Add timestamp to Ursula for serialization

Add timestamp to deserialized vars in verify_node
Add timestamp when deserializing from batch

nucypher/characters/lawful.py

@@ -558,7 +558,10 @@ class Ursula(Character, VerifiableNode, Miner):
         certificate = self.rest_server_certificate()
         cert_vbytes = VariableLengthBytestring(certificate.public_bytes(Encoding.PEM))
 
-        as_bytes = bytes().join((bytes(self._interface_signature),
+        timestamp = maya.now().epoch.to_bytes(4, 'big')
+
+        as_bytes = bytes().join((timestamp,
+                                 bytes(self._interface_signature),
                                  bytes(identity_evidence),
                                  bytes(self.public_keys(SigningPower)),
                                  bytes(self.public_keys(EncryptingPower)),
@@ -592,7 +595,8 @@ class Ursula(Character, VerifiableNode, Miner):
                    federated_only: bool = False,
                    ) -> 'Ursula':
 
-        (signature,
+        (timestamp,
+         signature,
          identity_evidence,
          verifying_key,
          encrypting_key,
@@ -623,7 +627,8 @@ class Ursula(Character, VerifiableNode, Miner):
         stranger_ursulas = []
 
         ursulas_attrs = cls._internal_splitter.repeat(ursulas_as_bytes)
-        for (signature,
+        for (timestamp,
+             signature,
              identity_evidence,
              verifying_key,
              encrypting_key,

nucypher/network/nodes.py

@@ -117,7 +117,7 @@ class VerifiableNode:
                                                        port=self.rest_information()[0].port)
         if not response.status_code == 200:
             raise RuntimeError("Or something.")  # TODO: Raise an error here?  Or return False?  Or something?
-        signature, identity_evidence, verifying_key, encrypting_key, public_address, certificate_vbytes, rest_info = self._internal_splitter(response.content)
+        timestamp, signature, identity_evidence, verifying_key, encrypting_key, public_address, certificate_vbytes, rest_info = self._internal_splitter(response.content)
 
         verifying_keys_match = verifying_key == self.public_keys(SigningPower)
         encrypting_keys_match = encrypting_key == self.public_keys(EncryptingPower)