Python SmartPointer.address_of方法代码示例

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class _GHASH(object):
    """GHASH function defined in NIST SP 800-38D, Algorithm 2.

    If X_1, X_2, .. X_m are the blocks of input data, the function
    computes:

       X_1*H^{m} + X_2*H^{m-1} + ... + X_m*H

    in the Galois field GF(2^256) using the reducing polynomial
    (x^128 + x^7 + x^2 + x + 1).
    """

    def __init__(self, subkey):
        assert len(subkey) == 16

        expect_byte_string(subkey)
        self._exp_key = VoidPointer()
        result = _raw_galois_lib.ghash_expand(subkey,
                                              self._exp_key.address_of())
        if result:
            raise ValueError("Error %d while expanding the GMAC key" % result)

        self._exp_key = SmartPointer(self._exp_key.get(),
                                     _raw_galois_lib.ghash_destroy)

        self._last_y = create_string_buffer(16)
        for i in xrange(16):
            self._last_y[i] = bchr(0)

    def update(self, block_data):
        assert len(block_data) % 16 == 0

        expect_byte_string(block_data)
        result = _raw_galois_lib.ghash(self._last_y,
                                       block_data,
                                       c_size_t(len(block_data)),
                                       self._last_y,
                                       self._exp_key.get())
        if result:
            raise ValueError("Error %d while updating GMAC" % result)

        return self

    def digest(self):
        return get_raw_buffer(self._last_y)

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class _GHASH(object):
    """GHASH function defined in NIST SP 800-38D, Algorithm 2.

    If X_1, X_2, .. X_m are the blocks of input data, the function
    computes:

       X_1*H^{m} + X_2*H^{m-1} + ... + X_m*H

    in the Galois field GF(2^256) using the reducing polynomial
    (x^128 + x^7 + x^2 + x + 1).
    """

    def __init__(self, subkey, ghash_c):
        assert len(subkey) == 16

        self.ghash_c = ghash_c

        self._exp_key = VoidPointer()
        result = ghash_c.ghash_expand(c_uint8_ptr(subkey),
                                      self._exp_key.address_of())
        if result:
            raise ValueError("Error %d while expanding the GHASH key" % result)

        self._exp_key = SmartPointer(self._exp_key.get(),
                                     ghash_c.ghash_destroy)

        # create_string_buffer always returns a string of zeroes
        self._last_y = create_string_buffer(16)

    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 digest(self):
        return get_raw_buffer(self._last_y)

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class CtrMode(object):
    """*CounTeR (CTR)* mode.

    This mode is very similar to ECB, in that
    encryption of one block is done independently of all other blocks.

    Unlike ECB, the block *position* contributes to the encryption
    and no information leaks about symbol frequency.

    Each message block is associated to a *counter* which
    must be unique across all messages that get encrypted
    with the same key (not just within the same message).
    The counter is as big as the block size.

    Counters can be generated in several ways. The most
    straightword one is to choose an *initial counter block*
    (which can be made public, similarly to the *IV* for the
    other modes) and increment its lowest **m** bits by one
    (modulo *2^m*) for each block. In most cases, **m** is
    chosen to be half the block size.

    See `NIST SP800-38A`_, Section 6.5 (for the mode) and
    Appendix B (for how to manage the *initial counter block*).

    .. _`NIST SP800-38A` : http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf

    :undocumented: __init__
    """

    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 encrypt(self, plaintext):
        """Encrypt data with the key and the parameters set at initialization.

        A cipher object is stateful: once you have encrypted a message
        you cannot encrypt (or decrypt) another message using the same
        object.

        The data to encrypt can be broken up in two or
        more pieces and `encrypt` can be called multiple times.
#.........这里部分代码省略.........

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class ChaCha20Cipher:
    """ChaCha20 cipher object. Do not create it directly. Use :py:func:`new` instead.

    :var nonce: The nonce with length 8 or 12
    :vartype nonce: byte string
    """

    block_size = 1

    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 encrypt(self, plaintext):
        """Encrypt a piece of data.

