827 lines
25 KiB
Python
827 lines
25 KiB
Python
"""aegis256x4 Python submodule.
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Simplified API: single functions can return newly allocated buffers or write
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into user-provided buffers via optional `into=` (and `mac_into=` for detached).
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Error return codes from the C library raise ValueError.
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"""
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# All modules are generated from aegis256x4.py by tools/gen_modules.py!
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# DO NOT EDIT OTHER ALGORITHM FILES MANUALLY!
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import errno
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import secrets
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from ._loader import ffi
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from ._loader import lib as _lib
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from .util import Buffer, new_aligned_struct
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# Constants exposed as functions in C; mirror them as integers at module import time
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KEYBYTES = _lib.aegis256x4_keybytes()
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NPUBBYTES = _lib.aegis256x4_npubbytes()
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ABYTES_MIN = _lib.aegis256x4_abytes_min()
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ABYTES_MAX = _lib.aegis256x4_abytes_max()
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TAILBYTES_MAX = _lib.aegis256x4_tailbytes_max()
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ALIGNMENT = 64
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RATE = 64
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def random_key() -> bytes:
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"""Generate a random key using cryptographically secure random bytes."""
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return secrets.token_bytes(KEYBYTES)
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def random_nonce() -> bytes:
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"""Generate a random nonce using cryptographically secure random bytes."""
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return secrets.token_bytes(NPUBBYTES)
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def _ptr(buf):
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return ffi.NULL if buf is None else ffi.from_buffer(buf)
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def encrypt_detached(
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key: Buffer,
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nonce: Buffer,
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message: Buffer,
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ad: Buffer | None = None,
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*,
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maclen: int = ABYTES_MIN,
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ct_into: Buffer | None = None,
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mac_into: Buffer | None = None,
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) -> tuple[bytearray | memoryview, bytearray | memoryview]:
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f"""Encrypt message with associated data, returning ciphertext and MAC separately.
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Args:
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key: Key ({KEYBYTES=}).
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nonce: Nonce ({NPUBBYTES=}).
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message: The plaintext message to encrypt.
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ad: Associated data (optional).
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maclen: MAC length (16 or 32, default 16).
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ct_into: Buffer to write ciphertext into (default: bytearray created).
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mac_into: Buffer to write MAC into (default: bytearray created).
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Returns:
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Tuple of (ciphertext, mac)
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Raises:
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TypeError: If lengths are invalid.
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RuntimeError: If encryption fails.
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"""
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if maclen not in (16, 32):
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raise TypeError("maclen must be 16 or 32")
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if len(key) != KEYBYTES:
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raise TypeError(f"key length must be {KEYBYTES}")
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if len(nonce) != NPUBBYTES:
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raise TypeError(f"nonce length must be {NPUBBYTES}")
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if ct_into is None:
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c = bytearray(len(message))
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else:
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if len(ct_into) < len(message):
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raise TypeError("ct_into length must be at least len(message)")
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c = ct_into
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if mac_into is None:
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mac = bytearray(maclen)
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else:
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if len(mac_into) < maclen:
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raise TypeError("mac_into length must be at least maclen")
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mac = mac_into
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rc = _lib.aegis256x4_encrypt_detached(
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ffi.from_buffer(c),
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ffi.from_buffer(mac),
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maclen,
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_ptr(message),
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len(message),
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_ptr(ad),
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0 if ad is None else len(ad),
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_ptr(nonce),
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_ptr(key),
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)
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if rc != 0:
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err_num = ffi.errno
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err_name = errno.errorcode.get(err_num, f"errno_{err_num}")
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raise RuntimeError(f"encrypt detached failed: {err_name}")
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return (
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c if ct_into is None else memoryview(c)[: len(message)],
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mac if mac_into is None else memoryview(mac)[:maclen],
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) # type: ignore
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def decrypt_detached(
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key: Buffer,
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nonce: Buffer,
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ct: Buffer,
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mac: Buffer,
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ad: Buffer | None = None,
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*,
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into: Buffer | None = None,
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) -> bytearray | memoryview:
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f"""Decrypt ciphertext with detached MAC and associated data.
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Args:
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key: Key ({KEYBYTES=}).
