Secure Communication without Encryption?

The potential computational speedup that quantum algorithms offer in certain problems threatens the security of current cryptographic techniques that rely on the infeasibility of factoring large numbers. But the same technology that currently threatens public-key infrastructure also provides a seeming alternative: a protocol for quantum key distribution (QKD), which provides a secure method for establishing a secret key between two participants. These two people can then use this key to encrypt information, providing them with the ability to communicate securely