        :param plaintext: The data to encrypt, of any size.
        :type plaintext: bytes, bytearray, memoryview
        :returns: the encrypted byte string, of equal length as the
          plaintext.
        """

        if self.encrypt not in self._next:
            raise TypeError("Cipher object can only be used for decryption")
        self._next = ( self.encrypt, )
        return self._encrypt(plaintext)

    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 decrypt(self, ciphertext):
        """Decrypt a piece of data.

        :param ciphertext: The data to decrypt, of any size.
        :type ciphertext: bytes, bytearray, memoryview
        :returns: the decrypted byte string, of equal length as the
          ciphertext.
        """

        if self.decrypt not in self._next:
            raise TypeError("Cipher object can only be used for encryption")
        self._next = ( self.decrypt, )

        try:
            return self._encrypt(ciphertext)
        except ValueError as e:
            raise ValueError(str(e).replace("enc", "dec"))

    def seek(self, position):
        """Seek to a certain position in the key stream.

        :param integer position:
            The absolute position within the key stream, in bytes.
        """

        position, offset = divmod(position, 64)
        block_low = position & 0xFFFFFFFF
        block_high = position >> 32

        result = _raw_chacha20_lib.chacha20_seek(
                                                 self._state.get(),
                                                 c_ulong(block_high),
                                                 c_ulong(block_low),
                                                 offset
                                                 )
        if result:
            raise ValueError("Error %d while seeking with ChaCha20" % result)

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class ARC4Cipher:
    """ARC4 cipher object"""

    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))

        expect_byte_string(key)

        self._state = VoidPointer()
        result = _raw_arc4_lib.ARC4_stream_init(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 encrypt(self, plaintext):
        """Encrypt a piece of data.

        :Parameters:
          plaintext : byte string
            The piece of data to encrypt. It can be of any size.
        :Return: the encrypted data (byte string, as long as the
          plaintext).
        """

        expect_byte_string(plaintext)
        ciphertext = create_string_buffer(len(plaintext))
        result = _raw_arc4_lib.ARC4_stream_encrypt(self._state.get(),
                                                   plaintext,
                                                   ciphertext,
                                                   c_size_t(len(plaintext)))
        if result:
            raise ValueError("Error %d while encrypting with RC4" % result)
        return get_raw_buffer(ciphertext)

    def decrypt(self, ciphertext):
        """Decrypt a piece of data.

        :Parameters:
          ciphertext : byte string
            The piece of data to decrypt. It can be of any size.
        :Return: the decrypted data (byte string, as long as the
          ciphertext).
        """
        try:
            return self.encrypt(ciphertext)
        except ValueError, e:
            raise ValueError(str(e).replace("enc", "dec"))

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class OcbMode(object):
    """Offset Codebook (OCB) mode.

    :undocumented: __init__
    """

    def __init__(self, factory, nonce, mac_len, cipher_params):

        if factory.block_size != 16:
            raise ValueError("OCB mode is only available for ciphers"
                             " that operate on 128 bits blocks")

        self.block_size = 16
        """The block size of the underlying cipher, in bytes."""

        self.nonce = nonce
        """Nonce used for this session."""
        if len(nonce) not in range(1, 16):
            raise ValueError("Nonce must be at most 15 bytes long")

        self._mac_len = mac_len
        if not 8 <= mac_len <= 16:
            raise ValueError("MAC tag must be between 8 and 16 bytes long")

        # Cache for MAC tag
        self._mac_tag = None

        # Cache for unaligned associated data
        self._cache_A = b("")

        # Cache for unaligned ciphertext/plaintext
        self._cache_P = b("")

        # Allowed transitions after initialization
        self._next = [self.update, self.encrypt, self.decrypt,
                      self.digest, self.verify]

