Entangled-state cryptographic protocol that remains secure even if   nonlocal hidden variables exist and can be measured with arbitrary precision
  Standard quantum cryptographic protocols are not secure if one assumes that nonlocal hidden variables exist and can be measured with arbitrary precision. The security can be restored if one of the communicating parties randomly switches between two standard protocols. 
Diederik Aerts, Marek Czachor, Marcin Pawlowski