build: replace cryptography with pycryptodome for AES-GCM

core/crypto.py

@@ -5,8 +5,7 @@
 import struct
 from pathlib import Path
 
-from cryptography.exceptions import InvalidTag
-from cryptography.hazmat.primitives.ciphers.aead import AESGCM
+from Crypto.Cipher import AES
 
 from core.errors import PortabaseError
 
@@ -81,7 +80,6 @@ def _read_header(handle) -> tuple[bytes, int]:
 
 
 def decrypt_enc_file(enc_path: Path, out_path: Path, key: bytes) -> None:
-    aesgcm = AESGCM(key)
     tmp_path = out_path.with_name(out_path.name + ".part")
 
     try:
@@ -119,9 +117,12 @@ def decrypt_enc_file(enc_path: Path, out_path: Path, key: bytes) -> None:
                         )
 
                     nonce = base_nonce + struct.pack(">I", chunk_index)
+                    cipher = AES.new(key, AES.MODE_GCM, nonce=nonce)
                     try:
-                        plaintext = aesgcm.decrypt(nonce, ciphertext, None)
-                    except InvalidTag as exc:
+                        plaintext = cipher.decrypt_and_verify(
+                            ciphertext[:-_TAG_LEN], ciphertext[-_TAG_LEN:]
+                        )
+                    except ValueError as exc:
                         raise DecryptionError(
                             f"Authentication failed on chunk {chunk_index} "
                             "(wrong key or corrupt data)."

pyproject.toml

@@ -10,8 +10,7 @@ dependencies = [
     "questionary>=2.1.0",
     "requests>=2.32.5",
     "pyyaml>=6.0.3",
-    "cryptography>=44.0.0; sys_platform != 'darwin' or platform_machine != 'x86_64'",
-    "cryptography>=44.0.0,<49; sys_platform == 'darwin' and platform_machine == 'x86_64'",
+    "pycryptodome>=3.23.0",
     "jinja2>=3.1",
 ]
 

tests/support.py

@@ -8,7 +8,7 @@
 from pathlib import Path
 from typing import Any
 
-from cryptography.hazmat.primitives.ciphers.aead import AESGCM
+from Crypto.Cipher import AES
 
 from core.errors import NetworkError
 from core.fields import Field
@@ -113,11 +113,11 @@ def encrypt(plain: bytes, key: bytes, chunk_size: int = 4) -> bytes:
         "chunk_size": chunk_size,
     }
     out = json.dumps(header).encode() + b"\n"
-    aes = AESGCM(key)
     for index, start in enumerate(range(0, len(plain), chunk_size)):
         nonce = base_nonce + struct.pack(">I", index)
-        ciphertext = aes.encrypt(nonce, plain[start : start + chunk_size], None)
-        out += struct.pack(">I", len(ciphertext)) + ciphertext
+        cipher = AES.new(key, AES.MODE_GCM, nonce=nonce)
+        ciphertext, tag = cipher.encrypt_and_digest(plain[start : start + chunk_size])
+        out += struct.pack(">I", len(ciphertext) + len(tag)) + ciphertext + tag
     return out