  Methods of quantum mechanics promise information-theoretic security for
various protocols in cryptography. However, impossibility of some cryptographic
applications such as standard bit commitment, oblivious transfer, multiparty
secure computations and ideal coin tossing in quantum regime leaves an obvious
question on the completeness of quantum cryptography. Instead of using wide
range of rules and techniques for a variety of cryptographic applications, we
demonstrate here a unified structure for quantum cryptography based on quantum
non-local correlations. The unified framework achieves same goals in
information-theoretic way as classical cryptography does with computational
hardness. To cover the broad range of cryptographic applications, we show that
the framework (i) assures secrecy by providing encryption completely
unintelligible to eavesdroppers, (ii) guarantees that input from distant
parties is concealed unless they are willing to reveal, (iii) assures binding,
(iv) allows splitting information between several parties securely and more
generally, (v) evades both quantum and classical attacks from internal as well
as external eavesdropping.