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nonce: Nonce ({NPUBBYTES=}).
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ct: The ciphertext to decrypt.
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mac: The MAC to verify.
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ad: Associated data (optional).
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into: Buffer to write plaintext into (default: bytearray created).
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Returns:
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Plaintext as bytearray if into not provided, memoryview of into otherwise.
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Raises:
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TypeError: If lengths are invalid.
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ValueError: If authentication fails.
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"""
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if len(key) != KEYBYTES:
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raise TypeError(f"key length must be {KEYBYTES}")
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if len(nonce) != NPUBBYTES:
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raise TypeError(f"nonce length must be {NPUBBYTES}")
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maclen = len(mac)
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if maclen not in (16, 32):
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raise TypeError("mac length must be 16 or 32")
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if into is None:
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out = bytearray(len(ct))
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else:
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if len(into) < len(ct):
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raise TypeError("into length must be at least len(ciphertext)")
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out = into
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rc = _lib.aegis256x4_decrypt_detached(
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ffi.from_buffer(out),
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_ptr(ct),
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len(ct),
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_ptr(mac),
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maclen,
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_ptr(ad),
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0 if ad is None else len(ad),
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_ptr(nonce),
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_ptr(key),
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)
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if rc != 0:
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raise ValueError("authentication failed")
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return out if into is None else memoryview(out)[: len(ct)] # type: ignore
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def encrypt(
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key: Buffer,
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nonce: Buffer,
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message: Buffer,
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ad: Buffer | None = None,
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*,
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maclen: int = ABYTES_MIN,
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into: Buffer | None = None,
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) -> bytearray | memoryview:
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f"""Encrypt message with associated data, returning ciphertext with appended MAC.
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Args:
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key: Key ({KEYBYTES=}).
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nonce: Nonce ({NPUBBYTES=}).
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message: The plaintext message to encrypt.
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ad: Associated data (optional).
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maclen: MAC length (16 or 32, default 16).
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into: Buffer to write ciphertext+MAC into (default: bytearray created).
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Returns:
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Ciphertext with appended MAC as bytearray if into not provided, memoryview of into otherwise.
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Raises:
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TypeError: If lengths are invalid.
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RuntimeError: If encryption fails.
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"""
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if maclen not in (16, 32):
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raise TypeError("maclen must be 16 or 32")
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if len(key) != KEYBYTES:
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raise TypeError(f"key length must be {KEYBYTES}")
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if len(nonce) != NPUBBYTES:
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raise TypeError(f"nonce length must be {NPUBBYTES}")
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if into is None:
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out = bytearray(len(message) + maclen)
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else:
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if len(into) < len(message) + maclen:
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raise TypeError("into length must be at least len(message)+maclen")
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out = into
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rc = _lib.aegis256x4_encrypt(
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ffi.from_buffer(out),
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maclen,
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_ptr(message),
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len(message),
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_ptr(ad),
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0 if ad is None else len(ad),
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_ptr(nonce),
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_ptr(key),
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)
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if rc != 0:
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err_num = ffi.errno
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err_name = errno.errorcode.get(err_num, f"errno_{err_num}")
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raise RuntimeError(f"encrypt failed: {err_name}")
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return out if into is None else memoryview(out)[: len(message) + maclen] # type: ignore
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def decrypt(
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key: Buffer,
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nonce: Buffer,
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ct: Buffer,
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ad: Buffer | None = None,
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*,
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maclen: int = ABYTES_MIN,
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into: Buffer | None = None,
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) -> bytearray | memoryview:
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f"""Decrypt ciphertext with appended MAC and associated data.
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Args:
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key: Key ({KEYBYTES=}).
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nonce: Nonce ({NPUBBYTES=}).
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ct: The ciphertext with MAC to decrypt.
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ad: Associated data (optional).
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maclen: MAC length (16 or 32, default 16).
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into: Buffer to write plaintext into (default: bytearray created).
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Returns:
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Plaintext as bytearray if into not provided, memoryview of into otherwise.
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Raises:
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TypeError: If lengths are invalid.
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ValueError: If authentication fails.
