def _activate_outbound(self):
m = Message()<EOL>m.add_byte(cMSG_NEWKEYS)<EOL>self._send_message(m)<EOL>block_size = self._cipher_info[self.local_cipher]["<STR_LIT>"]<EOL>if self.server_mode:<EOL><INDENT>IV_out = self._compute_key("<STR_LIT:B>", block_size)<EOL>key_out = self._compute_key(<EOL>"<STR_LIT:D>", self._cipher_info[self.local_cipher]["<STR_LIT>"]<EOL>)<EOL><DEDENT>else:<EOL><INDENT>IV_out = self._compute_key("<STR_LIT:A>", block_size)<EOL>key_out = self._compute_key(<EOL>"<STR_LIT:C>", self._cipher_info[self.local_cipher]["<STR_LIT>"]<EOL>)<EOL><DEDENT>engine = self._get_cipher(<EOL>self.local_cipher, key_out, IV_out, self._ENCRYPT<EOL>)<EOL>mac_size = self._mac_info[self.local_mac]["<STR_LIT:size>"]<EOL>mac_engine = self._mac_info[self.local_mac]["<STR_LIT:class>"]<EOL>if self.server_mode:<EOL><INDENT>mac_key = self._compute_key("<STR_LIT:F>", mac_engine().digest_size)<EOL><DEDENT>else:<EOL><INDENT>mac_key = self._compute_key("<STR_LIT:E>", mac_engine().digest_size)<EOL><DEDENT>sdctr = self.local_cipher.endswith("<STR_LIT>")<EOL>self.packetizer.set_outbound_cipher(<EOL>engine, block_size, mac_engine, mac_size, mac_key, sdctr<EOL>)<EOL>compress_out = self._compression_info[self.local_compression][<NUM_LIT:0>]<EOL>if compress_out is not None and (<EOL>self.local_compression != "<STR_LIT>" or self.authenticated<EOL>):<EOL><INDENT>self._log(DEBUG, "<STR_LIT>")<EOL>self.packetizer.set_outbound_compressor(compress_out())<EOL><DEDENT>if not self.packetizer.need_rekey():<EOL><INDENT>self.in_kex = False<EOL><DEDENT>self._expect_packet(MSG_NEWKEYS)<EOL>
switch on newly negotiated encryption parameters for
         outbound traffic