def _create_base_cipher(dict_parameters):
"""This method instantiates and returns a handle to a low-level
base cipher. It will absorb named parameters in the process."""
try:
key = dict_parameters.pop("key")
except KeyError:
raise TypeError("Missing 'key' parameter")
effective_keylen = dict_parameters.pop("effective_keylen", 1024)
if len(key) not in key_size:
raise ValueError("Incorrect ARC2 key length (%d bytes)" % len(key))
if not (40 < effective_keylen <= 1024):
raise ValueError("'effective_key_len' must be no larger than 1024 "
"(not %d)" % effective_keylen)
start_operation = _raw_arc2_lib.ARC2_start_operation
stop_operation = _raw_arc2_lib.ARC2_stop_operation
cipher = VoidPointer()
result = start_operation(c_uint8_ptr(key), c_size_t(len(key)),
c_size_t(effective_keylen), cipher.address_of())
if result:
raise ValueError("Error %X while instantiating the ARC2 cipher" %
result)
return SmartPointer(cipher.get(), stop_operation)
def __init__(self, key, nonce):
"""Initialize a Salsa20 cipher object
See also `new()` at the module level."""
if len(key) not in key_size:
raise ValueError("Incorrect key length for Salsa20 (%d bytes)" % len(key))
if len(nonce) != 8:
raise ValueError("Incorrect nonce length for Salsa20 (%d bytes)" %
len(nonce))
self.nonce = _copy_bytes(None, None, nonce)
self._state = VoidPointer()
result = _raw_salsa20_lib.Salsa20_stream_init(
c_uint8_ptr(key),
c_size_t(len(key)),
c_uint8_ptr(nonce),
c_size_t(len(nonce)),
self._state.address_of())
if result:
raise ValueError("Error %d instantiating a Salsa20 cipher")
self._state = SmartPointer(self._state.get(),
_raw_salsa20_lib.Salsa20_stream_destroy)
self.block_size = 1
self.key_size = len(key)
def __init__(self, block_cipher, initial_counter_block, prefix_len,
counter_len, little_endian):
"""Create a new block cipher, configured in CTR mode.
:Parameters:
block_cipher : C pointer
A smart pointer to the low-level block cipher instance.
initial_counter_block : bytes/bytearray/memoryview
The initial plaintext to use to generate the key stream.
It is as large as the cipher block, and it embeds
the initial value of the counter.
This value must not be reused.
It shall contain a nonce or a random component.
Reusing the *initial counter block* for encryptions
performed with the same key compromises confidentiality.
prefix_len : integer
The amount of bytes at the beginning of the counter block
that never change.
counter_len : integer
The length in bytes of the counter embedded in the counter
block.
little_endian : boolean
True if the counter in the counter block is an integer encoded
in little endian mode. If False, it is big endian.
"""
if len(initial_counter_block) == prefix_len + counter_len:
self.nonce = _copy_bytes(None, prefix_len, initial_counter_block)
"""Nonce; not available if there is a fixed suffix"""
self._state = VoidPointer()
result = raw_ctr_lib.CTR_start_operation(
block_cipher.get(), c_uint8_ptr(initial_counter_block),
c_size_t(len(initial_counter_block)), c_size_t(prefix_len),
counter_len, little_endian, self._state.address_of())
if result:
raise ValueError("Error %X while instatiating the CTR mode" %
result)
# Ensure that object disposal of this Python object will (eventually)
# free the memory allocated by the raw library for the cipher mode
self._state = SmartPointer(self._state.get(),
raw_ctr_lib.CTR_stop_operation)
# Memory allocated for the underlying block cipher is now owed
# by the cipher mode
block_cipher.release()
self.block_size = len(initial_counter_block)
"""The block size of the underlying cipher, in bytes."""
self._next = [self.encrypt, self.decrypt]
def __init__(self, block_cipher, iv, segment_size):
"""Create a new block cipher, configured in CFB mode.
:Parameters:
block_cipher : C pointer
A smart pointer to the low-level block cipher instance.
iv : bytes/bytearray/memoryview
The initialization vector to use for encryption or decryption.
It is as long as the cipher block.
**The IV must be unpredictable**. Ideally it is picked randomly.
Reusing the *IV* for encryptions performed with the same key
compromises confidentiality.
segment_size : integer
The number of bytes the plaintext and ciphertext are segmented in.
