I can’t find a suitable task for further development of network programming skills in C

Question

TLS

Hello! A few months ago, I decided to study network programming, GNU/Linux and cryptography, preferably both. Installing Gentoo and a few months of setup helped me figure out GNU/Linux. Studied basic networking theory (TCP/IP,UDP,... SSL/TLS, packet structure). Studied the BSD Socket API and the basics of cryptography (symmetric and asymmetric encryption, certificates/signatures). To consolidate my knowledge, I wrote in C a simple TCP / IP client and server that sends a character string using sockets. After some time of googling, I decided to move towards writing a sniffer. When writing it, I studied the structure of packages, what is SOCK_PACKET. But I still think it's not enough. I also wrote in C a client and server communicating over TLS 1.2 using a self-signed certificate, RSA key (OpenSSL library). I didn't find the tasks suitable for me on the net. Basically, tips for further development of the skill relate to adding additional functionality to simple client-server applications (add caching, handle multiple clients at the same time, add handles for errors). After googling, the only idea is to write your own sanbox (this is where C comes in handy and cryptography is possible), but this does not apply much to networks and a program like SSLstrip (for MITM attacks). I do not consider these ideas promising for infusion of energy (maybe I'm wrong?). handling multiple clients at the same time, add error handles). After googling, the only idea is to write your own sanbox (this is where C comes in handy and cryptography is possible), but this does not apply much to networks and a program like SSLstrip (for MITM attacks). I do not consider these ideas promising for infusion of energy (maybe I'm wrong?). handling multiple clients at the same time, add error handles). After googling, the only idea is to write your own sanbox (this is where C comes in handy and cryptography is possible), but this does not apply much to networks and a program like SSLstrip (for MITM attacks). I do not consider these ideas promising for infusion of energy (maybe I'm wrong?).
Tell me an example of a task (or resources where they can be found), which will be quite complex and preferably include network programming, C language, GNU / Linux and applied cryptography)
(purely as a hobby. I know English.)

Answer 1

write your vpn server or tor node