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Commutative encryption and watermarking ( CEW) is a combination of cryptographic and digital watermarking technology, which is used for multimedia information security and copyright protection. In order to ensure the security of carrier data, this paper proposed an exchange encryption watermarking algorithm based on ZUC. The algorithm used the ZUC sequence cipher to generate the key and used modular operation to encrypt the carrier information. The sequence of watermark embedding operation and data encryption operation did not affect the generation of watermark ciphertext data. When extracting the watermark, the algorithm could realize the exchange of password operation and watermark operation. The experimental results show that the watermark extraction in ciphertext domain is consistent with that in plaintext domain, the image containing watermark is of high quality, the efficiency of encryption and decryption, watermark embedding and extraction are higher, and the algorithm has a certain robustness. [ABSTRACT FROM AUTHOR]

The design of efficient and secure lattice-based post quantum key exchange protocols has certain practical and theoretical significance. This paper proposed a scheme used straight-forward transformation LWE encryption mechanism and a ciphertext compression technology. This was a passively secure and practical key exchange protocol. Frodo was a key exchange scheme based on LWE problem proposed by Bos et al. which used the error reconciliation mechanism proposed by Peikert. The main advantage of the scheme over Frodo was simplicity. Compared with Frodo. the communications traffic merely increased by only 1.09%. reduced the complexity of the scheme effectively. It proved scheme to be passive security. which could resist quantum computer attacks. Compared with existing key exchange protocol based on learning with error, this protocol is very competitive. [ABSTRACT FROM AUTHOR]

In order lo improve the management efficiency of digital certificate of trusted third party; certificate authority ( CA) , this paper presented a multi-certificate public key infrastructure which was based on the NTRUSign signature scheme. This scheme hashed some coefficients of public key of NTRUSign,and completed the remaining coefficients of it lo get a new public key. Then this scheme circulated the operation above and formed a certificate chain, which could apply lo the MCPKI scenario. This scheme provided a new idea for the management of digital signature for CA. Users only need lo apply lo the CA once, then could have all the certificates on the certificate chain. Compared with traditional PKI,MCPKI achieved a more efficient management of certificate for CA. The scheme of MCPKI not only replaces the certificates spontaneously, but also realizes the self-signed and self-revoked of the certificate. [ABSTRACT FROM AUTHOR]

NTRU is the most practical cryptosystem based on the lattice structure currently. However, comparing with the encryption and signature schemes based on the NTRU, there was very few papers in concern of the key agreement protocol. To address these problems, this paper proposed a new authenticated key agreement protocol, which was based on the NTRU lattice. Under the random oracle model, the proposed scheme is provably secure in the eCK model, also can resist man-in-the-middle attack, replay attack, impersonation attack and achieves weak perfect forward secrecy. Compared with the traditional DH and ECDH scheme, the scheme not only has higher computational efficiency, but also resists quantum attacks because of the shortest vector problem on lattice. [ABSTRACT FROM AUTHOR]

Van Dijk et al. described a fully homomorphic encryption scheme over the integers at Eurocrypt 2010. The main appeal of this scheme is its conceptual simplicity. The original scheme which based on ideal lattices is replaced by a very simple homomorphic encryption scheme described by the integers. This simplicity comes at the expense of a publickey size in ~O (λ10) and only encrypts 1 bit at a time. On the basis of the original DGHV homomorphism encryption scheme,this paper proposed a scheme by changing intenger selection mode and modulus. It could encrypt h bits at a time, and reduced the public key size to ~O (λ7). Then, it gave the security certificates and efficiency analysis. The scheme is based on the same difficult problems as DGHV, and has a better performance in efficience. [ABSTRACT FROM AUTHOR]

There were some advantages in the ideal lattices which can decrease the keys, shorten the length of key and reduce the cost without reducing the safety. By combining the merits of ideal lattices with the oblivious transfer protocol on general lattices and expanding the general lattices’ trapdoors generation algorithm presented by Peiker on the EURO CRYPT 2012 to the ideal lattices, this paper presented an ideal lattice-based 1 -out-of-n oblivious transfer protocol. Using the trapdoor one-way function based learning with errors on ideal lattice ensures the privacy of submitter and receiver, in addition proved the completeness and security. In terms of efficiency, since using merely modular addition and modular multiplication operations, the protocol was efficient. Besides, it restricted the size of key the length of plaintext and ciphertext effectively and reduced the communication cost significantly. [ABSTRACT FROM AUTHOR]

