diff --git a/slixmpp_omemo/__init__.py b/slixmpp_omemo/__init__.py
index 0c62e1d..100a72f 100644
--- a/slixmpp_omemo/__init__.py
+++ b/slixmpp_omemo/__init__.py
@@ -16,7 +16,6 @@ from typing import Any, Dict, List, Optional, Set, Tuple, Union
 import os
 import json
 import base64
-import codecs
 import asyncio
 from slixmpp.plugins.xep_0060.stanza import Items, EventItems
 from slixmpp.plugins.xep_0004 import Form
@@ -83,7 +82,7 @@ def _load_device_id(data_dir: str) -> int:
 
 def fp_from_ik(identity_key: bytes) -> str:
     """Convert identityKey to a string representation (fingerprint)"""
-    return codecs.getencoder("hex")(identity_key)[0].decode("US-ASCII").upper()
+    return ":".join("{:02X}".format(octet) for octet in identity_key)
 
 
 def _parse_bundle(backend: Backend, bundle: Bundle) -> ExtendedPublicBundle: