Looking for a way to generate an encrypted string (with salt) in C++ then send that string over to a java server and decrypt it on java as well. Any suggestions?

Algorithms aren't language dependent.
Find a secure one you like and implement it twice.

@Root 2nd rule of crypto: don't implement it yourself.

@zemaitis No, really. 1st rule of crypto is "don't roll out your own crypto", and 2nd is "don't implement it yourself". Find some reputable known-good libs and use them.

Here's a cheat sheet you can use: https://gist.github.com/tqbf/...

@zemaitis With? Choices?
Bcrypt comes to mind.

If you prefer large integers instead, I hear GPG is so nice that it's been banned in a few places.

Bouncycastle. Or smth from jdk libs. BC has a vide variety of algo implementations.

Dunno about c++. You can always use the same BC via JNI.

Since you are building a secret spaceship we have no details of - not much we can do.

AES? Probably the simplest option.

I would def go for AES unless you have some fancy requirements

Use standard libraries. Find one which exists in C++ and in Java.

@Root I don't think implementing it your self is a good idea