        # Compute Offset_0
        params_without_key = dict(cipher_params)
        key = params_without_key.pop("key")
        nonce = (bchr(self._mac_len << 4 & 0xFF) +
                 bchr(0) * (14 - len(self.nonce)) +
                 bchr(1) +
                 self.nonce)
        bottom = bord(nonce[15]) & 0x3F   # 6 bits, 0..63
        ktop = factory.new(key, factory.MODE_ECB, **params_without_key)\
                      .encrypt(nonce[:15] + bchr(bord(nonce[15]) & 0xC0))
        stretch = ktop + strxor(ktop[:8], ktop[1:9])    # 192 bits
        offset_0 = long_to_bytes(bytes_to_long(stretch) >>
                                 (64 - bottom), 24)[8:]

        # Create low-level cipher instance
        raw_cipher = factory._create_base_cipher(cipher_params)
        if cipher_params:
            raise TypeError("Unknown keywords: " + str(cipher_params))

        self._state = VoidPointer()
        result = _raw_ocb_lib.OCB_start_operation(raw_cipher.get(),
                                                  offset_0,
                                                  c_size_t(len(offset_0)),
                                                  self._state.address_of())
        if result:
            raise ValueError("Error %d while instantiating the OCB 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_ocb_lib.OCB_stop_operation)

        # Memory allocated for the underlying block cipher is now owed
        # by the cipher mode
        raw_cipher.release()

    def _update(self, assoc_data, assoc_data_len):
        expect_byte_string(assoc_data)
        result = _raw_ocb_lib.OCB_update(self._state.get(),
                                         assoc_data,
                                         c_size_t(assoc_data_len))
        if result:
            raise ValueError("Error %d while MAC-ing in OCB mode" % result)

    def update(self, assoc_data):
        """Process the associated data.

        If there is any associated data, the caller has to invoke
        this method one or more times, before using
        ``decrypt`` or ``encrypt``.

        By *associated data* it is meant any data (e.g. packet headers) that
        will not be encrypted and will be transmitted in the clear.
        However, the receiver shall still able to detect modifications.

        If there is no associated data, this method must not be called.

        The caller may split associated data in segments of any size, and
        invoke this method multiple times, each time with the next segment.

        :Parameters:
          assoc_data : byte string
#.........这里部分代码省略.........

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class EcbMode(object):
    """*Electronic Code Book (ECB)*.

    This is the simplest encryption mode. Each of the plaintext blocks
    is directly encrypted into a ciphertext block, independently of
    any other block.

    This mode is dangerous because it exposes frequency of symbols
    in your plaintext. Other modes (e.g. *CBC*) should be used instead.

    See `NIST SP800-38A`_ , Section 6.1.

    .. _`NIST SP800-38A` : http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf

    :undocumented: __init__
    """

    def __init__(self, block_cipher):
        """Create a new block cipher, configured in ECB mode.

        :Parameters:
          block_cipher : C pointer
            A smart pointer to the low-level block cipher instance.
        """

        self._state = VoidPointer()
        result = raw_ecb_lib.ECB_start_operation(block_cipher.get(),
                                                 self._state.address_of())
        if result:
            raise ValueError("Error %d while instatiating the ECB 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_ecb_lib.ECB_stop_operation)

        # Memory allocated for the underlying block cipher is now owned
        # by the cipher mode
        block_cipher.release()

    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 decrypt(self, ciphertext, output=None):
        """Decrypt data with the key set at initialization.

#.........这里部分代码省略.........

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class CbcMode(object):
    """*Cipher-Block Chaining (CBC)*.

    Each of the ciphertext blocks depends on the current
    and all previous plaintext blocks.

    An Initialization Vector (*IV*) is required.

    See `NIST SP800-38A`_ , Section 6.2 .

    .. _`NIST SP800-38A` : http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf

    :undocumented: __init__
    """

    def __init__(self, block_cipher, iv):
        """Create a new block cipher, configured in CBC mode.