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"""
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if maclen not in (16, 32):
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raise TypeError("maclen must be 16 or 32")
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if len(key) != KEYBYTES:
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raise TypeError(f"key length must be {KEYBYTES}")
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if len(nonce) != NPUBBYTES:
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raise TypeError(f"nonce length must be {NPUBBYTES}")
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if len(ct) < maclen:
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raise TypeError("ciphertext too short for tag")
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expected_out = len(ct) - maclen
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if into is None:
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out = bytearray(expected_out)
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else:
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if len(into) < expected_out:
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raise TypeError(
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"into length must be at least len(ciphertext_with_tag)-maclen"
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)
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out = into
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rc = _lib.aegis256x4_decrypt(
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ffi.from_buffer(out),
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_ptr(ct),
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len(ct),
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maclen,
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_ptr(ad),
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0 if ad is None else len(ad),
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_ptr(nonce),
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_ptr(key),
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)
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if rc != 0:
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raise ValueError("authentication failed")
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return out if into is None else memoryview(out)[:expected_out] # type: ignore
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def stream(
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key: Buffer,
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nonce: Buffer | None,
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length: int | None = None,
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*,
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into: Buffer | None = None,
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) -> bytearray | Buffer:
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f"""Generate a stream of pseudorandom bytes.
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Args:
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key: Key ({KEYBYTES=}).
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nonce: Nonce ({NPUBBYTES=}, uses zeroes for nonce if None).
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length: Number of bytes to generate (required if into is None).
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into: Buffer to write stream into (default: bytearray created).
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Returns:
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Pseudorandom bytes as bytearray, or into returned directly.
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Raises:
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TypeError: If lengths are invalid or neither length nor into provided.
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"""
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if len(key) != KEYBYTES:
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raise TypeError(f"key length must be {KEYBYTES}")
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if nonce is not None and len(nonce) != NPUBBYTES:
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raise TypeError(f"nonce length must be {NPUBBYTES}")
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if into is None:
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if length is None:
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raise TypeError("provide either into or length")
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out = bytearray(length)
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else:
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if length is not None and len(into) < length:
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raise TypeError("into length must be at least length")
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out = into
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_lib.aegis256x4_stream(
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ffi.from_buffer(out),
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len(out),
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_ptr(nonce),
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_ptr(key),
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)
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return out if into is None else memoryview(out)[: length or len(out)] # type: ignore
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def encrypt_unauthenticated(
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key: Buffer,
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nonce: Buffer,
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message: Buffer,
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*,
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into: Buffer | None = None,
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) -> bytearray | memoryview:
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f"""Encrypt message without authentication (for testing/debugging).
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Args:
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key: Key ({KEYBYTES=}).
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nonce: Nonce ({NPUBBYTES=}).
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message: The plaintext message to encrypt.
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into: Buffer to write ciphertext into (default: bytearray created).
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Returns:
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Ciphertext as bytearray if into not provided, memoryview of into otherwise.
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Raises:
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TypeError: If lengths are invalid.
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"""
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if len(key) != KEYBYTES:
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raise TypeError(f"key length must be {KEYBYTES}")
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if len(nonce) != NPUBBYTES:
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raise TypeError(f"nonce length must be {NPUBBYTES}")
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if into is None:
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out = bytearray(len(message))
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else:
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if len(into) < len(message):
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raise TypeError("into length must be at least len(message)")
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out = into
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_lib.aegis256x4_encrypt_unauthenticated(
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ffi.from_buffer(out),
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_ptr(message),
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len(message),
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_ptr(nonce),
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_ptr(key),
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)
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return out if into is None else memoryview(out)[: len(message)] # type: ignore
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def decrypt_unauthenticated(
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key: Buffer,
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nonce: Buffer,
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ct: Buffer,
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*,
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into: Buffer | None = None,
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) -> bytearray | memoryview:
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f"""Decrypt ciphertext without authentication (for testing/debugging).
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Args:
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key: Key ({KEYBYTES=}).
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nonce: Nonce ({NPUBBYTES=}).
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ct: The ciphertext to decrypt.
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into: Buffer to write plaintext into (default: bytearray created).
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Returns:
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Plaintext as bytearray if into not provided, memoryview of into otherwise.
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Raises:
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TypeError: If lengths are invalid.
