An Application for secure email exchange: encryption-decryption with AES in ECB mode, including secure delivery of the secret key with RSA and signature based on EL-GAMAL, using the Hash function SHA-256

Running the Application

There are two ways to run the application : using mvn spring-boot:run or by running the Application class directly from your IDE.

Below are the configuration details to start the project using a spring-boot:run command. Both Eclipse and Intellij IDEA are covered.

Eclipse

• Right click on a project folder and select Run As --> Maven build.. . After that a configuration window is opened.
• In the window set the value of the Goals field to spring-boot:run
• You can optionally select Skip tests checkbox
• All the other settings can be left to default

Once configurations are set clicking Run will start the application

Intellij IDEA

• On the right side of the window, select Maven --> Plugins--> spring-boot --> spring-boot:run goal
• Optionally, you can disable tests by clicking on a Skip Tests mode blue button.

Clicking on the green run button will start the application.

After the application has started, you can view your it at http://localhost:9999/ in your browser.

(You can change the port from application.properties under src/main/resources. ( i.e. src/main/resources/application.properties)

If you want to run the application locally in the production mode, use spring-boot:run -Pproduction command instead.

Project overview

Project follow the Maven's directory layout structure:

• Under the srs/main/java/com.packagename.chat are located Application sources
  • Application.java is a runnable Java application class and a starting point
  • GreetService.java is a Spring service class
  • MainView.java is a default view and entry point of the application
  • User.java is a Model Class of a user
• Under the srs/main/java/DAO are located Application logic sources
  • DAO/AES.java is a service class with implementation of AES algorithm in ECB mode
  • DAO/ElGamalSignatureInstance.java is a service class with implementation of El Gamal algorithm of handling the digital signature
  • DAO/IRSA.java is an Interface of RSA algorithm
  • DAO/RSAImpl.javais a service class with implementation of RSA algorithm methods
  • DAO/Utils.java is a service util class for RSAImpl
• Under the srs/test are located test files
• src/main/resources contains configuration files and static resources
• The frontend directory in the root folder contains client-side dependencies and resource files
  • All CSS styles used by the application are located under the root directory frontend/styles
  • Templates would be stored under the frontend/src

Notes

If you run application from a command line, remember to prepend a mvn to the command.

Example

This is the login page:

There are 2 users in the system
user #1: username: Alice , password: 123
user #2: username: Bob , password: 123

---

After sending the message from Alice to Bob, this is what will be seen on Alice's screen:

---

After sending the message from Alice to Bob, this is what will be seen on Bob's screen:

---