diff --git a/app/pgp_utils.py b/app/pgp_utils.py
index 403077a6..60e54cd3 100644
--- a/app/pgp_utils.py
+++ b/app/pgp_utils.py
@@ -1,5 +1,6 @@
 import os
 from io import BytesIO
+from typing import Union
 
 import gnupg
 import pgpy
@@ -101,12 +102,12 @@ if PGP_SENDER_PRIVATE_KEY:
     _SIGN_KEY_ID = gpg.import_keys(PGP_SENDER_PRIVATE_KEY).fingerprints[0]
 
 
-def sign_data(data: str) -> str:
+def sign_data(data: Union[str, bytes]) -> str:
     signature = str(gpg.sign(data, keyid=_SIGN_KEY_ID, detach=True))
     return signature
 
 
-def sign_data_with_pgpy(data: str) -> str:
+def sign_data_with_pgpy(data: Union[str, bytes]) -> str:
     key = pgpy.PGPKey()
     key.parse(PGP_SENDER_PRIVATE_KEY)
     signature = str(key.sign(data))
diff --git a/tests/test.env b/tests/test.env
index ccf0ed67..96afe6aa 100644
--- a/tests/test.env
+++ b/tests/test.env
@@ -57,3 +57,5 @@ GOOGLE_CLIENT_SECRET=to_fill
 # Facebook
 FACEBOOK_CLIENT_ID=to_fill
 FACEBOOK_CLIENT_SECRET=to_fill
+
+PGP_SENDER_PRIVATE_KEY_PATH=local_data/private-pgp.asc
\ No newline at end of file
diff --git a/tests/test_pgp_utils.py b/tests/test_pgp_utils.py
index f72c79f4..df4be522 100644
--- a/tests/test_pgp_utils.py
+++ b/tests/test_pgp_utils.py
@@ -10,6 +10,8 @@ from app.pgp_utils import (
     gpg,
     encrypt_file,
     encrypt_file_with_pgpy,
+    sign_data,
+    sign_data_with_pgpy,
 )
 
 
@@ -51,3 +53,13 @@ def encrypt_decrypt_text(text: str):
         assert decrypted == text
     elif type(decrypted) == bytearray:
         assert decrypted.decode() == text
+
+
+def test_sign_data():
+    assert sign_data("heyhey")
+    assert sign_data(b"bytes")
+
+
+def test_sign_data_with_pgpy():
+    assert sign_data_with_pgpy("unicode")
+    assert sign_data_with_pgpy(b"bytes")