Secure multi-party multiplication is a special secure multi-party computation problem, which can be used by multi-party to share the multiplication result. Present protocols frequently using the secure two-party multiplication protocol which has high communication cost and large amount of data. Based on the homomorphic encryption technology, a serial secure multi-party multiplication protocol in the complex communication environment and a parallel secure multi-party multiplication protocol in the ideal communication environment are presented for this problem in the semi-honest model.At last, correctness and security of those protocols are analyzed. Compared with the present protocols, the analysis shows that the proposed protocols have better advantages in the communication cost and the execution efficiency.
Secure multi-party multiplication is a special secure multi-party computation problem, which can be used by multi-party to share the multiplication result. Present protocols frequently using the secure two-party multiplication protocol which has high communication cost and large amount of data. Based on the homomorphic encryption technology, a serial secure multi-party multiplication protocol in the complex communication environment and a parallel secure multi-party multiplication protocol in the ideal communication environment are presented for this problem in the semi-honest model.At last, correctness and security of those protocols are analyzed. Compared with the present protocols, the analysis shows that the proposed protocols have better advantages in the communication cost and the execution efficiency.
Secure two-party comparing is a special case and a basic module of secure computations,and is applied in mobile code and e-commerce security etc.But known solutions have some disadvantages:expensive costs of computing and communicating,limited ranges of compared numbers.Based on a modified ElGamal algorithm,this paper presented and proved multiplicative,mixed-multiplicative,additive and subtractive homomorphic cryptosystem.Constructed an encrypted function unknown by two-party using the homomorphic cryptosystem.Based on the homomorphic cryptosystem and evaluation of encrypted functions,designed secure two-party comparing protocol under semi-honest model.Proof,example and comparing with other protocols show the proposed protocol has the merits of security,fairness,lower costs of communication and computational complexity,and comparing integers.
In this paper, the problem of secure two-party multiplication of shared secrets is considered, and it is one of problems of secure multi-party computation, where the policy for the shared secrets is based on polynomial interpolation. Firstly, a secure two-party protocol for polynomial multiplication is presented. Secondly, based on the first protocol, a protocol for secure two-party multiplication of shared secrets for semi-honest model is proposed, which is employed to multiply two shared secrets without revealing the private information of two parties. Furthermore, based on the definition of secure two-party computation and Composition Theorem, the proofs of security and analysis of the correctness and the complexity of our two protocols are given.
Secure multi-party computation has been playing a fundamental role in terms of classical cryptography. Quantum homomorphic encryption (QHE) could compute the encrypted data without decryption. At present, most protocols use a semi-honest third party (TP) to protect participants’ secrets. We use a quantum homomorphic encryption scheme instead of TP to protect the privacy of parties. Based on quantum homomorphic encryption, a secure multi-party quantum summation scheme is proposed in which N participants can delegate a server with strong quantum computing power to assist computation. By delegating the computation and key update processes to a server and a semi-honest key center, participants encrypt their private information data using Pauli operators to get the sum. Besides, the server can design and optimize the summation lines itself, and the correct results can be obtained even if the secret information is negative. The correctness analysis showed that the participants could correctly obtain the results of the calculation. The security analysis proves the scheme is resistant to both outside attack and participant’s attack, and is secure against collusive attack by up to N-2 participants. From the theoretical point of view, our protocol can extend to other secure multi-party computing problems.
An efficient two party RSA secret key sharing generation scheme based on a homomorphic encryption, which is semantically secure under the prime residuosity assumption, is proposed in this paper. At the stage of computing RSA modulo N , an initial distributed primality test protocol is used to reduce the computation complexity and increase the probability of N being a two-prime product. On the other aspect, the homomorphic encryption based sharing conversion protocols is devised and adopted in multi-party computing modulus N and secret key d . Comparing to any sharing conversion protocols based on oblivious transfer protocol, the homomorphic encryption based sharing conversion protocols are of high performance. Our scheme resists the passive attack and since a method of verifying the sharing was introduced in, the scheme can resists any cheating behaviors too. Security proof, computation complexity and communication complexity analysis are given at last.
Secure multi-party ranking is a problem generalized from the millionaires' problem,which can be used by n people to know about their secrets' order among all their inputs without leaking further information.Through the study on millionaires' protocol,we presented a secure two-party ranking protocol under semi-honest model based on homomorphic encryption.Then we generalized it to secure multi-party ranking,and we presented two algorithms whose efficiency are both improved.Finally,we gave a secure multi-party ranking protocol based on fuzzy nearness degree,and we analyzed the efficiency and security of these protocols.
Aiming at the problems of large ciphertext size and low efficiency in the current secure multi-party computation (SMC) protocol based on fully homomorphic encryption (FHE), the paper proves that the fully homomorphic encryption scheme that supports multi-bit encryption proposed by Chen Li et al. satisfies the key homomorphism. Based on this scheme and threshold decryption, a three-round, interactive, leveled, secure multi-party computation protocol under the Common Random String (CRS) model is designed. The protocol is proved to be safe under the semi-honest model and the semi-malicious model. From the non-interactive zero-knowledge proof, it can be concluded that the protocol is also safe under the malicious model. Its security can be attributed to the Decisional Learning With Errors (DLWE) and a variant of this problem (some-are-errorless LWE). Compared with the existing secure multi-party computation protocol based on fully homomorphic encryption under the CRS model, the ciphertext size of this protocol is smaller, the efficiency is higher, the storage overhead is smaller, and the overall performance is better than the existing protocol.