"""
self._state = VoidPointer()
result = raw_cfb_lib.CFB_start_operation(block_cipher.get(),
c_uint8_ptr(iv),
c_size_t(len(iv)),
c_size_t(segment_size),
self._state.address_of())
if result:
raise ValueError("Error %d while instatiating the CFB mode" %
result)
# Ensure that object disposal of this Python object will (eventually)
# free the memory allocated by the raw library for the cipher mode
self._state = SmartPointer(self._state.get(),
raw_cfb_lib.CFB_stop_operation)
# Memory allocated for the underlying block cipher is now owed
# by the cipher mode
block_cipher.release()
self.block_size = len(iv)
"""The block size of the underlying cipher, in bytes."""
self.iv = _copy_bytes(None, None, iv)
"""The Initialization Vector originally used to create the object.
The value does not change."""
self.IV = self.iv
"""Alias for `iv`"""
self._next = [self.encrypt, self.decrypt]
def _pbkdf2_hmac_assist(inner, outer, first_digest, iterations):
"""Compute the expensive inner loop in PBKDF-HMAC."""
assert iterations > 0
bfr = create_string_buffer(len(first_digest))
result = _raw_sha256_lib.SHA256_pbkdf2_hmac_assist(
inner._state.get(), outer._state.get(), first_digest, bfr,
c_size_t(iterations), c_size_t(len(first_digest)))
if result:
raise ValueError("Error %d with PBKDF2-HMAC assist for SHA256" %
result)
return get_raw_buffer(bfr)
def decrypt(self, ciphertext, output=None):
"""Decrypt data with the key and the parameters set at initialization.
A cipher object is stateful: once you have decrypted a message
you cannot decrypt (or encrypt) another message with the same
object.
The data to decrypt can be broken up in two or
more pieces and `decrypt` can be called multiple times.
That is, the statement:
>>> c.decrypt(a) + c.decrypt(b)
is equivalent to:
>>> c.decrypt(a+b)
This function does not remove any padding from the plaintext.
:Parameters:
ciphertext : bytes/bytearray/memoryview
The piece of data to decrypt.
It can be of any length.
:Keywords:
output : bytearray/memoryview
The location where the plaintext must be written to.
If ``None``, the plaintext is returned.
:Return:
If ``output`` is ``None``, the plaintext is returned as ``bytes``.
Otherwise, ``None``.
"""
if self.decrypt not in self._next:
raise TypeError("decrypt() cannot be called after encrypt()")
self._next = [ self.decrypt ]
if output is None:
plaintext = create_string_buffer(len(ciphertext))
else:
plaintext = output
if not is_writeable_buffer(output):
raise TypeError("output must be a bytearray or a writeable memoryview")
if len(ciphertext) != len(output):
raise ValueError("output must have the same length as the input"
" (%d bytes)" % len(plaintext))
result = raw_cfb_lib.CFB_decrypt(self._state.get(),
c_uint8_ptr(ciphertext),
c_uint8_ptr(plaintext),
c_size_t(len(ciphertext)))
if result:
raise ValueError("Error %d while decrypting in CFB mode" % result)
if output is None:
return get_raw_buffer(plaintext)
else:
return None
def _create_base_cipher(dict_parameters):
"""This method instantiates and returns a handle to a low-level
base cipher. It will absorb named parameters in the process."""
use_aesni = dict_parameters.pop("use_aesni", True)
try:
key = dict_parameters.pop("key")
except KeyError:
raise TypeError("Missing 'key' parameter")
if len(key) not in key_size:
raise ValueError("Incorrect AES key length (%d bytes)" % len(key))
if use_aesni and _raw_aesni_lib:
start_operation = _raw_aesni_lib.AESNI_start_operation
stop_operation = _raw_aesni_lib.AESNI_stop_operation
else:
start_operation = _raw_aes_lib.AES_start_operation
stop_operation = _raw_aes_lib.AES_stop_operation
cipher = VoidPointer()
result = start_operation(c_uint8_ptr(key), c_size_t(len(key)),
cipher.address_of())
if result:
raise ValueError("Error %X while instantiating the AES cipher" %
result)
return SmartPointer(cipher.get(), stop_operation)
def _update(self, assoc_data, assoc_data_len):
result = _raw_ocb_lib.OCB_update(self._state.get(),
c_uint8_ptr(assoc_data),
c_size_t(assoc_data_len))
if result:
raise ValueError("Error %d while computing MAC in OCB mode" %
result)
def encrypt(self, plaintext):
"""Encrypt data with the key set at initialization.
The data to encrypt can be broken up in two or
more pieces and `encrypt` can be called multiple times.
That is, the statement:
>>> c.encrypt(a) + c.encrypt(b)
is equivalent to:
>>> c.encrypt(a+b)
This function does not add any padding to the plaintext.
