fix 410, blank string as db password

Author: Evidlo

CHANGELOG.rst

@@ -1,3 +1,5 @@
+- fixed #410 - support empty string as password
+
 4.1.0 - 2024-06-26
 ------------------
 - merged #389 - add PyKeePass.database_name and database_description

pykeepass/kdbx_parsing/common.py

@@ -121,7 +121,7 @@ def compute_key_composite(password=None, keyfile=None):
     Used in header verification and payload decryption."""
 
     # hash the password
-    if password:
+    if password is not None:
         password_composite = hashlib.sha256(password.encode('utf-8')).digest()
     else:
         password_composite = b''

tests/tests.py

@@ -1170,6 +1170,7 @@ def test_open_save(self):
             base_dir / 'test4_chacha20_uncompressed.kdbx',# KDBX v4 ChaCha uncompressed
             base_dir / 'test4_argon2id.kdbx',        # KDBX v4 Argon2id
             base_dir / 'test4.kdbx',        # KDBX v4 with keyfile file descriptor
+            base_dir / 'test4_blankpass.kdbx',        # KDBX v4 blank password
         ]
         filenames_out = [
             base_dir / 'test3.kdbx.out',
@@ -1186,6 +1187,7 @@ def test_open_save(self):
             base_dir / 'test4_chacha20_uncompressed.kdbx.out',# KDBX v4 ChaCha uncompressed
             base_dir / 'test4_argon2id.kdbx.out',
             base_dir / 'test4.kdbx.out',        # KDBX v4 with keyfile file descriptor
+            base_dir / 'test4_blankpass.kdbx.out',        # KDBX v4 with keyfile file descriptor
         ]
         passwords = [
             'password',
@@ -1202,6 +1204,7 @@ def test_open_save(self):
             'password',
             'password',
             'password',
+            '',
         ]
         transformed_keys = [
             None,
@@ -1218,6 +1221,7 @@ def test_open_save(self):
             None,
             None,
             None,
+            None,
  ]
         keyfiles = [
             base_dir / 'test3.key',
@@ -1233,7 +1237,8 @@ def test_open_save(self):
             None,
             None,
             None,
-            keyfile_fd
+            keyfile_fd,
+            base_dir / 'test4.key',
         ]
         encryption_algorithms = [
             'aes256',
@@ -1250,6 +1255,7 @@ def test_open_save(self):
             'chacha20',
             'aes256',
             'chacha20',
+            'aes256',
         ]
         kdf_algorithms = [
             'aeskdf',
@@ -1266,6 +1272,7 @@ def test_open_save(self):
             'argon2',
             'argon2id',
             'argon2',
+            'argon2',
         ]
         versions = [
             (3, 1),
@@ -1282,6 +1289,7 @@ def test_open_save(self):
             (4, 0),
             (4, 0),
             (4, 0),
+            (4, 0),
         ]
 
         for (filename_in, filename_out, password, transformed_key,