That's great, but that's not what I'm telling you. I'm telling you not to develop and deploy them with human passengers, in a production environment, on a trip to orbit. If you get collaboration from professionals with significant expertise and audit the design and development extensively, then sure, go for it.
Even were that as accessible as developing and deploying your own cryptography, I'd still advise against it.
If you roll your own crypto and say, "that was a fun learning experience" and write a blog post about what you learned implementing AES in some novel way, nobody is going to show up and tell you not to roll your own crypto. If you roll your own crypto and then deploy it in a production system, then you are putting actual users at risk.
Even were that as accessible as developing and deploying your own cryptography, I'd still advise against it.