NEXT Coding

How does the project look like: A Java App is installed on our customers PC. We extend that Java App with our own classes to enable advanced features. We are searching for someone to develop C#/C++ components, that will download those classes from our microservices on demand and start the original Java App, then put our classes in the desired class paths. As the Java App works with confidential data, securing those must be the highest priority. What we need: 1. A C#/C++ UI that only does the basic things and requests any data from a Windows Service 2. The Windows Service, a C#/C++ middleware, that must function as a blackbox and must not leak any data. It shall be used for communicating with our microservices (SSL/encrypted data) What does the program flow look like: 1. User buys something in our shop 2. We will create the user credentials in our keycloak service and add extended permissions to our microservice for user permissions. Maybe we will integrate that into our keycloak service. Thats not final at this point 3. The user launches our launcher 4. The launcher checks if there is an update for it and the middleware. If yes, update is enforced 5. The user may login into our Windows UI and, if he is not banned/disabled, configure the path to the original Java App. 6. The user may launch the Java app via our Launcher 7. The middleware takes the users permission, downloads the JARS linked to those permissions, unpacks them and starts the original Java app with our classes put into the appropriate classpath. It also downloaded confidential data that the java app will be working with while running. That data must be available via a callable function from java class to the middleware. The running Java app must absolutely be secure against tampering. That means, that no data may be leaked. By data, we mean the data that is loaded from our microservices, so the java classes and other confidential data. So any data must not be saved physically on the drive (maybe a secure virtual file library?). We had another project in which we verified any loaded Java class via MD5 checksum and analyzed the call stack to be sure that the caller is our own code. Those security features can be up to the developer as long as there is no way that any data can be read our through modified code/modified JVM/etc. After the Java Programm exits, the confidential data + jars/classes must be removed and not leave any traces. This makes also sure, that our java classes are always the latest ones when launched. If MD5 is used to verify all classes to be not modified, we must be able to configure these MD5s if we make bug fixes within the classes.