PacketWriter is implemented by two classes: PacketWriterImpl and

PacketEncrypter. The separation allows authentication and encryption
to be tested separately.

api/net/sf/briar/api/crypto/CryptoComponent.java

@@ -4,6 +4,7 @@ import java.security.KeyPair;
 import java.security.MessageDigest;
 import java.security.Signature;
 
+import javax.crypto.Cipher;
 import javax.crypto.Mac;
 import javax.crypto.SecretKey;
 
@@ -19,5 +20,9 @@ public interface CryptoComponent {
 
 	MessageDigest getMessageDigest();
 
+	Cipher getPacketCipher();
+
 	Signature getSignature();
+
+	Cipher getTagCipher();
 }

api/net/sf/briar/api/transport/PacketWriter.java

@@ -4,8 +4,8 @@ import java.io.IOException;
 import java.io.OutputStream;
 
 /**
- * A filter that adds tags and MACs to outgoing packets. Encryption is handled
- * by the underlying output stream.
+ * A filter that adds tags and MACs to outgoing packets, encrypts them and
+ * writes them to the underlying output stream.
  */
 public interface PacketWriter {