RSA requires a lot of big primes to exist (so the search space is large), but doesn't require infinitely many. For each key size there's a maximum prime size t

RSA requires a lot of big primes to exist (so the search space is large), but doesn't require infinitely many. For each key size there's a maximum prime size that matters, and all RSA cryptography that's used in practice would work fine if there were, say, no primes with more than a million digits.