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"""
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if len(key) != KEYBYTES:
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raise TypeError(f"key length must be {KEYBYTES}")
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if len(nonce) != NPUBBYTES:
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raise TypeError(f"nonce length must be {NPUBBYTES}")
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if into is None:
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out = bytearray(len(ct))
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else:
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if len(into) < len(ct):
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raise TypeError("into length must be at least len(ciphertext)")
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out = into
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_lib.aegis256x4_decrypt_unauthenticated(
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ffi.from_buffer(out),
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_ptr(ct),
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len(ct),
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_ptr(nonce),
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_ptr(key),
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)
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return out if into is None else memoryview(out)[: len(ct)] # type: ignore
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# This is missing from C API but convenient to have here
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def mac(
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key: Buffer,
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nonce: Buffer,
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data: Buffer,
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maclen: int = ABYTES_MIN,
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into: Buffer | None = None,
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) -> bytearray | memoryview:
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f"""Compute a MAC for the given data in one shot.
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Args:
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key: Key ({KEYBYTES=})
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nonce: Nonce ({NPUBBYTES=})
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data: Data to MAC
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maclen: MAC length (16 or 32, default 16)
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into: Buffer to write MAC into (default: bytearray created)
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Returns:
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MAC bytes as bytearray if into not provided, memoryview of into otherwise
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"""
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mac_state = Mac(key, nonce)
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mac_state.update(data)
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return mac_state.final(maclen, into)
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class Mac:
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"""AEGIS-256X4 MAC state wrapper.
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Usage:
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mac = Mac(key, nonce)
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mac.update(data)
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tag = mac.final() # defaults to 16-byte MAC
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# or verify:
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mac2 = Mac(key, nonce); mac2.update(data); mac2.verify(tag)
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"""
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__slots__ = ("_st", "_owner")
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def __init__(
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self,
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key: Buffer,
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nonce: Buffer,
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_other=None,
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) -> None:
|
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f"""Initialize a MAC state with a nonce and key.
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Args:
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key: Key ({KEYBYTES=}).
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nonce: Nonce ({NPUBBYTES=}).
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Raises:
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TypeError: If key or nonce lengths are invalid.
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"""
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st, owner = new_aligned_struct("aegis256x4_mac_state", ALIGNMENT)
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self._st = st
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self._owner = owner
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if _other is not None: # clone path
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_lib.aegis256x4_mac_state_clone(self._st, _other._st)
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return
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# Normal init path
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if len(key) != KEYBYTES:
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raise TypeError(f"key length must be {KEYBYTES}")
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if len(nonce) != NPUBBYTES:
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raise TypeError(f"nonce length must be {NPUBBYTES}")
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_lib.aegis256x4_mac_init(self._st, _ptr(key), _ptr(nonce))
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def __deepcopy__(self) -> "Mac":
|
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"""Return a clone of current MAC state."""
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return Mac(b"", b"", _other=self)
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clone = __deepcopy__
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def reset(self) -> None:
|
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"""Reset the MAC state so it can be reused with the same nonce and key."""
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_lib.aegis256x4_mac_reset(self._st)
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def update(self, data: Buffer) -> None:
|
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"""Absorb data into the MAC state.
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Args:
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data: Bytes-like object to authenticate.
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Raises:
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RuntimeError: If the underlying C function reports an error.
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"""
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rc = _lib.aegis256x4_mac_update(self._st, _ptr(data), len(data))
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if rc != 0:
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err_num = ffi.errno
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err_name = errno.errorcode.get(err_num, f"errno_{err_num}")
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raise RuntimeError(f"mac update failed: {err_name}")
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def final(
|
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self,
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maclen: int = ABYTES_MIN,
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into: Buffer | None = None,
|
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) -> bytearray | memoryview:
|
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"""Finalize and return the MAC tag.
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|
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Args:
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maclen: Tag length in bytes (16 or 32). Defaults to 16.
|
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into: Optional buffer to write the tag into (default: bytearray created).
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|
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Returns:
|
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The tag as bytearray if into not provided, memoryview of into otherwise.
