feat(api)!: expose _raw_ CBC wrappers, with manual padding

Leave room for a simpler `CBC_*crypt_buffer_inplace` with automatic padding

This is incompatible with the previous rc0, but the fix is a rename:

- CBC_encrypt_buffer_inplace -> CBC_encrypt_buffer_inplace_raw
- CBC_decrypt_buffer_inplace -> CBC_decrypt_buffer_inplace_raw

README.md

@@ -12,12 +12,13 @@ Given the C API works modifying a buffer in-place, the wrapper offers:
   encrypting a copy of the buffer,
 - `CTR_xcrypt_buffer_inplace(..)` that works on `bytearray`s only, modifying
   the buffer in-place.
-- `CBC_encrypt_buffer_inplace(..)` that works on `bytearray`s only, modifying
-  the buffer in-place.
-- `CBC_decrypt_buffer_inplace(..)` that works on `bytearray`s only, modifying
-  the buffer in-place.
+- `CBC_encrypt_buffer_inplace_raw(..)` that works on `bytearray`s only, modifying
+  the buffer in-place (manual padding).
+- `CBC_decrypt_buffer_inplace_raw(..)` that works on `bytearray`s only, modifying
+  the buffer in-place (manual unpadding).
+
+<details><summary>CBC usage Example:</summary>
 
-CBC usage Example:
 ```
 import tinyaes
 import binascii
@@ -42,14 +43,19 @@ print(text)  # b'hello'
 # padding plaintext to a multiple of block size
 text = pad(text)
 print(binascii.hexlify(bytearray(text)))  # b'68656c6c6f0b0b0b0b0b0b0b0b0b0b0b' hex representation of added text
-aes_enc.CBC_encrypt_buffer_inplace(text)  # b'5adc04828f9421c34210b05fe5c92bfd' hex representation of encrypted text
+aes_enc.CBC_encrypt_buffer_inplace_raw(text)  # b'5adc04828f9421c34210b05fe5c92bfd' hex representation of encrypted text
 print(binascii.hexlify(bytearray(text)))
-aes_dec.CBC_decrypt_buffer_inplace(text)
+aes_dec.CBC_decrypt_buffer_inplace_raw(text)
 print(unpad(text)) # b'hello' decrypted, original text
 ```
 
+</details>
+
 ## Release notes
 
+- 1.1.0rc1 (Oct 2, 2023)
+  - Add Python 3.12 final to the matrix
+  - Expose _raw_ functions for CBC mode, with manual padding and unpadding
 - 1.1.0rc0 (13 Feb 2023)
   - Drop support for Python 2.7 (CI tests and builds are disabled, code may still work)
   - Add support for CBC mode (unstable API, inplace only, manual padding)

tests/test_tinyaes.py

@@ -116,21 +116,21 @@ def test_different_keys_do_not_decode(data, aes_enc, aes_dec2, aes_dec3):
 def test_different_keys_do_not_decode_cbc(data, aes_enc_cbc, aes_dec2_cbc):
     data = pad(data)
     original_data = data[:len(data) // 2] + data[len(data) // 2:]  # Force a copy not allowing any sharing
-    aes_enc_cbc.CBC_encrypt_buffer_inplace(data)
-    aes_dec2_cbc.CBC_decrypt_buffer_inplace(data)
+    aes_enc_cbc.CBC_encrypt_buffer_inplace_raw(data)
+    aes_dec2_cbc.CBC_decrypt_buffer_inplace_raw(data)
     assert data != original_data
 
 
 @given(data=binary(min_size=2, max_size=100))
 def test_cbc_decode(data, aes_enc2_cbc, aes_dec_cbc):
     data = pad(data)
     original_data = data[:len(data) // 2] + data[len(data) // 2:]  # Force a copy not allowing any sharing
-    aes_enc2_cbc.CBC_encrypt_buffer_inplace(data)
-    aes_dec_cbc.CBC_decrypt_buffer_inplace(data)
+    aes_enc2_cbc.CBC_encrypt_buffer_inplace_raw(data)
+    aes_dec_cbc.CBC_decrypt_buffer_inplace_raw(data)
     assert data == original_data
 
 
 def test_bad_block_size_cbc(aes_enc_cbc, aes_dec2_cbc):
     data = bytes.fromhex('00112233445566778899AA')
     with pytest.raises(ValueError, match=r"Length of plaintext must be multiple of.*"):
-        aes_enc_cbc.CBC_encrypt_buffer_inplace(data)
+        aes_enc_cbc.CBC_encrypt_buffer_inplace_raw(data)

tinyaes.pyx

@@ -31,11 +31,11 @@ cdef class AES:
     def CTR_xcrypt_buffer_inplace(self, bytearray data):
         tinyaes.AES_CTR_xcrypt_buffer(&self._ctx, data, len(data))
 
-    def CBC_encrypt_buffer_inplace(self, data):
+    def CBC_encrypt_buffer_inplace_raw(self, data):
         if len(data) % AES_KEYLEN:
             raise ValueError(f"Length of plaintext must be multiple of {AES_KEYLEN} bytes")
         tinyaes.AES_CBC_encrypt_buffer(&self._ctx, data, len(data))
-    def CBC_decrypt_buffer_inplace(self, data):
+    def CBC_decrypt_buffer_inplace_raw(self, data):
         if len(data) % AES_KEYLEN:
             raise ValueError(f"Length of plaintext must be multiple of {AES_KEYLEN} bytes")
         tinyaes.AES_CBC_decrypt_buffer(&self._ctx, data, len(data))