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Constants renamed and values extracted from C code rather than function call at runtime. Documentation update.

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LeoVasanko
2025-11-09 03:43:01 +00:00
parent 28ee0e1314
commit 56d304a82e
9 changed files with 426 additions and 346 deletions
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pyaegis/aegis256x2.py
+52 -51
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@@ -9,24 +9,26 @@ from ._loader import ffi
from ._loader import lib as _lib
from .util import Buffer, new_aligned_struct, nonce_increment, wipe
# Constants exposed as functions in C; mirror them as integers at module import time
KEYBYTES = _lib.aegis256x2_keybytes()
NPUBBYTES = _lib.aegis256x2_npubbytes()
ABYTES_MIN = _lib.aegis256x2_abytes_min()
ABYTES_MAX = _lib.aegis256x2_abytes_max()
TAILBYTES_MAX = _lib.aegis256x2_tailbytes_max()
ALIGNMENT = 32
RATE = 32
KEYBYTES = 32 #: Key size in bytes (varies by algorithm)
NONCEBYTES = 32 #: Nonce size in bytes (varies by algorithm)
MACBYTES = 16 #: Normal MAC size (always 16)
MACBYTES_LONG = 32 #: Long MAC size (always 32)
ALIGNMENT = 64 #: Required alignment for internal structures
RATE = 64 #: Byte chunk size in internal processing
def random_key() -> bytearray:
"""Generate a random key using cryptographically secure random bytes."""
"""
Generate a random key using cryptographically secure random bytes.
It is recommended to wipe() the key after no longer needed to keep it secret.
"""
return bytearray(secrets.token_bytes(KEYBYTES))
def random_nonce() -> bytearray:
"""Generate a random nonce using cryptographically secure random bytes."""
return bytearray(secrets.token_bytes(NPUBBYTES))
return bytearray(secrets.token_bytes(NONCEBYTES))
def _ptr(buf):
@@ -39,7 +41,7 @@ def encrypt_detached(
message: Buffer,
ad: Buffer | None = None,
*,
maclen: int = ABYTES_MIN,
maclen: int = MACBYTES,
ct_into: Buffer | None = None,
mac_into: Buffer | None = None,
) -> tuple[bytearray | memoryview, bytearray | memoryview]:
@@ -47,7 +49,7 @@ def encrypt_detached(
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
message: The plaintext message to encrypt.
ad: Associated data (optional).
maclen: MAC length (16 or 32, default 16).
@@ -65,8 +67,8 @@ def encrypt_detached(
raise TypeError("maclen must be 16 or 32")
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
if ct_into is None:
c = bytearray(len(message))
@@ -115,7 +117,7 @@ def decrypt_detached(
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
ct: The ciphertext to decrypt.
mac: The MAC to verify.
ad: Associated data (optional).
@@ -130,8 +132,8 @@ def decrypt_detached(
"""
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
maclen = len(mac)
if maclen not in (16, 32):
raise TypeError("mac length must be 16 or 32")
@@ -164,14 +166,14 @@ def encrypt(
message: Buffer,
ad: Buffer | None = None,
*,
maclen: int = ABYTES_MIN,
maclen: int = MACBYTES,
into: Buffer | None = None,
) -> bytearray | memoryview:
f"""Encrypt message with associated data, returning ciphertext with appended MAC.
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
message: The plaintext message to encrypt.
ad: Associated data (optional).
maclen: MAC length (16 or 32, default 16).
@@ -188,8 +190,8 @@ def encrypt(
raise TypeError("maclen must be 16 or 32")
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
if into is None:
out = bytearray(len(message) + maclen)
else:
@@ -220,14 +222,14 @@ def decrypt(
ct: Buffer,
ad: Buffer | None = None,
*,
maclen: int = ABYTES_MIN,
maclen: int = MACBYTES,
into: Buffer | None = None,
) -> bytearray | memoryview:
f"""Decrypt ciphertext with appended MAC and associated data.
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
ct: The ciphertext with MAC to decrypt.
ad: Associated data (optional).
maclen: MAC length (16 or 32, default 16).
