С++ Big integer for array and for rand [closed]

I implemented the cryptography method. But there is one thing. It works right for small values. I have a question, do I have any library so that I can use large integer variables? In addition, I need an array of such numbers and a rand function for large numbers. Maybe there's a library for that, or something like that? Implemented on C++. If there are ideas on how to do this in other languages, then please write. Thank you in advance.

I tried the InfInt library, but there is no way to make a large random number in it. These failures: https://faheel.github.io/BigInt/ https://github.com/rgroshanrg/bigint