Suppose A and B are two computers on the network, and they are able to communicate. A has a need to occasionally send secret messages to B. However, the network channel is might be monitored by an attacker, and A does not want the attacker to know the messages. Design two methods to achieve this purpose. Encryption cannot be used. Suppose A and B are two computers on the network, and they are able to communicate. A has a need to occasionally send secret messages to B. However, the network channel is might be monitored by an attacker, and A does not want the attacker to know the messages. Design two methods to achieve this purpose. Encryption cannot be used