@@ -244,8 +246,8 @@ def decrypt(
raise TypeError("maclen must be 16 or 32")
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
if len(ct) < maclen:
raise TypeError("ciphertext too short for tag")
expected_out = len(ct) - maclen
@@ -284,7 +286,7 @@ def stream(
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}, uses zeroes for nonce if None).
nonce: Nonce ({NONCEBYTES=}, uses zeroes for nonce if None).
length: Number of bytes to generate (required if into is None).
into: Buffer to write stream into (default: bytearray created).
@@ -296,8 +298,8 @@ def stream(
"""
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if nonce is not None and len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if nonce is not None and len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
if into is None:
if length is None:
raise TypeError("provide either into or length")
@@ -326,7 +328,7 @@ def encrypt_unauthenticated(
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
message: The plaintext message to encrypt.
into: Buffer to write ciphertext into (default: bytearray created).
@@ -338,8 +340,8 @@ def encrypt_unauthenticated(
"""
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
if into is None:
out = bytearray(len(message))
else:
@@ -367,7 +369,7 @@ def decrypt_unauthenticated(
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
ct: The ciphertext to decrypt.
into: Buffer to write plaintext into (default: bytearray created).
@@ -379,8 +381,8 @@ def decrypt_unauthenticated(
"""
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
if into is None:
out = bytearray(len(ct))
else:
@@ -402,14 +404,14 @@ def mac(
key: Buffer,
nonce: Buffer,
data: Buffer,
maclen: int = ABYTES_MIN,
maclen: int = MACBYTES,
into: Buffer | None = None,
) -> bytearray | memoryview:
f"""Compute a MAC for the given data in one shot.
Args:
key: Key ({KEYBYTES=})
nonce: Nonce ({NPUBBYTES=})
nonce: Nonce ({NONCEBYTES=})
data: Data to MAC
maclen: MAC length (16 or 32, default 16)
into: Buffer to write MAC into (default: bytearray created)
@@ -445,7 +447,7 @@ class Mac:
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
Raises:
TypeError: If key or nonce lengths are invalid.
@@ -459,8 +461,8 @@ class Mac:
# Normal init path
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
_lib.aegis256x2_mac_init(self._st, _ptr(key), _ptr(nonce))
def __deepcopy__(self) -> "Mac":
@@ -490,7 +492,7 @@ class Mac:
def final(
self,
maclen: int = ABYTES_MIN,
maclen: int = MACBYTES,
into: Buffer | None = None,
) -> bytearray | memoryview:
"""Finalize and return the MAC tag.
@@ -558,7 +560,7 @@ class Encryptor:
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
ad: Associated data to bind to the encryption (optional).
Raises:
@@ -566,8 +568,8 @@ class Encryptor:
"""
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
st, owner = new_aligned_struct("aegis256x2_state", ALIGNMENT)
_lib.aegis256x2_state_init(
st,
@@ -639,7 +641,7 @@ class Encryptor:
return out if into is None else memoryview(out)[:w] # type: ignore
def final(
self, into: Buffer | None = None, maclen: int = ABYTES_MIN
self, into: Buffer | None = None, maclen: int = MACBYTES
) -> bytearray | memoryview:
"""Finalize encryption, writing any remaining bytes and the tag.
@@ -692,7 +694,7 @@ class Decryptor:
Args:
key: Key ({KEYBYTES=}).
nonce: Nonce ({NPUBBYTES=}).
nonce: Nonce ({NONCEBYTES=}).
ad: Associated data used during encryption (optional).
Raises:
@@ -700,8 +702,8 @@ class Decryptor:
"""
if len(key) != KEYBYTES:
raise TypeError(f"key length must be {KEYBYTES}")
if len(nonce) != NPUBBYTES:
raise TypeError(f"nonce length must be {NPUBBYTES}")
if len(nonce) != NONCEBYTES:
raise TypeError(f"nonce length must be {NONCEBYTES}")
st, owner = new_aligned_struct("aegis256x2_state", ALIGNMENT)
_lib.aegis256x2_state_init(
st,
@@ -796,10 +798,9 @@ def new_mac_state():
__all__ = [
# constants
"KEYBYTES",
"NPUBBYTES",
"ABYTES_MIN",
"ABYTES_MAX",
"TAILBYTES_MAX",
"NONCEBYTES",
"MACBYTES",
"MACBYTES_LONG",
"ALIGNMENT",
"RATE",
# utility functions