Quantum effects

Rob Zuccherato sheds some light (but not photons) on what the availability of large-scale quantum computers might mean to existing cryptographic algorthyms and key sizes, as well as the practicality of quantum crypto.

...the limitations of quantum cryptography (e.g., a single continuous fibre or line of sight must exist between the two parties) suggest that it will only really be applicable to high security link encryption, and not necessarily to other current applications of cryptography.

In addition, quantum key distribution requires that a pre-existing authentic channel must exist between the two parties. Typically, this will be realized by the two parties having a pre-shared symmetric key that they can use for authentication.

Sounds like quantum crypto and OpenID is a marriage made in heaven.