:Parameters:
plaintext : bytes/bytearray/memoryview
The piece of data to encrypt.
The length must be multiple of the cipher block length.
:Return:
the encrypted data, as a byte string.
It is as long as *plaintext*.
"""
ciphertext = create_string_buffer(len(plaintext))
result = raw_ecb_lib.ECB_encrypt(self._state.get(),
c_uint8_ptr(plaintext), ciphertext,
c_size_t(len(plaintext)))
if result:
if result == 3:
raise ValueError(
"Data must be aligned to block boundary in ECB mode")
raise ValueError("Error %d while encrypting in ECB mode" % result)
return get_raw_buffer(ciphertext)
def __init__(self, x, y, curve="p256"):
try:
self._curve = _curves[curve]
except KeyError:
raise ValueError("Unknown curve name %s" % str(curve))
self._curve_name = curve
modulus_bytes = self.size_in_bytes()
context = self._curve.context
xb = long_to_bytes(x, modulus_bytes)
yb = long_to_bytes(y, modulus_bytes)
if len(xb) != modulus_bytes or len(yb) != modulus_bytes:
raise ValueError("Incorrect coordinate length")
self._point = VoidPointer()
result = _ec_lib.ec_ws_new_point(self._point.address_of(),
c_uint8_ptr(xb), c_uint8_ptr(yb),
c_size_t(modulus_bytes),
context.get())
if result:
if result == 15:
raise ValueError("The EC point does not belong to the curve")
raise ValueError("Error %d while instantiating an EC point" %
result)
# Ensure that object disposal of this Python object will (eventually)
# free the memory allocated by the raw library for the EC point
self._point = SmartPointer(self._point.get(), _ec_lib.ec_free_point)
def __init__(self, key, *args, **kwargs):
"""Initialize an ARC4 cipher object
See also `new()` at the module level."""
if len(args) > 0:
ndrop = args[0]
args = args[1:]
else:
ndrop = kwargs.pop('drop', 0)
if len(key) not in key_size:
raise ValueError("Incorrect ARC4 key length (%d bytes)" % len(key))
self._state = VoidPointer()
result = _raw_arc4_lib.ARC4_stream_init(c_uint8_ptr(key),
c_size_t(len(key)),
self._state.address_of())
if result != 0:
raise ValueError("Error %d while creating the ARC4 cipher" %
result)
self._state = SmartPointer(self._state.get(),
_raw_arc4_lib.ARC4_stream_destroy)
if ndrop > 0:
# This is OK even if the cipher is used for decryption,
# since encrypt and decrypt are actually the same thing
# with ARC4.
self.encrypt(b'\x00' * ndrop)
self.block_size = 1
self.key_size = len(key)
def __init__(self, data, truncate):
self._truncate = truncate
if truncate is None:
self.oid = "2.16.840.1.101.3.4.2.3"
self.digest_size = 64
elif truncate == "224":
self.oid = "2.16.840.1.101.3.4.2.5"
self.digest_size = 28
elif truncate == "256":
self.oid = "2.16.840.1.101.3.4.2.6"
self.digest_size = 32
else:
raise ValueError("Incorrect truncation length. It must be '224' or '256'.")
state = VoidPointer()
result = _raw_sha512_lib.SHA512_init(state.address_of(),
c_size_t(self.digest_size))
if result:
raise ValueError("Error %d while instantiating SHA-512"
% result)
self._state = SmartPointer(state.get(),
_raw_sha512_lib.SHA512_destroy)
if data:
self.update(data)
def encrypt(self, plaintext, output=None):
"""Encrypt data with the key set at initialization.
The data to encrypt can be broken up in two or
more pieces and `encrypt` can be called multiple times.
That is, the statement:
>>> c.encrypt(a) + c.encrypt(b)
is equivalent to:
>>> c.encrypt(a+b)
This function does not add any padding to the plaintext.
:Parameters:
plaintext : bytes/bytearray/memoryview
The piece of data to encrypt.
The length must be multiple of the cipher block length.
:Keywords:
output : bytearray/memoryview
The location where the ciphertext must be written to.
If ``None``, the ciphertext is returned.
:Return:
If ``output`` is ``None``, the ciphertext is returned as ``bytes``.
Otherwise, ``None``.
