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dS )z4Module with definitions common to all block ciphers.� N� � )�*� � � � � c C s6 |� | �}t|�|kr.|r&td| ��|| }|p4|S )zFFind a parameter in tuple and dictionary arguments a function receivesz!Parameter '%s' is specified twice)�get�len�
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| }d| _ |S | j�|�S )aX Encrypt data with the key and the parameters set at initialization.
The cipher object is stateful; encryption of a long block
of data can be broken up in two or more calls to `encrypt()`.
That is, the statement:
>>> c.encrypt(a) + c.encrypt(b)
is always 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 perform any padding.
- For `MODE_ECB`, `MODE_CBC`, and `MODE_OFB`, *plaintext* length
(in bytes) must be a multiple of *block_size*.
- For `MODE_CFB`, *plaintext* length (in bytes) must be a multiple
of *segment_size*/8.
- For `MODE_CTR`, *plaintext* can be of any length.
- For `MODE_OPENPGP`, *plaintext* must be a multiple of *block_size*,
unless it is the last chunk of the message.
:Parameters:
plaintext : byte string
The piece of data to encrypt.
:Return:
the encrypted data, as a byte string. It is as long as
*plaintext* with one exception: when encrypting the first message
chunk with `MODE_OPENPGP`, the encypted IV is prepended to the
returned ciphertext.
r �FOnly the last chunk is allowed to have length not multiple of %d bytesTr N) r r r r r! r r# r r$ r r% )r' Z plaintext�padding_length�padded�resr r r r$ � s '
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zBlockAlgo.encryptc C s� | j tkr~| jt|�| j | j }|dkrn| jr>td| j��d| _|td�| }| j�|�dt|�� }n | j�|�}|S | j�|�S )a� Decrypt data with the key and the parameters set at initialization.
The cipher object is stateful; decryption of a long block
of data can be broken up in two or more calls to `decrypt()`.
That is, the statement:
>>> c.decrypt(a) + c.decrypt(b)
is always equivalent to:
>>> c.decrypt(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 perform any padding.
- For `MODE_ECB`, `MODE_CBC`, and `MODE_OFB`, *ciphertext* length
(in bytes) must be a multiple of *block_size*.
- For `MODE_CFB`, *ciphertext* length (in bytes) must be a multiple
of *segment_size*/8.
- For `MODE_CTR`, *ciphertext* can be of any length.
- For `MODE_OPENPGP`, *plaintext* must be a multiple of *block_size*,
unless it is the last chunk of the message.
:Parameters:
ciphertext : byte string
The piece of data to decrypt.
:Return: the decrypted data (byte string, as long as *ciphertext*).
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__module__� __qualname__�__doc__r* r$ r& r r r r r � s 3;r )N)r2 �sys� version_infoZCrypto.Util.py21compatZCrypto.Util.py3compatr ZMODE_CBCr" ZMODE_PGPZMODE_OFBZMODE_CTRr r r r r r r �<module> s