Most of the current instant messaging applications such as Telegram Secret Chat transmit packets in plain text. This means that an intruder equipped with appropriate remote monitoring tools can sniff the packets being transmitted and obtain the raw packets that are being relayed across the network. However, some of them like Whatsapp and Facebook Messenger have embraced end –to-end encryption. In so doing, this encryption protects this data as it is being passed from one device to another over communication channels. Effectively, this prevents potential eavesdroppers such as telecommunication service providers, Internet service providers or the provider of the communication service from being able to access the cryptographic keys needed to decrypt the conversation. However, most messaging applications encrypt data but only between the user and the companies' servers. The consequence of this is that the service providers can pry open the data being passed across their network data anytime and access the information being passed between the communicating parties. This paper sought to develop a port-based algorithm for packet encapsulation in instant messaging sessions. This is in realization of the fact that even with end to end encryption, the instant messages are in plain text at the communicating devices. This means that eavesdropping can still happen if these instant messages are read by people other than the ones for which the communication was meant. A prototype instant messenger application was developed with end to end encryption in place, as well as message encryption at the end devices. In this way, only a party that has a decryption key can read the transmitted messages.