diff --git a/boards/models/post/manager.py b/boards/models/post/manager.py
--- a/boards/models/post/manager.py
+++ b/boards/models/post/manager.py
@@ -75,7 +75,7 @@ class PostManager(models.Manager):
         return post
 
     @transaction.atomic
-    def import_post(self, title: str, text: str, pub_time: str,
+    def import_post(self, title: str, text: str, pub_time: str, global_id,
                     opening_post=None, tags=list()):
         if opening_post is None:
             thread = boards.models.thread.Thread.objects.create(
@@ -88,7 +88,7 @@ class PostManager(models.Manager):
                            pub_time=pub_time,
                            poster_ip=NO_IP,
                            last_edit_time=pub_time,
-                           thread_id=thread.id)
+                           thread_id=thread.id, global_id=global_id)
 
         post.build_url()
         post.connect_replies()
diff --git a/boards/models/post/sync.py b/boards/models/post/sync.py
--- a/boards/models/post/sync.py
+++ b/boards/models/post/sync.py
@@ -107,10 +107,7 @@ class SyncManager:
             for tag_model in tag_models:
                 tag_content = tag_model.find(TAG_CONTENT)
 
-                valid = SyncManager._verify_model(tag_content, tag_model)
-
-                if not valid:
-                    raise Exception('Invalid model signature')
+                signatures = SyncManager._verify_model(tag_content, tag_model)
 
                 tag_id = tag_content.find(TAG_ID)
                 global_id, exists = GlobalId.from_xml_element(tag_id)
@@ -119,6 +116,9 @@ class SyncManager:
                     print('Post with same ID already exists')
                 else:
                     global_id.save()
+                    for signature in signatures:
+                        signature.global_id = global_id
+                        signature.save()
 
                     title = tag_content.find(TAG_TITLE).text
                     text = tag_content.find(TAG_TEXT).text
@@ -143,8 +143,8 @@ class SyncManager:
 
                     post = Post.objects.import_post(
                         title=title, text=text, pub_time=pub_time,
-                        opening_post=opening_post, tags=tags)
-                    post.global_id = global_id
+                        opening_post=opening_post, tags=tags,
+                        global_id=global_id)
         else:
             # TODO Throw an exception?
             pass
@@ -155,7 +155,7 @@ class SyncManager:
         Verifies all signatures for a single model.
         """
 
-        valid = True
+        signatures = []
 
         tag_signatures = tag_model.find(TAG_SIGNATURES)
         for tag_signature in tag_signatures:
@@ -163,11 +163,13 @@ class SyncManager:
             signature_value = tag_signature.get(ATTR_VALUE)
             signature_key = tag_signature.get(ATTR_KEY)
 
+            signature = Signature(key_type=signature_type,
+                                  key=signature_key,
+                                  signature=signature_value)
+            signatures.append(signature)
+
             if not KeyPair.objects.verify(
-                    signature_key,
-                    et.tostring(tag_content, ENCODING_UNICODE),
-                    signature_value, signature_type):
-                valid = False
-                break
+                    signature, et.tostring(tag_content, ENCODING_UNICODE)):
+                raise Exception('Invalid model signature')
 
-        return valid
+        return signatures
diff --git a/boards/models/sync_key.py b/boards/models/sync_key.py
--- a/boards/models/sync_key.py
+++ b/boards/models/sync_key.py
@@ -25,10 +25,10 @@ class KeyPairManager(models.Manager):
         else:
             raise Exception('Key type not supported')
 
-    def verify(self, public_key_str, string, signature, key_type=TYPE_ECDSA):
-        if key_type == TYPE_ECDSA:
-            public = VerifyingKey.from_string(base64.b64decode(public_key_str))
-            signature_byte = base64.b64decode(signature)
+    def verify(self, signature, string):
+        if signature.key_type == TYPE_ECDSA:
+            public = VerifyingKey.from_string(base64.b64decode(signature.key))
+            signature_byte = base64.b64decode(signature.signature)
             try:
                 return public.verify(signature_byte, string.encode())
             except BadSignatureError:
diff --git a/boards/tests/test_keys.py b/boards/tests/test_keys.py
--- a/boards/tests/test_keys.py
+++ b/boards/tests/test_keys.py
@@ -2,7 +2,7 @@ from base64 import b64encode
 import logging
 
 from django.test import TestCase
-from boards.models import KeyPair, GlobalId, Post
+from boards.models import KeyPair, GlobalId, Post, Signature
 from boards.models.post.sync import SyncManager
 
 logger = logging.getLogger(__name__)
@@ -17,9 +17,11 @@ class KeyTest(TestCase):
     def test_validation(self):
         key = KeyPair.objects.generate_key(key_type='ecdsa')
         message = 'msg'
-        signature = key.sign(message)
-        valid = KeyPair.objects.verify(key.public_key, message, signature,
-                                       key_type='ecdsa')
+        signature_value = key.sign(message)
+
+        signature = Signature(key_type='ecdsa', key=key.public_key,
+                              signature=signature_value)
+        valid = KeyPair.objects.verify(signature, message)
 
         self.assertTrue(valid, 'Message verification failed.')
 
diff --git a/boards/tests/test_sync.py b/boards/tests/test_sync.py
--- a/boards/tests/test_sync.py
+++ b/boards/tests/test_sync.py
@@ -67,3 +67,6 @@ class SyncTest(TestCase):
         SyncManager.parse_response_get(response)
         self.assertEqual(1, Post.objects.count(),
                          'The same post was imported twice.')
+
+        self.assertEqual(1, parsed_post.global_id.signature_set.count(),
+                         'Signature was not saved.')