We were tasked to develop a secure communication system between two client applications, through the use of a server. These clients are initially expected to exchange and validate each other’s certificates (which are issued by a Certification Authority trusted by both clients). The clients should then have the ability to communicate with each other by transmitting messages securely, by simulating the message confidentiality and authentication aspects of PGP (Pretty Good Privacy).
Requirement: Installation of bouncycastle
How to execute programs:
- Navigate to the directory: PGP_Prac
- Compile server class: javac ChatServer.java
- Compile client class: javac Client.java
- Run server class: java ChatServer
- [New terminal] Run first client class: java Client
- [New terminal] Run second client class: java Client
What to do next?
Setting up sender client: Prompt: 'Do you wish to (s)end or (r)receive messages:' Response: Type in 's' and click enter Prompt: 'Enter a username' Response: Enter username of your choice and hit enter Prompt: Do you wish to (c)reate or (j)oin a chat room: Response: Type in 'c' and hit enter Prompt: 'Chat room name:' Response: Enter chat room name of your choice and hit enter Prompt: 'Password:' Response: Enter chat room password of your choice and hit enter
NB: Before sending a message, ensure the receiver is set up and has joined the chat room
Setting up receiver client: Prompt: 'Do you wish to (s)end or (r)receive messages:' Response: Type in 'r' and click enter Prompt: 'Enter a username' Response: Enter username of your choice and hit enter Prompt: Do you wish to (c)reate or (j)oin a chat room: Response: Type in 'j' and hit enter Prompt: 'Chat room name:' Response: Enter name that was used by the sender client to create the chat room Prompt: 'Password:' Response: Enter password that was used by the sender client to create the chat room
Once the receiver has successfully joined the chat room, the sender can then send a message
[Sender client]: To send a message, the sender client must do the following: Prompt: 'Please enter a message to encrypt(/q to quit):' Response: Type in any message of your choice and hit enter
The PGP process involved with sending the message will now begin
[Receiver client] To receive a message, the receiver client must do the following: Prompt: 'Hit enter when ready to receive a message (/q to quit)' Response: Hit enter
The PGP process involved with receiving the message will now begin
'/q' can be entered to close the connection