VirtIO Paravirtualized cryptographic character device for QEMU-KVM for Operating Systems Laboratory course of Electrical and Computer Engineering School of NTUA Athens. You can find the project code on GitHub

This exercise contains paradigm code for the implementation of a paravirtualized character device that exports the native /dev/crypto device of cryptodev to a QEMU VM.

• Client-server chat over TCP/IP sockets (/no_encryption)

For testing purposes, we first implement a simple chat system based on the client-server architecture, using TCP/IP UNIX sockets.

• Encrypted chat over TCP/IP sockets (/encryption)

Next, we added encryption functionality to the aforementioned client-server system. The implementation preserves the sockets API usage providing transparency and transmiting only the encrypted text over the socket. The implementation uses the native cryptodev /dev/crypto character device.

• Paravirtualized cryptographic driver device (/paravirt_encryption)

Using the client-server system implemented in the context of two QEMU virtual machines we faced serious performaace overhead, mainly from the cryptodev device that is also emulated. For this reason, we implemented a paravirtualized character device for each of the two guests that exposes the native /dev/crypto of the host.

The driver is composed of two parts, the frontend that is executed inside the character device driver of the guest and the backend that is executed in host userspace. Those two parts communicate usnig VirtIO paradigm principles.