To resist the fast algebraic attack and fast selective discrete Fourier transform attacks,spectral immunity of a sequence or a Boolean function was proposed.At the same time,an algorithm to compute the spectral immunity of the binary sequence with odd period N was presented,here N is a factor of 2^n-1,where n is an integer.The case is more complicated when the period is even.In this paper,we compute linear complexity of every orthogonal sequence of a given sequence using Chan-Games algorithm and k-error linear complexity algorithm.Then,an algorithm for spectral immunity of binary sequence with period N=2^n is obtained.Furthermore,the time complexity of this algorithm is proved to be O（n）.
We present a protocol for quantum private comparison of equality(QPCE) with the help of a semi-honest third party(TP).Instead of employing the entanglement,we use single photons to achieve the comparison in this protocol.By utilizing collective eavesdropping detection strategy,our protocol has the advantage of higher qubit efficiency and lower cost of implementation.In addition to this protocol,we further introduce three robust versions which can be immune to collective dephasing noise,collective-rotation noise and all types of unitary collective noise,respectively.Finally,we show that our protocols can be secure against the attacks from both the outside eavesdroppers and the inside participants by using the theorems on quantum operation discrimination.
We present two novel quantum secure direct communication（QSDC） protocols over different collective-noise channels.Different from the previous QSDC schemes over collective-noise channels,which are all source-encrypting protocols,our two protocols are based on channel-encryption.In both schemes,two authorized users first share a sequence of EPR pairs as their reusable quantum key.Then they use their quantum key to encrypt and decrypt the secret message carried by the decoherence-free states over the collective-noise channel.In theory,the intrinsic efficiencies of both protocols are high since there is no need to consume any entangled states including both the quantum key and the information carriers except the ones used for eavesdropping checks.For checking eavesdropping,the two parties only need to perform two-particle measurements on the decoy states during each round.Finally,we make a security analysis of our two protocols and demonstrate that they are secure.
Multi-proxy signature is a scheme that an original signer delegates his or her signing capability to a proxy group. In the scheme, only the cooperation of all proxy signers in the proxy group can create a signature on behalf of the original signer. Jin and Wen firstly defined the formal security model of certificateless multi-proxy signature （CLMPS） and proposed a concrete CLMPS scheme. However, their construction model is inaccurate, the concrete signature scheme has has three problems： the definition of the strengthened security a security flaw, and the proof of the security is imperfect. With further consideration, a remedial strengthened security model is redefined, and an improved scheme is also proposed, which is existentially unforgeable against adaptively chosen-warrant, chosen-message and chosen-identity attacks in the random oracles. In this condition, the computational Diffie-Hellman （CDH） assumption is used to prove full security for our CLMPS scheme.
In order to achieve secure signcryption schemes in the quantum era, Li Fagen et al. [Concurrency and Computation： Practice and Experience, 2012, 25（4）： 2112-2122] and Wang Fenghe et al. [Applied Mathematics ＆ Information Sciences, 2012, 6（1）： 23-28] have independently extended the concept of signcryption to lattice-based cryptography. However, their schemes are only secure under the random or- acle model. In this paper, we present a lattice-based signcryp- tion scheme which is secure under the standard model. We prove that our scheme achieves indistinguishability against adaptive chosen-ciphertext attacks （IND-CCA2） under the learning with errors （LWE） assumption and existential unforgeability against adaptive chosen-message attacks （EUF- CMA） under the small integer solution （SIS） assumption.
Xiuhua LUQiaoyan WENZhengping JINLicheng WANGChunli YANG