"""
if output is None:
ciphertext = create_string_buffer(len(plaintext))
else:
ciphertext = output
if not is_writeable_buffer(output):
raise TypeError(
"output must be a bytearray or a writeable memoryview")
if len(plaintext) != len(output):
raise ValueError(
"output must have the same length as the input"
" (%d bytes)" % len(plaintext))
result = raw_ecb_lib.ECB_encrypt(self._state.get(),
c_uint8_ptr(plaintext),
c_uint8_ptr(ciphertext),
c_size_t(len(plaintext)))
if result:
if result == 3:
raise ValueError(
"Data must be aligned to block boundary in ECB mode")
raise ValueError("Error %d while encrypting in ECB mode" % result)
if output is None:
return get_raw_buffer(ciphertext)
else:
return None
def __int__(self):
# buf will contain the integer encoded in decimal plus the trailing
# zero, and possibly the negative sign.
# dig10(x) < log10(x) + 1 = log2(x)/log2(10) + 1 < log2(x)/3 + 1
buf_len = _gmp.mpz_sizeinbase(self._mpz_p, 2) // 3 + 3
buf = create_string_buffer(buf_len)
_gmp.gmp_snprintf(buf, c_size_t(buf_len), b("%Zd"), self._mpz_p)
return int(get_c_string(buf))
def __init__(self, key, nonce):
"""Initialize a ChaCha20 cipher object
See also `new()` at the module level."""
self.nonce = _copy_bytes(None, None, nonce)
self._next = (self.encrypt, self.decrypt)
self._state = VoidPointer()
result = _raw_chacha20_lib.chacha20_init(self._state.address_of(),
c_uint8_ptr(key),
c_size_t(len(key)),
self.nonce,
c_size_t(len(nonce)))
if result:
raise ValueError("Error %d instantiating a ChaCha20 cipher")
self._state = SmartPointer(self._state.get(),
_raw_chacha20_lib.chacha20_destroy)
def _transcrypt_aligned(self, in_data, in_data_len, trans_func,
trans_desc):
out_data = create_string_buffer(in_data_len)
result = trans_func(self._state.get(), in_data, out_data,
c_size_t(in_data_len))
if result:
raise ValueError("Error %d while %sing in OCB mode" %
(result, trans_desc))
return get_raw_buffer(out_data)
def __init__(self, data=None):
state = VoidPointer()
result = _raw_keccak_lib.keccak_init(state.address_of(), c_size_t(32),
0x1F)
if result:
raise ValueError("Error %d while instantiating SHAKE128" % result)
self._state = SmartPointer(state.get(), _raw_keccak_lib.keccak_destroy)
self._is_squeezing = False
if data:
self.update(data)
def update(self, block_data):
assert len(block_data) % 16 == 0
result = self.ghash_c.ghash(self._last_y, c_uint8_ptr(block_data),
c_size_t(len(block_data)), self._last_y,
self._exp_key.get())
if result:
raise ValueError("Error %d while updating GHASH" % result)
return self
def xy(self):
modulus_bytes = self.size_in_bytes()
xb = bytearray(modulus_bytes)
yb = bytearray(modulus_bytes)
result = _ec_lib.ec_ws_get_xy(c_uint8_ptr(xb), c_uint8_ptr(yb),
c_size_t(modulus_bytes),
self._point.get())
if result:
raise ValueError("Error %d while encoding an EC point" % result)
return (Integer(bytes_to_long(xb)), Integer(bytes_to_long(yb)))
def from_bytes(byte_string):
"""Convert a byte string into a number.
:Parameters:
byte_string : byte string
The input number, encoded in network order.
It can only be non-negative.
:Return:
The ``Integer`` object carrying the same value as the input.
"""
result = Integer(0)
_gmp.mpz_import(
result._mpz_p,
c_size_t(len(byte_string)), # Amount of words to read
1, # Big endian
c_size_t(1), # Each word is 1 byte long
0, # Endianess within a word - not relevant
c_size_t(0), # No nails
byte_string)
return result
def update(self, data):
"""Continue hashing of a message by consuming the next chunk of data.
Args:
data (byte string/byte array/memoryview): The next chunk of the message being hashed.
"""
result = _raw_md2_lib.md2_update(self._state.get(), c_uint8_ptr(data),
c_size_t(len(data)))
if result:
raise ValueError("Error %d while instantiating MD2" % result)
def _encrypt(self, plaintext):
"""Encrypt without FSM checks"""
ciphertext = create_string_buffer(len(plaintext))
result = _raw_chacha20_lib.chacha20_encrypt(self._state.get(),
c_uint8_ptr(plaintext),
ciphertext,
c_size_t(len(plaintext)))
if result:
raise ValueError("Error %d while encrypting with ChaCha20" %
result)
return get_raw_buffer(ciphertext)
def strxor_c(term, c):
"""XOR of a byte string with a repeated sequence of characters.
