If you could give 10 years of development time to up to 10 software projects, which would you choose?
You can choose up to 10 software projects.
Each project receives 10 years of development time as if all the programmers worked continuously for that duration, following their current working methods.
After choosing these 10 (or less) projects, everything else remains unchanged in the world, as if time has been frozen for 10 years.
Well yeah but cryptography needs 2 things more than anything: variety and research. Variety so you can quickly switch ciphers if some vulnerability comes up, and research to publish those vulnerabilities so that bad actors aren't the only people who know about them.