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|
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Raises:
|
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TypeError: If lengths are invalid.
|
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RuntimeError: If finalization fails in the C library.
|
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"""
|
|
if maclen not in (16, 32):
|
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raise TypeError("maclen must be 16 or 32")
|
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if into is None:
|
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out = bytearray(maclen)
|
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else:
|
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if len(into) < maclen:
|
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raise TypeError("into length must be at least maclen")
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out = into
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out_mv = memoryview(out)
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rc = _lib.aegis256x4_mac_final(self._st, ffi.from_buffer(out_mv), maclen)
|
|
if rc != 0:
|
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err_num = ffi.errno
|
|
err_name = errno.errorcode.get(err_num, f"errno_{err_num}")
|
|
raise RuntimeError(f"mac final failed: {err_name}")
|
|
return out if into is None else memoryview(out)[:maclen] # type: ignore
|
|
|
|
def verify(self, mac: Buffer) -> bool:
|
|
"""Verify a tag for the current MAC state.
|
|
|
|
Args:
|
|
mac: The tag to verify (16 or 32 bytes).
|
|
|
|
Returns:
|
|
True if verification succeeds.
|
|
|
|
Raises:
|
|
TypeError: If tag length is invalid.
|
|
ValueError: If verification fails.
|
|
"""
|
|
maclen = len(mac)
|
|
if maclen not in (16, 32):
|
|
raise TypeError("mac length must be 16 or 32")
|
|
rc = _lib.aegis256x4_mac_verify(self._st, _ptr(mac), maclen)
|
|
if rc != 0:
|
|
raise ValueError("mac verification failed")
|
|
return True
|
|
|
|
|
|
class Encryptor:
|
|
"""Incremental encryptor.
|
|
|
|
- update(message[, into]) -> returns produced ciphertext bytes
|
|
- final([into], maclen=16) -> returns tail+tag bytes
|
|
- final_detached([ct_into], [mac_into], maclen=16) -> returns (tail_bytes, mac)
|
|
"""
|
|
|
|
__slots__ = ("_st", "_owner", "_bytes_in", "_bytes_out")
|
|
|
|
def __init__(self, key: Buffer, nonce: Buffer, ad: Buffer | None = None):
|
|
f"""Create an incremental encryptor.
|
|
|
|
Args:
|
|
key: Key ({KEYBYTES=}).
|
|
nonce: Nonce ({NPUBBYTES=}).
|
|
ad: Associated data to bind to the encryption (optional).
|
|
|
|
Raises:
|
|
TypeError: If key or nonce lengths are invalid.
|
|
"""
|
|
if len(key) != KEYBYTES:
|
|
raise TypeError(f"key length must be {KEYBYTES}")
|
|
if len(nonce) != NPUBBYTES:
|
|
raise TypeError(f"nonce length must be {NPUBBYTES}")
|
|
st, owner = new_aligned_struct("aegis256x4_state", ALIGNMENT)
|
|
_lib.aegis256x4_state_init(
|
|
st,
|
|
_ptr(ad) if ad is not None else ffi.NULL,
|
|
0 if ad is None else len(ad),
|
|
_ptr(nonce),
|
|
_ptr(key),
|
|
)
|
|
self._st = st
|
|
self._owner = owner
|
|
self._bytes_in = 0
|
|
self._bytes_out = 0
|
|
|
|
@property
|
|
def bytes_in(self) -> int:
|
|
"""Total plaintext bytes fed to update() so far."""
|
|
return self._bytes_in
|
|
|
|
@property
|
|
def bytes_out(self) -> int:
|
|
"""Total ciphertext bytes produced so far.
|
|
|
|
Includes update() and final() output.
|
|
"""
|
|
return self._bytes_out
|
|
|
|
def update(
|
|
self, message: Buffer, into: Buffer | None = None
|
|
) -> bytearray | memoryview:
|
|
"""Encrypt a chunk of the message.
|
|
|
|
Args:
|
|
message: Plaintext bytes to encrypt.
|
|
into: Optional destination buffer; must be >= len(message).
|
|
|
|
Returns:
|
|
The ciphertext for this chunk as bytearray if into not provided, memoryview of into otherwise.
|
|
|
|
Raises:
|
|
TypeError: If destination buffer is too small.
|
|
RuntimeError: If the C update call fails.
