I usually use something completely different for that use case. Specifically, ECDsaCng class from the standard library, which implements ECDSA asymmetric cryptoalgorithm.

Generate a key pair, embed public key in your executable, keep private key private.

A license is some JSON or XML or whatever, signed with the private key. If your licenses are permanent, and you don't need different license types, a license is just a signature of some computer ID (like hard drive serial), with that private key.

Unlike the older RSA, ECDSA results in very small signatures, even for very strong curves like NIST P-521. These signatures only take couple lines in Base64 text format.