def encrypt(self, plaintext):
        """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.
        """

        if self.mode == MODE_OPENPGP:
            padding_length = (self.block_size - len(plaintext) % self.block_size) % self.block_size
            if padding_length>0:
                # CFB mode requires ciphertext to have length multiple of block size,
                # but PGP mode allows the last block to be shorter
                if self._done_last_block:
                    raise ValueError("Only the last chunk is allowed to have length not multiple of %d bytes",
                        self.block_size)
                self._done_last_block = True
                padded = plaintext + b('\x00')*padding_length
                res = self._cipher.encrypt(padded)[:len(plaintext)]
            else:
                res = self._cipher.encrypt(plaintext)
            if not self._done_first_block:
                res = self._encrypted_IV + res
                self._done_first_block = True
            return res

        return self._cipher.encrypt(plaintext)
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/pycrypto-2.6.1/lib/Crypto/Cipher/blockalgo.py/BlockAlgo.encrypt/original