| Currently,the research of secure multi-party computations mainly focus on improving the complexity of protocols and striving to the implementation of specific security protocols,and secure multi-party computations are usually carried out on computer networks,one important question is always neglected: secure multi-party computations protocol over an underlying communication network whose structure might be,in itself,sensitive information.Exposure of the network topology could have severe privacy implications on nodes relationships or locations.On the other hand,there are the problems that sensitive information is intercepted in the process of transmission,and the subjects involved in the calculation are not completely trusted each other.While oblivious transfer can be used as a basic tool to solve these problems.In this paper,the oblivious transfer of data and the privacy protection of the underlying network communication structure are studied on basis of secure multi-party computation.The specified contents are shown below:(1)With the characteristics of NTRU asymmetric cryptosystem of easy key generation,fast encryption and decryption,and low storage requirements.Three secure as well as efficient oblivious transfer protocols are designed based on NTRU in this paper and compared with the oblivious transfer based on RSA and elliptic curves cryptography(ECC).Experimental results show that,compared with other similar protocols,these algorithms have faster execution efficiency and smaller communication load under the same safety condition.(2)Aiming at sensitive information such as nodes relationships and geographical positions,a topology hiding broadcast protocol scheme based on oblivious transfer is proposed combining the efficient NTRU public key encryption algorithm and oblivious transfer protocol.Firstly,leveraging on an untrusted server which helps adjacent nodes securely computing OR-operation of the broadcasts and keeps intermediate outcomes concealed for the sake of topological privacy.Secondly,solving the problems of secret key reconstruction,adjacent node identity concealment and dynamic changes in the network which are not yet involved in Tal Moran conceptual scheme.Finally,security and performance analysis indicated that the proposed protocol can endure topology concealment as long as any part of the network is corrupted,and manifest its merits of low computation and communication overheads as well as the advantage of their independence to node degree.(3)In accordance with the topology hiding broadcast protocol based NTRU oblivious transfer protocol under the condition that the server collides with any network nodes which may restore the intermediate data in each round and then get the orientation of message source,hops and other issues.Using the full homomorphic properties of Shamir secret sharing,a fast multiplication operation with only four rounds of interaction is achieved.A kind of highly efficient topology hiding broadcast scheme is constructed by using the idea of clustering and designing of the secret share updating algorithm.This scheme achieves a better improvement in computational efficiency and security than the topology-hiding broadcast protocol based on oblivious transfer.The innovation of this paper can be described as follows:(1)The protocol for oblivious transfer on the basis of NTRU public key encryption algorithm is proposed,and three kinds of scalable oblivious transfer protocol are designed.(2)According to a secure broadcast protocol for topology privacy protection proposed by Tal Moran in theory,a topology hiding broadcast scheme based on oblivious transfer is designed with the semi-homomorphic characteristics of improved NTRU encryption algorithm.(3)A secret share renewal technique is proposed to protect the Shamir(t,n)threshold security feature.And a more adaptive topology hiding scheme is put forward in accordance with the full homomorphic properties of Shamir secret sharing. |
PDF Full Text Request