A Quantum Copy-Protection Scheme with Authentication
  We propose a quantum copy-protection system which protects classical information in the form of non-orthogonal quantum states. The decryption of the stored information is not possible in the classical representation and the decryption mechanism of data qubits is realized by secret unitary rotations. We define an authentication method for the proposed copy-protection scheme and analyse the success probabilities of the authentication process. A possible experimental realization of the scheme is also presented. 
Laszlo Gyongyosi, Sandor Imre
quant-ph cs.IT math.IT