Return:
A new byte string, :data:`term` with all its bytes xored with :data:`c`.
"""
if not 0 <= c < 256:
raise ValueError("c must be in range(256)")
result = create_string_buffer(len(term))
_raw_strxor.strxor_c(c_uint8_ptr(term), c, result, c_size_t(len(term)))
return get_raw_buffer(result)
def __init__(self, data, update_after_digest):
self._update_after_digest = update_after_digest
self._digest_done = False
state = VoidPointer()
result = _raw_keccak_lib.keccak_init(state.address_of(),
c_size_t(self.digest_size * 2),
0x06)
if result:
raise ValueError("Error %d while instantiating SHA-3/256" % result)
self._state = SmartPointer(state.get(), _raw_keccak_lib.keccak_destroy)
if data:
self.update(data)
def __init__(self, data, key, digest_bytes, update_after_digest):
# The size of the resulting hash in bytes.
self.digest_size = digest_bytes
self._update_after_digest = update_after_digest
self._digest_done = False
# See https://tools.ietf.org/html/rfc7693
if digest_bytes in (16, 20, 28, 32) and not key:
self.oid = "1.3.6.1.4.1.1722.12.2.2." + str(digest_bytes)
state = VoidPointer()
result = _raw_blake2s_lib.blake2s_init(state.address_of(),
c_uint8_ptr(key),
c_size_t(len(key)),
c_size_t(digest_bytes))
if result:
raise ValueError("Error %d while instantiating BLAKE2s" % result)
self._state = SmartPointer(state.get(),
_raw_blake2s_lib.blake2s_destroy)
if data:
self.update(data)
def __imul__(self, scalar):
"""Multiply this point by a scalar"""
if scalar < 0:
raise ValueError(
"Scalar multiplication is only defined for non-negative integers"
)
sb = long_to_bytes(scalar)
result = _ec_lib.ec_ws_scalar(self._point.get(), c_uint8_ptr(sb),
c_size_t(len(sb)),
c_ulonglong(getrandbits(64)))
if result:
raise ValueError("Error %d during scalar multiplication" % result)
return self
def to_bytes(self, block_size=0):
"""Convert the number into a byte string.
This method encodes the number in network order and prepends
as many zero bytes as required. It only works for non-negative
values.
:Parameters:
block_size : integer
The exact size the output byte string must have.
If zero, the string has the minimal length.
:Returns:
A byte string.
:Raise ValueError:
If the value is negative or if ``block_size`` is
provided and the length of the byte string would exceed it.
"""
if self < 0:
raise ValueError("Conversion only valid for non-negative numbers")
buf_len = (_gmp.mpz_sizeinbase(self._mpz_p, 2) + 7) // 8
if buf_len > block_size > 0:
raise ValueError("Number is too big to convert to byte string"
"of prescribed length")
buf = create_string_buffer(buf_len)
_gmp.mpz_export(
buf,
null_pointer, # Ignore countp
1, # Big endian
c_size_t(1), # Each word is 1 byte long
0, # Endianess within a word - not relevant
c_size_t(0), # No nails
self._mpz_p)
return bchr(0) * max(0, block_size - buf_len) + get_raw_buffer(buf)
def strxor(term1, term2):
"""XOR of two byte strings.
They must have equal length.
Return:
A new byte string, :data:`term1` xored with :data:`term2`.
"""
if len(term1) != len(term2):
raise ValueError("Only byte strings of equal length can be xored")
result = create_string_buffer(len(term1))
_raw_strxor.strxor(c_uint8_ptr(term1), c_uint8_ptr(term2), result,
c_size_t(len(term1)))
return get_raw_buffer(result)
def digest(self):
"""Return the **binary** (non-printable) digest of the message that has been hashed so far.
:return: The hash digest, computed over the data processed so far.
Binary form.
:rtype: byte string
"""
bfr = create_string_buffer(self.digest_size)
result = _raw_sha256_lib.SHA256_digest(self._state.get(), bfr,
c_size_t(self.digest_size))
if result:
raise ValueError("Error %d while making SHA256 digest" % result)
return get_raw_buffer(bfr)
def update(self, data):
"""Continue hashing of a message by consuming the next chunk of data.
Args:
data (byte string/array): The next chunk of the message being hashed.
"""
if self._digest_done and not self._update_after_digest:
raise TypeError("You can only call 'digest' or 'hexdigest' on this object")
result = _raw_blake2b_lib.blake2b_update(self._state.get(),
c_uint8_ptr(data),
c_size_t(len(data)))
if result:
raise ValueError("Error %d while hashing BLAKE2b data" % result)
return self
