Harry Buhrman Nishanth Chandran Serge Fehr Ran Gelles Vipul Goyal Rafail Ostrovsky Christian Schaffner Position-Based Quantum Cryptography: Impossibility and Constructions. 429-446 2011 CRYPTO https://doi.org/10.1007/978-3-642-22792-9_24 conf/crypto/2011 db/conf/crypto/crypto2011.html#BuhrmanCFGGOS11