Add tb serialize doc, small fix in message.go after rebase

protocol/message.go

@@ -92,8 +92,9 @@ type Response struct {
 	DirectoryResponse `json:",omitempty"`
 }
 
-// A CONIKS server sends a DirectoryResponse message when it returns cryptographic proofs
-// about the key directory to a CONIKS client.
+// A DirectoryResponse is a message that includes cryptographic proofs
+// about the key directory that a CONIKS key server returns to a
+// CONIKS client.
 type DirectoryResponse interface{}
 
 // A DirectoryProof response includes an authentication path AP for a

protocol/tb.go

@@ -24,6 +24,8 @@ type TemporaryBinding struct {
 	Signature []byte
 }
 
+// Serialize encodes the tb to a byte array with the following format:
+// [strSig, tb.Index, tb.Value].
 func (tb *TemporaryBinding) Serialize(strSig []byte) []byte {
 	var tbBytes []byte
 	tbBytes = append(tbBytes, strSig...)