryptFailed(messageId);
@@ -441,7 +452,7 @@ public class DecryptingQueue {
 
     @Override
     public void run() {
-      if (isSecureMessage) {
+      if (isSecureMessage || isEndSession) {
         handleRemoteAsymmetricEncrypt();
       } else {
         handleLocalAsymmetricEncrypt();

src/org/thoughtcrime/securesms/crypto/KeyExchangeProcessor.java

@@ -18,10 +18,12 @@
 package org.thoughtcrime.securesms.crypto;
 
 import android.content.Context;
+import android.content.Intent;
 
 import org.thoughtcrime.securesms.crypto.protocol.KeyExchangeMessage;
 import org.thoughtcrime.securesms.recipients.Recipient;
 import org.thoughtcrime.securesms.recipients.RecipientFactory;
+import org.thoughtcrime.securesms.service.KeyCachingService;
 import org.whispersystems.textsecure.crypto.InvalidMessageException;
 import org.whispersystems.textsecure.crypto.MasterSecret;
 import org.whispersystems.textsecure.storage.RecipientDevice;
@@ -45,4 +47,12 @@ public abstract class KeyExchangeProcessor {
       return new KeyExchangeProcessorV2(context, masterSecret, recipientDevice);
     }
   }
+
+  public static void broadcastSecurityUpdateEvent(Context context, long threadId) {
+    Intent intent = new Intent(SECURITY_UPDATE_EVENT);
+    intent.putExtra("thread_id", threadId);
+    intent.setPackage(context.getPackageName());
+    context.sendBroadcast(intent, KeyCachingService.KEY_PERMISSION);
+  }
+
 }

src/org/thoughtcrime/securesms/crypto/KeyExchangeProcessorV1.java

@@ -1,7 +1,6 @@
 package org.thoughtcrime.securesms.crypto;
 
 import android.content.Context;
-import android.content.Intent;
 import android.util.Log;
 
 import org.thoughtcrime.securesms.crypto.protocol.KeyExchangeMessage;
@@ -9,7 +8,6 @@ import org.thoughtcrime.securesms.crypto.protocol.KeyExchangeMessageV1;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.recipients.Recipient;
 import org.thoughtcrime.securesms.recipients.RecipientFactory;
-import org.thoughtcrime.securesms.service.KeyCachingService;
 import org.thoughtcrime.securesms.sms.MessageSender;
 import org.thoughtcrime.securesms.sms.OutgoingKeyExchangeMessage;
 import org.whispersystems.textsecure.crypto.IdentityKey;
@@ -129,13 +127,6 @@ public class KeyExchangeProcessorV1 extends KeyExchangeProcessor {
     broadcastSecurityUpdateEvent(context, threadId);
   }
 
-  private static void broadcastSecurityUpdateEvent(Context context, long threadId) {
-    Intent intent = new Intent(SECURITY_UPDATE_EVENT);
-    intent.putExtra("thread_id", threadId);
-    intent.setPackage(context.getPackageName());
-    context.sendBroadcast(intent, KeyCachingService.KEY_PERMISSION);
-  }
-
   public LocalKeyRecord initializeRecordFor(Context context,
                                             MasterSecret masterSecret,
                                             CanonicalRecipient recipient)

src/org/thoughtcrime/securesms/crypto/KeyExchangeProcessorV2.java

@@ -1,7 +1,6 @@
 package org.thoughtcrime.securesms.crypto;
 
 import android.content.Context;
-import android.content.Intent;
 import android.util.Log;
 
 import org.thoughtcrime.securesms.crypto.protocol.KeyExchangeMessage;
@@ -9,7 +8,6 @@ import org.thoughtcrime.securesms.crypto.protocol.KeyExchangeMessageV2;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.recipients.Recipient;
 import org.thoughtcrime.securesms.recipients.RecipientFactory;
-import org.thoughtcrime.securesms.service.KeyCachingService;
 import org.thoughtcrime.securesms.sms.MessageSender;
 import org.thoughtcrime.securesms.sms.OutgoingKeyExchangeMessage;
 import org.thoughtcrime.securesms.util.TextSecurePreferences;
@@ -230,11 +228,4 @@ public class KeyExchangeProcessorV2 extends KeyExchangeProcessor {
     }
   }
 