        :Parameters:
          block_cipher : C pointer
            A smart pointer to the low-level block cipher instance.

          iv : byte string
            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.
        """

        expect_byte_string(iv)
        self._state = VoidPointer()
        result = raw_cbc_lib.CBC_start_operation(block_cipher.get(),
                                                 iv,
                                                 c_size_t(len(iv)),
                                                 self._state.address_of())
        if result:
            raise ValueError("Error %d while instatiating the CBC 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_cbc_lib.CBC_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 = iv
        """The Initialization Vector originally used to create the object.
        The value does not change."""

        self.IV = iv
        """Alias for `iv`"""

        self._next = [ self.encrypt, self.decrypt ]

    def encrypt(self, plaintext):
        """Encrypt data with the key and the parameters set at initialization.

        A cipher object is stateful: once you have encrypted a message
        you cannot encrypt (or decrypt) another message using the same
        object.

        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)

        That also means that you cannot reuse an object for encrypting
        or decrypting other data with the same key.

        This function does not add any padding to the plaintext.

        :Parameters:
          plaintext : byte string
            The piece of data to encrypt.
            Its lenght must be multiple of the cipher block size.
        :Return:
            the encrypted data, as a byte string.
            It is as long as *plaintext*.
        """

        if self.encrypt not in self._next:
            raise TypeError("encrypt() cannot be called after decrypt()")
        self._next = [ self.encrypt ]

        expect_byte_string(plaintext)
#.........这里部分代码省略.........

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class Salsa20Cipher:
    """Salsa20 cipher object"""

    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))

        #: Nonce
        self.nonce = nonce

        expect_byte_string(key)
        expect_byte_string(nonce)

        self._state = VoidPointer()
        result = _raw_salsa20_lib.Salsa20_stream_init(
                        key,
                        c_size_t(len(key)),
                        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 encrypt(self, plaintext):
        """Encrypt a piece of data.

        :Parameters:
          plaintext : byte string
            The piece of data to encrypt. It can be of any size.
        :Return: the encrypted data (byte string, as long as the
          plaintext).
        """

        expect_byte_string(plaintext)
        ciphertext = create_string_buffer(len(plaintext))
        result = _raw_salsa20_lib.Salsa20_stream_encrypt(
                                         self._state.get(),
                                         plaintext,
                                         ciphertext,
                                         c_size_t(len(plaintext)))
        if result:
            raise ValueError("Error %d while encrypting with Salsa20" % result)
        return get_raw_buffer(ciphertext)

    def decrypt(self, ciphertext):
        """Decrypt a piece of data.

        :Parameters:
          ciphertext : byte string
            The piece of data to decrypt. It can be of any size.
        :Return: the decrypted data (byte string, as long as the
          ciphertext).
        """

        try:
            return self.encrypt(ciphertext)
        except ValueError, e:
            raise ValueError(str(e).replace("enc", "dec"))

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class OfbMode(object):
    """*Output FeedBack (OFB)*.

    This mode is very similar to CBC, but it
    transforms the underlying block cipher into a stream cipher.

    The keystream is the iterated block encryption of the
    previous ciphertext block.

    An Initialization Vector (*IV*) is required.

    See `NIST SP800-38A`_ , Section 6.4.

    .. _`NIST SP800-38A` : http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf

    :undocumented: __init__
    """

    def __init__(self, block_cipher, iv):
        """Create a new block cipher, configured in OFB 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 a nonce, to to be reused for any other
            message**. It shall be a nonce or a random value.

            Reusing the *IV* for encryptions performed with the same key
            compromises confidentiality.
        """

        self._state = VoidPointer()
        result = raw_ofb_lib.OFB_start_operation(block_cipher.get(),
                                                 c_uint8_ptr(iv),
                                                 c_size_t(len(iv)),
                                                 self._state.address_of())
        if result:
            raise ValueError("Error %d while instatiating the OFB 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_ofb_lib.OFB_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 encrypt(self, plaintext, output=None):
        """Encrypt data with the key and the parameters set at initialization.

