You are correct, but we're talking about asymmetric key crypto in general, not just encryption. Presumably the GP is referring to quantum-resistant hash-based s

You are correct, but we're talking about asymmetric key crypto in general, not just encryption. Presumably the GP is referring to quantum-resistant hash-based signature schemes such as https://en.wikipedia.org/wiki/Merkle_signature_scheme https://en.wikipedia.org/wiki/Merkle_signature_scheme