-  private static void broadcastSecurityUpdateEvent(Context context, long threadId) {
-    Intent intent = new Intent(KeyExchangeProcessorV1.SECURITY_UPDATE_EVENT);
-    intent.putExtra("thread_id", threadId);
-    intent.setPackage(context.getPackageName());
-    context.sendBroadcast(intent, KeyCachingService.KEY_PERMISSION);
-  }
-
 }

src/org/thoughtcrime/securesms/database/EncryptingSmsDatabase.java

@@ -73,7 +73,7 @@ public class EncryptingSmsDatabase extends SmsDatabase {
   {
     long type = Types.BASE_INBOX_TYPE;
 
-    if (!message.isSecureMessage()) {
+    if (!message.isSecureMessage() && !message.isEndSession()) {
       type |= Types.ENCRYPTION_SYMMETRIC_BIT;
       message = message.withMessageBody(getEncryptedBody(masterSecret, message.getMessageBody()));
     }

src/org/thoughtcrime/securesms/database/MmsSmsColumns.java

@@ -39,6 +39,7 @@ public interface MmsSmsColumns {
 
     // Secure Message Information
     protected static final long SECURE_MESSAGE_BIT = 0x800000;
+    protected static final long END_SESSION_BIT    = 0x400000;
 
     // Encrypted Storage Information
     protected static final long ENCRYPTION_MASK                  = 0xFF000000;
@@ -75,6 +76,10 @@ public interface MmsSmsColumns {
       return (type & SECURE_MESSAGE_BIT) != 0;
     }
 
+    public static boolean isEndSessionType(long type) {
+      return (type & END_SESSION_BIT) != 0;
+    }
+
     public static boolean isKeyExchangeType(long type) {
       return (type & KEY_EXCHANGE_BIT) != 0;
     }

src/org/thoughtcrime/securesms/database/SmsDatabase.java

@@ -256,6 +256,10 @@ public class SmsDatabase extends Database implements MmsSmsColumns {
     } else if (message.isSecureMessage()) {
       type |= Types.SECURE_MESSAGE_BIT;
       type |= Types.ENCRYPTION_REMOTE_BIT;
+    } else if (message.isEndSession()) {
+      type |= Types.END_SESSION_BIT;
+      type |= Types.SECURE_MESSAGE_BIT;
+      type |= Types.ENCRYPTION_REMOTE_BIT;
     }
 
     Recipients recipients;
@@ -328,6 +332,7 @@ public class SmsDatabase extends Database implements MmsSmsColumns {
   protected List<Long> insertMessageOutbox(long threadId, OutgoingTextMessage message, long type) {
     if      (message.isKeyExchange())   type |= Types.KEY_EXCHANGE_BIT;
     else if (message.isSecureMessage()) type |= Types.SECURE_MESSAGE_BIT;
+    else if (message.isEndSession())    type |= Types.END_SESSION_BIT;
 
     long date             = System.currentTimeMillis();
     List<Long> messageIds = new LinkedList<Long>();

src/org/thoughtcrime/securesms/database/model/DisplayRecord.java

@@ -84,6 +84,10 @@ public abstract class DisplayRecord {
     return SmsDatabase.Types.isKeyExchangeType(type);
   }
 
+  public boolean isEndSession() {
+    return SmsDatabase.Types.isEndSessionType(type);
+  }
+
   public int getGroupAction() {
     return groupAction;
   }

src/org/thoughtcrime/securesms/database/model/SmsMessageRecord.java

@@ -79,6 +79,9 @@ public class SmsMessageRecord extends MessageRecord {
       return emphasisAdded(context.getString(R.string.MessageDisplayHelper_message_encrypted_for_non_existing_session));
     } else if (!getBody().isPlaintext()) {
       return emphasisAdded(context.getString(R.string.MessageNotifier_encrypted_message));
+    } else if (SmsDatabase.Types.isEndSessionType(type)) {
+      // TODO jake is going to fix this up
+      return new SpannableString("Session closed!");
     } else if (isOutgoing() && Tag.isTagged(getBody().getBody())) {
       return new SpannableString(Tag.stripTag(getBody().getBody()));
     } else {