        A cipher object is stateful: once you have encrypted a message
        you cannot encrypt (or decrypt) another message using the same
        object.

        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.
            It can be of any 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 self.encrypt not in self._next:
#.........这里部分代码省略.........

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class CfbMode(object):
    """*Cipher FeedBack (CFB)*.

    This mode is similar to CFB, but it transforms
    the underlying block cipher into a stream cipher.

    Plaintext and ciphertext are processed in *segments*
    of **s** bits. The mode is therefore sometimes
    labelled **s**-bit CFB.

    An Initialization Vector (*IV*) is required.

    See `NIST SP800-38A`_ , Section 6.3.

    .. _`NIST SP800-38A` : http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf

    :undocumented: __init__
    """

    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 encrypt(self, plaintext):
        """Encrypt data with the key and the parameters set at initialization.

        A cipher object is stateful: once you have encrypted a message
        you cannot encrypt (or decrypt) another message using the same
        object.

        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.
            It can be of any length.
        :Return:
            the encrypted data, as a byte string.
            It is as long as *plaintext*.
        """

        if self.encrypt not in self._next:
            raise TypeError("encrypt() cannot be called after decrypt()")
#.........这里部分代码省略.........

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class ARC4Cipher:
    """ARC4 cipher object. Do not create it directly. Use
    :func:`Cryptodome.Cipher.ARC4.new` instead.
    """

    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 encrypt(self, plaintext):
        """Encrypt a piece of data.

        :param plaintext: The data to encrypt, of any size.
        :type plaintext: bytes, bytearray, memoryview
        :returns: the encrypted byte string, of equal length as the
          plaintext.
        """

        ciphertext = create_string_buffer(len(plaintext))
        result = _raw_arc4_lib.ARC4_stream_encrypt(self._state.get(),
                                                   c_uint8_ptr(plaintext),
                                                   ciphertext,
                                                   c_size_t(len(plaintext)))
        if result:
            raise ValueError("Error %d while encrypting with RC4" % result)
        return get_raw_buffer(ciphertext)

    def decrypt(self, ciphertext):
        """Decrypt a piece of data.

        :param ciphertext: The data to decrypt, of any size.
        :type ciphertext: bytes, bytearray, memoryview
        :returns: the decrypted byte string, of equal length as the
          ciphertext.
        """

        try:
            return self.encrypt(ciphertext)
        except ValueError as e:
            raise ValueError(str(e).replace("enc", "dec"))

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class ChaCha20Cipher:
    """ChaCha20 cipher object"""

    block_size = 1

    def __init__(self, key, nonce):
        """Initialize a ChaCha20 cipher object

        See also `new()` at the module level."""

        expect_byte_string(key)
        expect_byte_string(nonce)

        self.nonce = nonce

        self._next = ( self.encrypt, self.decrypt )
        self._state = VoidPointer()
        result = _raw_chacha20_lib.chacha20_init(
                        self._state.address_of(),
                        key,
                        c_size_t(len(key)),
                        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 encrypt(self, plaintext):
        """Encrypt a piece of data.

        :Parameters:
          plaintext : byte string
            The piece of data to encrypt. It can be of any size.
        :Return: the encrypted data (byte string, as long as the
          plaintext).
        """

        if self.encrypt not in self._next:
            raise TypeError("Cipher object can only be used for decryption")
        self._next = ( self.encrypt, )
        return self._encrypt(plaintext)

    def _encrypt(self, plaintext):
        """Encrypt without FSM checks"""

        expect_byte_string(plaintext)
        ciphertext = create_string_buffer(len(plaintext))
        result = _raw_chacha20_lib.chacha20_encrypt(
                                         self._state.get(),
                                         plaintext,
                                         ciphertext,
                                         c_size_t(len(plaintext)))
        if result:
            raise ValueError("Error %d while encrypting with ChaCha20" % result)
        return get_raw_buffer(ciphertext)

    def decrypt(self, ciphertext):
        """Decrypt a piece of data.