|
|
"""
|
|
expected_out = len(message)
|
|
out = into if into is not None else bytearray(expected_out)
|
|
out_mv = memoryview(out)
|
|
if len(out_mv) < expected_out:
|
|
raise TypeError(
|
|
"into length must be >= expected output size for this update"
|
|
)
|
|
written = ffi.new("size_t *")
|
|
rc = _lib.aegis256x4_state_encrypt_update(
|
|
self._st,
|
|
ffi.from_buffer(out_mv),
|
|
len(out_mv),
|
|
written,
|
|
_ptr(message),
|
|
len(message),
|
|
)
|
|
if rc != 0:
|
|
err_num = ffi.errno
|
|
err_name = errno.errorcode.get(err_num, f"errno_{err_num}")
|
|
raise RuntimeError(
|
|
f"state encrypt update failed: {err_name} written {written[0]}"
|
|
)
|
|
w = int(written[0])
|
|
assert w == expected_out
|
|
self._bytes_in += len(message)
|
|
self._bytes_out += w
|
|
return out if into is None else memoryview(out)[:w] # type: ignore
|
|
|
|
def final(
|
|
self, into: Buffer | None = None, maclen: int = ABYTES_MIN
|
|
) -> bytearray | memoryview:
|
|
"""Finalize encryption, writing any remaining bytes and the tag.
|
|
|
|
Args:
|
|
into: Optional destination buffer for the tail and tag.
|
|
maclen: Tag length (16 or 32). Defaults to 16.
|
|
|
|
Returns:
|
|
A memoryview of the produced bytes (tail + tag) if into provided, bytearray slice otherwise.
|
|
|
|
Raises:
|
|
TypeError: If maclen is invalid.
|
|
RuntimeError: If the C final call fails.
|
|
"""
|
|
if maclen not in (16, 32):
|
|
raise TypeError("maclen must be 16 or 32")
|
|
# Only the authentication tag is produced here; allocate exactly maclen
|
|
out = into if into is not None else bytearray(maclen)
|
|
written = ffi.new("size_t *")
|
|
rc = _lib.aegis256x4_state_encrypt_final(
|
|
self._st,
|
|
ffi.from_buffer(out),
|
|
len(out),
|
|
written,
|
|
maclen,
|
|
)
|
|
if rc != 0:
|
|
err_num = ffi.errno
|
|
err_name = errno.errorcode.get(err_num, f"errno_{err_num}")
|
|
raise RuntimeError(f"state encrypt final failed: {err_name}")
|
|
w = int(written[0])
|
|
if into is None:
|
|
# Only the tag bytes are returned when we allocate the buffer
|
|
assert w == maclen
|
|
self._bytes_out += w
|
|
return out if into is None else memoryview(out)[:w] # type: ignore
|
|
|
|
|
|
class Decryptor:
|
|
"""Incremental decryptor.
|
|
|
|
- update(ciphertext[, into]) -> returns plaintext bytes
|
|
- final(mac) -> verifies the MAC tag
|
|
"""
|
|
|
|
__slots__ = ("_st", "_owner", "_bytes_in", "_bytes_out")
|
|
|
|
def __init__(self, key: Buffer, nonce: Buffer, ad: Buffer | None = None):
|
|
f"""Create an incremental decryptor for detached tags.
|
|
|
|
Args:
|
|
key: Key ({KEYBYTES=}).
|
|
nonce: Nonce ({NPUBBYTES=}).
|
|
ad: Associated data used during encryption (optional).
|
|
|
|
Raises:
|
|
TypeError: If key or nonce lengths are invalid.
|
|
"""
|
|
if len(key) != KEYBYTES:
|
|
raise TypeError(f"key length must be {KEYBYTES}")
|
|
if len(nonce) != NPUBBYTES:
|
|
raise TypeError(f"nonce length must be {NPUBBYTES}")
|
|
st, owner = new_aligned_struct("aegis256x4_state", ALIGNMENT)
|
|
_lib.aegis256x4_state_init(
|
|
st,
|
|
_ptr(ad) if ad is not None else ffi.NULL,
|
|
0 if ad is None else len(ad),
|
|
_ptr(nonce),
|
|
_ptr(key),
|
|
)
|
|
self._st = st
|
|
self._owner = owner
|
|
self._bytes_in = 0
|
|
self._bytes_out = 0
|
|
|
|
@property
|
|
def bytes_in(self) -> int:
|
|
"""Total ciphertext bytes fed to update() so far."""