src/org/thoughtcrime/securesms/database/model/ThreadRecord.java

@@ -78,6 +78,9 @@ public class ThreadRecord extends DisplayRecord {
       return emphasisAdded(context.getString(R.string.MessageDisplayHelper_message_encrypted_for_non_existing_session));
     } else if (!getBody().isPlaintext()) {
       return emphasisAdded(context.getString(R.string.MessageNotifier_encrypted_message));
+    } else if (SmsDatabase.Types.isEndSessionType(type)) {
+      // TODO jake is going to fix this up
+      return emphasisAdded("Session closed!");
     } else {
       if (Util.isEmpty(getBody().getBody())) {
         return new SpannableString(context.getString(R.string.MessageNotifier_no_subject));

src/org/thoughtcrime/securesms/protocol/EndSessionWirePrefix.java

@@ -0,0 +1,8 @@
+package org.thoughtcrime.securesms.protocol;
+
+public class EndSessionWirePrefix extends WirePrefix {
+  @Override
+  public String calculatePrefix(String message) {
+    return super.calculateEndSessionPrefix(message);
+  }
+}

src/org/thoughtcrime/securesms/protocol/WirePrefix.java

@@ -51,6 +51,10 @@ public abstract class WirePrefix {
     return verifyPrefix("?TSP", message);
   }
 
+  public static boolean isEndSession(String message) {
+    return verifyPrefix("?TSE", message);
+  }
+
   public static String calculateKeyExchangePrefix(String message) {
     return calculatePrefix(("?TSK" + message).getBytes(), PREFIX_BYTES);
   }
@@ -63,6 +67,10 @@ public abstract class WirePrefix {
     return calculatePrefix(("?TSP" + message).getBytes(), PREFIX_BYTES);
   }
 
+  public static String calculateEndSessionPrefix(String message) {
+    return calculatePrefix(("?TSE" + message).getBytes(), PREFIX_BYTES);
+  }
+
   private static boolean verifyPrefix(String prefixType, String message) {
     if (message.length() <= PREFIX_SIZE)
       return false;

src/org/thoughtcrime/securesms/service/PushReceiver.java

@@ -8,6 +8,7 @@ import android.util.Pair;
 import com.google.protobuf.InvalidProtocolBufferException;
 
 import org.thoughtcrime.securesms.crypto.DecryptingQueue;
+import org.thoughtcrime.securesms.crypto.KeyExchangeProcessor;
 import org.thoughtcrime.securesms.crypto.KeyExchangeProcessorV2;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.database.EncryptingSmsDatabase;
@@ -20,6 +21,7 @@ import org.thoughtcrime.securesms.recipients.RecipientFactory;
 import org.thoughtcrime.securesms.recipients.RecipientFormattingException;
 import org.thoughtcrime.securesms.recipients.Recipients;
 import org.thoughtcrime.securesms.sms.IncomingEncryptedMessage;
+import org.thoughtcrime.securesms.sms.IncomingEndSessionMessage;
 import org.thoughtcrime.securesms.sms.IncomingKeyExchangeMessage;
 import org.thoughtcrime.securesms.sms.IncomingPreKeyBundleMessage;
 import org.thoughtcrime.securesms.sms.IncomingTextMessage;
@@ -34,6 +36,7 @@ import org.whispersystems.textsecure.push.IncomingPushMessage;
 import org.whispersystems.textsecure.push.PushMessageProtos.PushMessageContent;
 import org.whispersystems.textsecure.storage.InvalidKeyIdException;
 import org.whispersystems.textsecure.storage.RecipientDevice;
+import org.whispersystems.textsecure.storage.Session;
 
 import ws.com.google.android.mms.MmsException;
 
@@ -150,7 +153,10 @@ public class PushReceiver {
     try {
       PushMessageContent messageContent = PushMessageContent.parseFrom(message.getBody());
 
