rsa_aes.py 文件源码

def downstream_recv(self, data):
        try:
            enc=data.peek()
            if self._iv_dec is None: #receive IV
                if len(enc)<BLOCK_SIZE:
                    return
                self._iv_dec=enc[0:BLOCK_SIZE]
                if AES is not None:
                    self.dec_cipher = AES.new(self.aes_key, AES.MODE_CBC, self._iv_dec)
                else:
                    self.dec_cipher = pyaes.AESModeOfOperationCBC(self.aes_key, iv = self._iv_dec)
                data.drain(BLOCK_SIZE)
                enc=enc[BLOCK_SIZE:]
                if not enc:
                    return
            i=0
            cleartext=b""
            full_block=b""
            while True:
                if self.size_to_read is None:
                    if len(enc)<BLOCK_SIZE:
                        break
                    self.first_block=self.dec_cipher.decrypt(enc[0:BLOCK_SIZE])
                    data.drain(BLOCK_SIZE)
                    self.size_to_read=struct.unpack("<I", self.first_block[0:4])[0]
                    enc=enc[BLOCK_SIZE:]
                if self.size_to_read is None:
                    break
                if self.size_to_read <= len(self.first_block[4:]):
                    cleartext+=self.first_block[4:4+self.size_to_read] # the remaining data is padding, just drop it
                    self.size_to_read=None
                    self.first_block=b""
                    continue
                s=(self.size_to_read-len(self.first_block[4:]))
                blocks_to_read=s+(BLOCK_SIZE-(s%BLOCK_SIZE))
                if len(enc) < blocks_to_read:
                    break
                full_block=self.first_block[4:]+self.dec_cipher.decrypt(enc[:blocks_to_read])
                cleartext+=full_block[0:self.size_to_read] # the remaining data is padding, just drop it
                enc=enc[blocks_to_read:]
                data.drain(blocks_to_read)
                self.size_to_read=None
                self.first_block=b""
            self.upstream.write(cleartext)
        except Exception as e:
            logging.debug(traceback.format_exc())