        :Parameters:
          ciphertext : byte string
            The piece of data to decrypt. It can be of any size.
        :Return: the decrypted data (byte string, as long as the
          ciphertext).
        """

        if self.decrypt not in self._next:
            raise TypeError("Cipher object can only be used for encryption")
        self._next = ( self.decrypt, )

        try:
            return self._encrypt(ciphertext)
        except ValueError, e:
            raise ValueError(str(e).replace("enc", "dec"))

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class Salsa20Cipher:
    """Salsa20 cipher object. Do not create it directly. Use :py:func:`new`
    instead.

    :var nonce: The nonce with length 8
    :vartype nonce: byte string
    """

    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 encrypt(self, plaintext, output=None):
        """Encrypt a piece of data.

        Args:
          plaintext(bytes/bytearray/memoryview): The data to encrypt, of any size.
        Keyword Args:
          output(bytes/bytearray/memoryview): The location where the ciphertext
            is written to. If ``None``, the ciphertext is returned.
        Returns:
          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_salsa20_lib.Salsa20_stream_encrypt(
                                         self._state.get(),
                                         c_uint8_ptr(plaintext),
                                         c_uint8_ptr(ciphertext),
                                         c_size_t(len(plaintext)))
        if result:
            raise ValueError("Error %d while encrypting with Salsa20" % result)

        if output is None:
            return get_raw_buffer(ciphertext)
        else:
            return None

    def decrypt(self, ciphertext, output=None):
        """Decrypt a piece of data.
        
        Args:
          ciphertext(bytes/bytearray/memoryview): The data to decrypt, of any size.
        Keyword Args:
          output(bytes/bytearray/memoryview): The location where the plaintext
            is written to. If ``None``, the plaintext is returned.
        Returns:
          If ``output`` is ``None``, the plaintext is returned as ``bytes``.
          Otherwise, ``None``.
        """

        try:
            return self.encrypt(ciphertext, output=output)
        except ValueError as e:
            raise ValueError(str(e).replace("enc", "dec"))

# 需要导入模块: from Cryptodome.Util._raw_api import SmartPointer [as 别名]
# 或者: from Cryptodome.Util._raw_api.SmartPointer import address_of [as 别名]
class EcbMode(object):
    """*Electronic Code Book (ECB)*.

    This is the simplest encryption mode. Each of the plaintext blocks
    is directly encrypted into a ciphertext block, independently of
    any other block.

    This mode is dangerous because it exposes frequency of symbols
    in your plaintext. Other modes (e.g. *CBC*) should be used instead.

    See `NIST SP800-38A`_ , Section 6.1.

    .. _`NIST SP800-38A` : http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf

    :undocumented: __init__
    """

    def __init__(self, block_cipher):
        """Create a new block cipher, configured in ECB mode.

        :Parameters:
          block_cipher : C pointer
            A smart pointer to the low-level block cipher instance.
        """

        self._state = VoidPointer()
        result = raw_ecb_lib.ECB_start_operation(block_cipher.get(),
                                                 self._state.address_of())
        if result:
            raise ValueError("Error %d while instatiating the ECB 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_ecb_lib.ECB_stop_operation)

        # Memory allocated for the underlying block cipher is now owned
        # by the cipher mode
        block_cipher.release()

    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 : byte string
            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*.
        """

        expect_byte_string(plaintext)
        ciphertext = create_string_buffer(len(plaintext))
        result = raw_ecb_lib.ECB_encrypt(self._state.get(),
                                         plaintext,
                                         ciphertext,
                                         c_size_t(len(plaintext)))
        if result:
            raise ValueError("Error %d while encrypting in ECB mode" % result)
        return get_raw_buffer(ciphertext)

    def decrypt(self, ciphertext):
        """Decrypt data with the key set at initialization.

        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 : byte string
            The piece of data to decrypt.
            The length must be multiple of the cipher block length.

        :Return:
            the decrypted data (byte string).
#.........这里部分代码省略.........