-      if (messageContent.hasGroup()) {
+      if (secure && (messageContent.getFlags() & PushMessageContent.Flags.END_SESSION_VALUE) != 0) {
+        Log.w("PushReceiver", "Received end session message...");
+        handleEndSessionMessage(masterSecret, message, messageContent);
+      } else if (messageContent.hasGroup()) {
         Log.w("PushReceiver", "Received push group message...");
         handleReceivedGroupMessage(masterSecret, message, messageContent, secure);
       } else if (messageContent.getAttachmentsCount() > 0) {
@@ -222,6 +228,27 @@ public class PushReceiver {
     }
   }
 
+  private void handleEndSessionMessage(MasterSecret masterSecret,
+                                       IncomingPushMessage message,
+                                       PushMessageContent messageContent)
+  {
+    try {
+      Recipient                 recipient                 = RecipientFactory.getRecipientsFromString(context, message.getSource(), true).getPrimaryRecipient();
+      IncomingTextMessage       incomingTextMessage       = new IncomingTextMessage(message, "", null);
+      IncomingEndSessionMessage incomingEndSessionMessage = new IncomingEndSessionMessage(incomingTextMessage);
+
+      EncryptingSmsDatabase database = DatabaseFactory.getEncryptingSmsDatabase(context);
+
+      Pair<Long, Long> messageAndThreadId = database.insertMessageInbox(masterSecret, incomingEndSessionMessage);
+      database.updateMessageBody(masterSecret, messageAndThreadId.first, messageContent.getBody());
+
+      Session.abortSessionFor(context, recipient);
+      KeyExchangeProcessor.broadcastSecurityUpdateEvent(context, messageAndThreadId.second);
+    } catch (RecipientFormattingException e) {
+      Log.w("PushReceiver", e);
+    }
+  }
+
   private void handleReceivedMediaMessage(MasterSecret masterSecret,
                                           IncomingPushMessage message,
                                           PushMessageContent messageContent,

src/org/thoughtcrime/securesms/service/SmsReceiver.java

@@ -68,7 +68,8 @@ public class SmsReceiver {
 
     if (WirePrefix.isEncryptedMessage(message.getMessageBody()) ||
         WirePrefix.isKeyExchange(message.getMessageBody())      ||
-        WirePrefix.isPreKeyBundle(message.getMessageBody()))
+        WirePrefix.isPreKeyBundle(message.getMessageBody())     ||
+        WirePrefix.isEndSession(message.getMessageBody()))
     {
       return multipartMessageHandler.processPotentialMultipartMessage(message);
     } else {
@@ -85,7 +86,7 @@ public class SmsReceiver {
                                          messageAndThreadId.second,
                                          message.getSender(), message.getSenderDeviceId(),
                                          message.getMessageBody(), message.isSecureMessage(),
-                                         message.isKeyExchange());
+                                         message.isKeyExchange(), message.isEndSession());
     }
 
     return messageAndThreadId;
@@ -197,10 +198,13 @@ public class SmsReceiver {
     if      (message.isSecureMessage()) return storeSecureMessage(masterSecret, message);
     else if (message.isPreKeyBundle())  return storePreKeyWhisperMessage(masterSecret, (IncomingPreKeyBundleMessage) message);
     else if (message.isKeyExchange())   return storeKeyExchangeMessage(masterSecret, (IncomingKeyExchangeMessage) message);
+    else if (message.isEndSession())    return storeSecureMessage(masterSecret, message);
     else                                return storeStandardMessage(masterSecret, message);
   }
 
   private void handleReceiveMessage(MasterSecret masterSecret, Intent intent) {
+    if (intent.getExtras() == null) return;
+
     List<IncomingTextMessage> messagesList = intent.getExtras().getParcelableArrayList("text_messages");
     IncomingTextMessage       message      = assembleMessageFragments(messagesList);
 

src/org/thoughtcrime/securesms/service/SmsSender.java

@@ -21,13 +21,16 @@ import android.app.AlarmManager;
 import android.app.PendingIntent;
 import android.content.Context;
 import android.content.Intent;
+import android.database.Cursor;
 import android.telephony.SmsManager;
 import android.telephony.SmsMessage;
 import android.util.Log;
 
