A new commitment scheme based on position-verification and non-local quantum correlations is presented here for the first time in literature. The only credential for unconditional security is the position of committer and non-local correlations generated; neither receiver has any pre-shared data with the committer nor does receiver require trusted and authenticated quantum/classical channels between him and the committer. In the proposed scheme, receiver trusts the commitment only if the scheme itself verifies position of the committer and validates her commitment through non-local quantum correlations in a single round. The position-based commitment scheme bounds committer to reveal valid commitment within allocated time and guarantees that the receiver will not be able to get information about commitment unless committer reveals. The scheme works for the commitment of both bits and qubits and is equally secure against committer/receiver as well as against any third party who may have interests in destroying the commitment. Our proposed scheme is unconditionally secure in general and evades Mayers and Lo-Chau attacks in particular.
We propose here a two-round relativistic bit commitment scheme where committer commits in the first round and then confirms his/her commitment in the second round. The scheme offers indefinite commitment time where both committer and receiver extract non-locally correlated measurement outcomes during the scheme that can be stored and revealed after arbitrarily long time. We show that the proposed scheme turns out to be a multiparty bit commitment scheme where both parties commit and reveal simultaneously. The multiparty generalization would have applications in business and secure multiparty computations such as managing joint bank account, holding joint shares in stock exchange and blind bidding. The same bit commitment scheme can also be used for the commitment of arbitrarily long classical bit strings. The scheme can be applied efficiently with existing technologies; entanglement is required only for time t=x/c where x is the special distance, can be as small as possible, between the committer and receiver.
NTRU is a well-known public-key cryptosystem based on the difficulty of lattice reduction problems,and is mainly applied in public-key encryption and digital signature.This paper constructed a non-interactive and non-malleable commitment scheme,which relies the security on the intractable CVP on lattice,and the binding property of committer is satisfied.The validity of commitment is verified by hash function's collision resistance.Perturbing the plaintext with randomized mapping,plaintext will be in random distribution,and this scheme satisfies the hiding property of verifier and is non-malleable with respect to decommitment.This scheme has high efficiency as well as NTRU,and can resist channel eavesdropping attack,message replay attack and copying commitment attack.