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Diffstat (limited to 'frozen_deps/Cryptodome/Hash/Poly1305.py')
| -rw-r--r-- | frozen_deps/Cryptodome/Hash/Poly1305.py | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/frozen_deps/Cryptodome/Hash/Poly1305.py b/frozen_deps/Cryptodome/Hash/Poly1305.py new file mode 100644 index 0000000..c03f522 --- /dev/null +++ b/frozen_deps/Cryptodome/Hash/Poly1305.py @@ -0,0 +1,217 @@ +# -*- coding: utf-8 -*- +# +# Hash/Poly1305.py - Implements the Poly1305 MAC +# +# =================================================================== +# The contents of this file are dedicated to the public domain. To +# the extent that dedication to the public domain is not available, +# everyone is granted a worldwide, perpetual, royalty-free, +# non-exclusive license to exercise all rights associated with the +# contents of this file for any purpose whatsoever. +# No rights are reserved. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS +# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN +# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +# SOFTWARE. +# =================================================================== + +from binascii import unhexlify + +from Cryptodome.Util.py3compat import bord, tobytes, _copy_bytes + +from Cryptodome.Hash import BLAKE2s +from Cryptodome.Random import get_random_bytes +from Cryptodome.Util._raw_api import (load_pycryptodome_raw_lib, + VoidPointer, SmartPointer, + create_string_buffer, + get_raw_buffer, c_size_t, + c_uint8_ptr) + + +_raw_poly1305 = load_pycryptodome_raw_lib("Cryptodome.Hash._poly1305", + """ + int poly1305_init(void **state, + const uint8_t *r, + size_t r_len, + const uint8_t *s, + size_t s_len); + int poly1305_destroy(void *state); + int poly1305_update(void *state, + const uint8_t *in, + size_t len); + int poly1305_digest(const void *state, + uint8_t *digest, + size_t len); + """) + + +class Poly1305_MAC(object): + """An Poly1305 MAC object. + Do not instantiate directly. Use the :func:`new` function. + + :ivar digest_size: the size in bytes of the resulting MAC tag + :vartype digest_size: integer + """ + + digest_size = 16 + + def __init__(self, r, s, data): + + if len(r) != 16: + raise ValueError("Parameter r is not 16 bytes long") + if len(s) != 16: + raise ValueError("Parameter s is not 16 bytes long") + + self._mac_tag = None + + state = VoidPointer() + result = _raw_poly1305.poly1305_init(state.address_of(), + c_uint8_ptr(r), + c_size_t(len(r)), + c_uint8_ptr(s), + c_size_t(len(s)) + ) + if result: + raise ValueError("Error %d while instantiating Poly1305" % result) + self._state = SmartPointer(state.get(), + _raw_poly1305.poly1305_destroy) + if data: + self.update(data) + + def update(self, data): + """Authenticate the next chunk of message. + + Args: + data (byte string/byte array/memoryview): The next chunk of data + """ + + if self._mac_tag: + raise TypeError("You can only call 'digest' or 'hexdigest' on this object") + + result = _raw_poly1305.poly1305_update(self._state.get(), + c_uint8_ptr(data), + c_size_t(len(data))) + if result: + raise ValueError("Error %d while hashing Poly1305 data" % result) + return self + + def copy(self): + raise NotImplementedError() + + def digest(self): + """Return the **binary** (non-printable) MAC tag of the message + authenticated so far. + + :return: The MAC tag digest, computed over the data processed so far. + Binary form. + :rtype: byte string + """ + + if self._mac_tag: + return self._mac_tag + + bfr = create_string_buffer(16) + result = _raw_poly1305.poly1305_digest(self._state.get(), + bfr, + c_size_t(len(bfr))) + if result: + raise ValueError("Error %d while creating Poly1305 digest" % result) + + self._mac_tag = get_raw_buffer(bfr) + return self._mac_tag + + def hexdigest(self): + """Return the **printable** MAC tag of the message authenticated so far. + + :return: The MAC tag, computed over the data processed so far. + Hexadecimal encoded. + :rtype: string + """ + + return "".join(["%02x" % bord(x) + for x in tuple(self.digest())]) + + def verify(self, mac_tag): + """Verify that a given **binary** MAC (computed by another party) + is valid. + + Args: + mac_tag (byte string/byte string/memoryview): the expected MAC of the message. + + Raises: + ValueError: if the MAC does not match. It means that the message + has been tampered with or that the MAC key is incorrect. + """ + + secret = get_random_bytes(16) + + mac1 = BLAKE2s.new(digest_bits=160, key=secret, data=mac_tag) + mac2 = BLAKE2s.new(digest_bits=160, key=secret, data=self.digest()) + + if mac1.digest() != mac2.digest(): + raise ValueError("MAC check failed") + + def hexverify(self, hex_mac_tag): + """Verify that a given **printable** MAC (computed by another party) + is valid. + + Args: + hex_mac_tag (string): the expected MAC of the message, + as a hexadecimal string. + + Raises: + ValueError: if the MAC does not match. It means that the message + has been tampered with or that the MAC key is incorrect. + """ + + self.verify(unhexlify(tobytes(hex_mac_tag))) + + + +def new(**kwargs): + """Create a new Poly1305 MAC object. + + Args: + key (bytes/bytearray/memoryview): + The 32-byte key for the Poly1305 object. + cipher (module from ``Cryptodome.Cipher``): + The cipher algorithm to use for deriving the Poly1305 + key pair *(r, s)*. + It can only be ``Cryptodome.Cipher.AES`` or ``Cryptodome.Cipher.ChaCha20``. + nonce (bytes/bytearray/memoryview): + Optional. The non-repeatable value to use for the MAC of this message. + It must be 16 bytes long for ``AES`` and 8 or 12 bytes for ``ChaCha20``. + If not passed, a random nonce is created; you will find it in the + ``nonce`` attribute of the new object. + data (bytes/bytearray/memoryview): + Optional. The very first chunk of the message to authenticate. + It is equivalent to an early call to ``update()``. + + Returns: + A :class:`Poly1305_MAC` object + """ + + cipher = kwargs.pop("cipher", None) + if not hasattr(cipher, '_derive_Poly1305_key_pair'): + raise ValueError("Parameter 'cipher' must be AES or ChaCha20") + + cipher_key = kwargs.pop("key", None) + if cipher_key is None: + raise TypeError("You must pass a parameter 'key'") + + nonce = kwargs.pop("nonce", None) + data = kwargs.pop("data", None) + + if kwargs: + raise TypeError("Unknown parameters: " + str(kwargs)) + + r, s, nonce = cipher._derive_Poly1305_key_pair(cipher_key, nonce) + + new_mac = Poly1305_MAC(r, s, data) + new_mac.nonce = _copy_bytes(None, None, nonce) # nonce may still be just a memoryview + return new_mac |