 import org.thoughtcrime.securesms.R;
+import org.thoughtcrime.securesms.crypto.KeyExchangeProcessor;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.database.EncryptingSmsDatabase;
+import org.thoughtcrime.securesms.database.SmsDatabase;
 import org.thoughtcrime.securesms.database.model.SmsMessageRecord;
 import org.thoughtcrime.securesms.notifications.MessageNotifier;
 import org.thoughtcrime.securesms.recipients.Recipients;
@@ -38,6 +41,7 @@ import org.thoughtcrime.securesms.transport.UndeliverableMessageException;
 import org.thoughtcrime.securesms.transport.UniversalTransport;
 import org.thoughtcrime.securesms.transport.UntrustedIdentityException;
 import org.whispersystems.textsecure.crypto.MasterSecret;
+import org.whispersystems.textsecure.storage.Session;
 
 public class SmsSender {
 
@@ -109,10 +113,22 @@ public class SmsSender {
     Log.w("SMSReceiverService", "Running sent callback: " + messageId);
 
     if (result == Activity.RESULT_OK) {
-      DatabaseFactory.getSmsDatabase(context).markAsSent(messageId);
+      SmsDatabase        database = DatabaseFactory.getSmsDatabase(context);
+      Cursor             cursor   = database.getMessage(messageId);
+      SmsDatabase.Reader reader   = database.readerFor(cursor);
+
+      database.markAsSent(messageId);
 
       if (upgraded) {
-        DatabaseFactory.getSmsDatabase(context).markAsSecure(messageId);
+        database.markAsSecure(messageId);
+      }
+
+      SmsMessageRecord record = reader.getNext();
+
+      if (record != null && record.isEndSession()) {
+        Log.w("SmsSender", "Ending session...");
+        Session.abortSessionFor(context, record.getIndividualRecipient());
+        KeyExchangeProcessor.broadcastSecurityUpdateEvent(context, record.getThreadId());
       }
 
       unregisterForRadioChanges();
@@ -161,4 +177,5 @@ public class SmsSender {
                                                  null, context, SendReceiveService.class),
                                       PendingIntent.FLAG_UPDATE_CURRENT));
   }
+
 }

src/org/thoughtcrime/securesms/sms/IncomingEndSessionMessage.java

@@ -0,0 +1,22 @@
+package org.thoughtcrime.securesms.sms;
+
+public class IncomingEndSessionMessage extends IncomingTextMessage {
+
+  public IncomingEndSessionMessage(IncomingTextMessage base) {
+    this(base, base.getMessageBody());
+  }
+
+  public IncomingEndSessionMessage(IncomingTextMessage base, String newBody) {
+    super(base, newBody);
+  }
+
+  @Override
+  public IncomingEndSessionMessage withMessageBody(String messageBody) {
+    return new IncomingEndSessionMessage(this, messageBody);
+  }
+
+  @Override
+  public boolean isEndSession() {
+    return true;
+  }
+}

src/org/thoughtcrime/securesms/sms/IncomingTextMessage.java

@@ -216,6 +216,10 @@ public class IncomingTextMessage implements Parcelable {
     return false;
   }
 
+  public boolean isEndSession() {
+    return false;
+  }
+
   public boolean isIdentityUpdate() {
     return false;
   }

src/org/thoughtcrime/securesms/sms/MultipartSmsMessageHandler.java

@@ -71,6 +71,8 @@ public class MultipartSmsMessageHandler {
       return new IncomingKeyExchangeMessage(message.getBaseMessage(), strippedMessage);
     } else if (message.getWireType() == MultipartSmsTransportMessage.WIRETYPE_PREKEY) {
       return new IncomingPreKeyBundleMessage(message.getBaseMessage(), strippedMessage);
+    } else if (message.getWireType() == MultipartSmsTransportMessage.WIRETYPE_END_SESSION) {
+      return new IncomingEndSessionMessage(message.getBaseMessage(), strippedMessage);
     } else {
       return new IncomingEncryptedMessage(message.getBaseMessage(), strippedMessage);
     }

src/org/thoughtcrime/securesms/sms/MultipartSmsTransportMessage.java

@@ -2,12 +2,14 @@ package org.thoughtcrime.securesms.sms;
 
 import android.util.Log;
 
