[omemo] Add encrypt_file method

The HTTPUploadPlugin calls that if encryption is enabled

omemo/omemo/state.py

@@ -19,6 +19,7 @@
 
 import logging
 import time
+import os
 from base64 import b64encode
 
 from axolotl.ecc.djbec import DjbECPublicKey
@@ -216,6 +217,14 @@ class OmemoState:
         log.debug("Decrypted Message => " + result)
         return result
 
+    def encrypt_file(self, data):
+        key = os.urandom(32)
+        iv = os.urandom(16)
+
+        payload, tag = encrypt(key, iv, data)
+        encrypted_data = payload + tag
+        return (encrypted_data, key, iv)
+
     def create_msg(self, from_jid, jid, plaintext):
         key = get_random_bytes(16)
         iv = get_random_bytes(16)

omemo/omemoplugin.py

@@ -25,7 +25,10 @@ import os
 import sqlite3
 import shutil
 import nbxmpp
+import binascii
+import threading
 
+from gi.repository import GLib
 from nbxmpp.simplexml import Node
 from nbxmpp import NS_ADDRESS
 
@@ -201,6 +204,23 @@ class OmemoPlugin(GajimPlugin):
     def file_decryption(self, url, kind, instance, window):
         FileDecryption(self).hyperlink_handler(url, kind, instance, window)
 
+    def encrypt_file(self, file, account, callback):
+        thread = threading.Thread(target=self._encrypt_file_thread,
+                                  args=(file, account, callback))
+        thread.daemon = True
+        thread.start()
+
+    def _encrypt_file_thread(self, file, account, callback):
+        state = self.get_omemo_state(account)
+        encrypted_data, key, iv = state.encrypt_file(file.get_data(full=True))
+        file.encrypted = True
+        file.size = len(encrypted_data)
+        file.user_data = binascii.hexlify(iv + key).decode('utf-8')
+        file.data = encrypted_data
+        if file.event.isSet():
+            return
+        GLib.idle_add(callback, file)
+
     def signed_in(self, event):
         """ Method called on SignIn