|
|
return self._bytes_in
|
|
|
|
@property
|
|
def bytes_out(self) -> int:
|
|
"""Total plaintext bytes produced so far."""
|
|
return self._bytes_out
|
|
|
|
def update(self, ct: Buffer, into: Buffer | None = None) -> bytearray | memoryview:
|
|
"""Process a chunk of ciphertext.
|
|
|
|
Args:
|
|
ct: Ciphertext bytes (without MAC).
|
|
into: Optional destination buffer; must be >= len(ciphertext).
|
|
|
|
Returns:
|
|
A memoryview of the decrypted bytes for this chunk if into provided, bytearray otherwise.
|
|
|
|
Raises:
|
|
TypeError: If destination buffer is too small.
|
|
RuntimeError: If the C update call fails.
|
|
"""
|
|
expected_out = len(ct)
|
|
out = into if into is not None else bytearray(expected_out)
|
|
out_mv = memoryview(out)
|
|
if len(out_mv) < expected_out:
|
|
raise TypeError("into length must be >= required capacity for this update")
|
|
written = ffi.new("size_t *")
|
|
rc = _lib.aegis256x4_state_decrypt_detached_update(
|
|
self._st,
|
|
ffi.from_buffer(out_mv),
|
|
len(out_mv),
|
|
written,
|
|
_ptr(ct),
|
|
len(ct),
|
|
)
|
|
if rc != 0:
|
|
err_num = ffi.errno
|
|
err_name = errno.errorcode.get(err_num, f"errno_{err_num}")
|
|
raise RuntimeError(f"state decrypt update failed: {err_name}")
|
|
w = int(written[0])
|
|
assert w == expected_out, f"got {w}, expected {expected_out}, len(ct)={len(ct)}"
|
|
self._bytes_in += len(ct)
|
|
self._bytes_out += w
|
|
return out if into is None else memoryview(out)[:w] # type: ignore
|
|
|
|
def final(self, mac: Buffer) -> None:
|
|
"""Finalize decryption by verifying the MAC tag.
|
|
|
|
Args:
|
|
mac: Tag to verify (16 or 32 bytes).
|
|
|
|
Raises:
|
|
TypeError: If tag length is invalid.
|
|
ValueError: If authentication fails.
|
|
"""
|
|
maclen = len(mac)
|
|
if maclen not in (16, 32):
|
|
raise TypeError("mac length must be 16 or 32")
|
|
rc = _lib.aegis256x4_state_decrypt_detached_final(
|
|
self._st, ffi.NULL, 0, ffi.NULL, _ptr(mac), maclen
|
|
)
|
|
if rc != 0:
|
|
raise ValueError("authentication failed")
|
|
|
|
|
|
def new_state():
|
|
"""Allocate and return a new aegis256x4_state* with proper alignment."""
|
|
return new_aligned_struct("aegis256x4_state", ALIGNMENT)
|
|
|
|
|
|
def new_mac_state():
|
|
"""Allocate and return a new aegis256x4_mac_state* with proper alignment."""
|
|
return new_aligned_struct("aegis256x4_mac_state", ALIGNMENT)
|
|
|
|
|
|
__all__ = [
|
|
# constants
|
|
"KEYBYTES",
|
|
"NPUBBYTES",
|
|
"ABYTES_MIN",
|
|
"ABYTES_MAX",
|
|
"TAILBYTES_MAX",
|
|
"ALIGNMENT",
|
|
"RATE",
|
|
# one-shot functions
|
|
"encrypt_detached",
|
|
"decrypt_detached",
|
|
"encrypt",
|
|
"decrypt",
|
|
"stream",
|
|
"encrypt_unauthenticated",
|
|
"decrypt_unauthenticated",
|
|
"mac",
|
|
# incremental classes
|
|
"Encryptor",
|
|
"Decryptor",
|
|
"Mac",
|
|
]
|