+import org.thoughtcrime.securesms.protocol.EndSessionWirePrefix;
 import org.thoughtcrime.securesms.protocol.KeyExchangeWirePrefix;
 import org.thoughtcrime.securesms.protocol.PrekeyBundleWirePrefix;
 import org.thoughtcrime.securesms.protocol.SecureMessageWirePrefix;
 import org.thoughtcrime.securesms.protocol.WirePrefix;
 import org.whispersystems.textsecure.util.Base64;
 import org.whispersystems.textsecure.util.Conversions;
+import org.whispersystems.textsecure.util.Hex;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -21,9 +23,10 @@ public class MultipartSmsTransportMessage {
   public static final int MULTI_MESSAGE_MULTIPART_OVERHEAD       = 3;
   public static final int FIRST_MULTI_MESSAGE_MULTIPART_OVERHEAD = 2;
 
-  public static final int WIRETYPE_SECURE = 1;
+  public static final int WIRETYPE_SECURE      = 1;
-  public static final int WIRETYPE_KEY    = 2;
+  public static final int WIRETYPE_KEY         = 2;
-  public static final int WIRETYPE_PREKEY = 3;
+  public static final int WIRETYPE_PREKEY      = 3;
+  public static final int WIRETYPE_END_SESSION = 4;
 
   private static final int VERSION_OFFSET    = 0;
   private static final int MULTIPART_OFFSET  = 1;
@@ -39,6 +42,7 @@ public class MultipartSmsTransportMessage {
 
     if      (WirePrefix.isEncryptedMessage(message.getMessageBody())) wireType = WIRETYPE_SECURE;
     else if (WirePrefix.isPreKeyBundle(message.getMessageBody()))     wireType = WIRETYPE_PREKEY;
+    else if (WirePrefix.isEndSession(message.getMessageBody()))       wireType = WIRETYPE_END_SESSION;
     else                                                              wireType = WIRETYPE_KEY;
 
     Log.w(TAG, "Decoded message with version: " + getCurrentVersion());
@@ -158,6 +162,7 @@ public class MultipartSmsTransportMessage {
 
       if      (message.isKeyExchange())  prefix = new KeyExchangeWirePrefix();
       else if (message.isPreKeyBundle()) prefix = new PrekeyBundleWirePrefix();
+      else if (message.isEndSession())   prefix = new EndSessionWirePrefix();
       else                               prefix = new SecureMessageWirePrefix();
 
       if (count == 1) return getSingleEncoded(decoded, prefix);

src/org/thoughtcrime/securesms/sms/OutgoingEndSessionMessage.java

@@ -0,0 +1,22 @@
+package org.thoughtcrime.securesms.sms;
+
+public class OutgoingEndSessionMessage extends OutgoingTextMessage {
+
+  public OutgoingEndSessionMessage(OutgoingTextMessage base) {
+    this(base, base.getMessageBody());
+  }
+
+  public OutgoingEndSessionMessage(OutgoingTextMessage message, String body) {
+    super(message, body);
+  }
+
+  @Override
+  public boolean isEndSession() {
+    return true;
+  }
+
+  @Override
+  public OutgoingTextMessage withBody(String body) {
+    return new OutgoingEndSessionMessage(this, body);
+  }
+}

src/org/thoughtcrime/securesms/sms/OutgoingTextMessage.java

@@ -52,6 +52,10 @@ public class OutgoingTextMessage {
     return false;
   }
 
+  public boolean isEndSession() {
+    return false;
+  }
+
   public boolean isPreKeyBundle() {
     return false;
   }
@@ -61,6 +65,8 @@ public class OutgoingTextMessage {
       return new OutgoingEncryptedMessage(record.getIndividualRecipient(), record.getBody().getBody());
     } else if (record.isKeyExchange()) {
       return new OutgoingKeyExchangeMessage(record.getIndividualRecipient(), record.getBody().getBody());
+    } else if (record.isEndSession()) {
+      return new OutgoingEndSessionMessage(new OutgoingTextMessage(record.getIndividualRecipient(), record.getBody().getBody()));
     } else {
       return new OutgoingTextMessage(record.getIndividualRecipient(), record.getBody().getBody());
     }

src/org/thoughtcrime/securesms/transport/PushTransport.java

@@ -22,6 +22,7 @@ import android.util.Log;
 
 import com.google.protobuf.ByteString;
 
+import org.thoughtcrime.securesms.crypto.KeyExchangeProcessor;
 import org.thoughtcrime.securesms.crypto.KeyExchangeProcessorV2;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.database.model.SmsMessageRecord;
@@ -85,12 +86,15 @@ public class PushTransport extends BaseTransport {
       Recipient         recipient = message.getIndividualRecipient();
       long              threadId  = message.getThreadId();
       PushServiceSocket socket    = PushServiceSocketFactory.create(context);
-      byte[]            plaintext = PushMessageContent.newBuilder()
+      byte[]            plaintext = getPlaintextMessage(message);
-                                                      .setBody(message.getBody().getBody())
-                                                      .build().toByteArray();
 
       deliver(socket, recipient, threadId, plaintext);
 
+      if (message.isEndSession()) {
+        SessionRecordV2.deleteAll(context, recipient);
+        KeyExchangeProcessor.broadcastSecurityUpdateEvent(context, threadId);
+      }
+
       context.sendBroadcast(constructSentIntent(context, message.getId(), message.getType(), true));
 
     } catch (InvalidNumberException e) {
@@ -295,6 +299,17 @@ public class PushTransport extends BaseTransport {
     return builder.build().toByteArray();
   }
 
+  private byte[] getPlaintextMessage(SmsMessageRecord record) {
+    PushMessageContent.Builder builder = PushMessageContent.newBuilder()
+                                                           .setBody(record.getBody().getBody());
+
+    if (record.isEndSession()) {
+      builder.setFlags(PushMessageContent.Flags.END_SESSION_VALUE);
+    }
+
+    return builder.build().toByteArray();
+  }
+
   private OutgoingPushMessageList getEncryptedMessages(PushServiceSocket socket, long threadId,
                                                        Recipient recipient, byte[] plaintext)
       throws IOException, InvalidNumberException, UntrustedIdentityException
@@ -352,8 +367,4 @@ public class PushTransport extends BaseTransport {
       throw new AssertionError("Unknown ciphertext type: " + message.getType());
     }
   }
-
-  private void destroySessions(Recipient recipient) {
-    SessionRecordV2.deleteAll(context, recipient);
-  }
 }

src/org/thoughtcrime/securesms/transport/SmsTransport.java

@@ -33,6 +33,7 @@ import org.whispersystems.textsecure.crypto.MasterSecret;
 import org.whispersystems.textsecure.crypto.SessionCipher;
 import org.whispersystems.textsecure.crypto.protocol.CiphertextMessage;
 import org.whispersystems.textsecure.storage.RecipientDevice;
+import org.whispersystems.textsecure.util.Hex;
 
 import java.util.ArrayList;
 
@@ -47,7 +48,7 @@ public class SmsTransport extends BaseTransport {
   }
 
   public void deliver(SmsMessageRecord message) throws UndeliverableMessageException {
-    if (message.isSecure() || message.isKeyExchange()) {
+    if (message.isSecure() || message.isKeyExchange() || message.isEndSession()) {
       deliverSecureMessage(message);
     } else {
       deliverPlaintextMessage(message);
@@ -58,7 +59,7 @@ public class SmsTransport extends BaseTransport {
     MultipartSmsMessageHandler multipartMessageHandler = new MultipartSmsMessageHandler();
     OutgoingTextMessage transportMessage               = OutgoingTextMessage.from(message);
 
-    if (message.isSecure()) {
+    if (message.isSecure() || message.isEndSession()) {
       transportMessage = getAsymmetricEncrypt(masterSecret, transportMessage);
     }
 

src/org/thoughtcrime/securesms/util/Util.java

@@ -19,12 +19,12 @@ package org.thoughtcrime.securesms.util;
 import android.annotation.SuppressLint;
 import android.content.Context;
 import android.graphics.Typeface;
+import android.os.Build;
+import android.provider.Telephony;
 import android.text.Spannable;
 import android.text.SpannableString;
 import android.text.style.StyleSpan;
 import android.util.Log;
-import android.os.Build;
-import android.provider.Telephony;
 
 import org.whispersystems.textsecure.util.InvalidNumberException;
 import org.whispersystems.textsecure.util.PhoneNumberFormatter;