In order to construct an efficient type-based proxy re-encryption scheme that can resist the quantum attack, this paper cryptanalyzed Zhang' s IBPRE scheme based on lattice, and shown that the scheme was vulnerable to collusion attack so that the private key was leaked. It presented the first dynamic type-based proxy re-encryption scheme based on lattice hard problem, whose security proved reduced to LWE assumption tightly. The construction was IND-CPA-secure cryptosystem. The scheme not only had the functions of the traditional type-based proxy re-encryption scheme, but also could resist the quantum attack, and the delegator of the ciphertext could modify the type of ciphertext dynamically. The proposed scheme is more useful in practical applications. [ABSTRACT FROM AUTHOR]

Aiming at the differential power attack of the encryption scheme based on lattice, Reparaz proposed an additively homomorphic R-LWE masking scheme in PQC 2016. This scheme could against the differential power attack effectively, but the additively homomorphic algorithm between the ciphertexts made the size of noise increase. It declined the rate of decryption correctness. In view of this problem, this paper proposed an improved R-LWE homomorphic masking scheme. By introducing the modular switching technology, it made a modular reduction with the cipher text of additively homomorphic. Under the premising that plaintext and the ciphertext were corresponding, it declined the size of noise in the ciphertext. And it could improve the decryption correctness of the scheme. In order to protect the sub keys, it introduced a random matrix to mask the sub key. And it made the correctness analysis and the safety proof. The proposed scheme has better security and efficiency compared to the original scheme. [ABSTRACT FROM AUTHOR]

In order to protect users’ privacy better and make signatures resistant to quantum attack, a secure and efficient blind signature scheme on ideal lattice was proposed using the rejection sampling theorem and the relationship between high and low order bits. This blind signature function can be achieved through simple calculations without trapdoor functions. the security of the scheme is based on Short Integer Solution(ISISn,m,q,η(s)) assumption, and this scheme has the characteristics of blindness and one-more(OM) unforgeability. Besides, the public and private keys are short and the signature length is only llodq. In general, the scheme is efficient and safe. [ABSTRACT FROM AUTHOR]

Aiming at the problems of possible information loss and low security in the process of image encryption, this paper proposed a color image lossless authentication algorithm based on AEGIS. The algorithm used the file header of the image to get the initial state, encrypted the image by updating the internal state of AEGIS, then hided the authentication label generated by the status update into the encrypted image, extracted the label from the encrypted image during decryption and restored the image by AEGIS. It achieved the authentication function and guaranteed the authenticity and integrity of the image. Comparing with other image encryption algorithms, this algorithm had higher computational efficiency and lower amount of information contained in ciphertext images. The experimental results show that the algorithm can achieve fast lossless authentication encryption and decryption for color images. [ABSTRACT FROM AUTHOR]

Privacy information security retrieval of multi-party data sources is an urgent problem in network security. The feature of oblivious transfer technology is to ensure the data security of each participant. Therefore, this paper combined oblivious transfer technology with homomorphic encryption and symmetric encryption in cryptography to design an anonymous query protocol for multi-party data sources. Firstly, based on the idea of oblivious transfer, this paper designed a three-party anonymous query protocol, and gave the model of the protocol and the specific process of the protocol. Secondly, this paper proved and analyzed the correctness and security of the protocol. Finally, it extended the three-party anonymous query protocol to the multiparty query protocol, and it applied to the verification of blacklist users in digital product transaction, which solved the problem of malicious transaction of buyer users in the process of network security transaction. Experimental data shows that the algorithm has correct query results and high efficiency under the condition of ensuring the data security of all parties. [ABSTRACT FROM AUTHOR]

In order to effectively solve the problems of multimedia data security and copyright protection in the process of transmission and storage, this paper proposed a commutative encryption and watermarking algorithm based on Zu Chongzhi(ZUC) stream cipher algorithm and DWT-SVD. Based on the invariance of the singular value, the algorithm embedded the watermark into the singular value, and used the ZUC algorithm to permutate and encrypt the set of the singular value matrix and the set of the singular matrix respectively. The sequence of embedding operation and encryption operation did not affect the generation of the watermarked ciphertext, meanwhile, both watermarked ciphertext and decrypted plaintext can extract watermark completely. The experimental results show that the watermark has good invisibility, and the algorithm has high security and a certain robustness. [ABSTRACT FROM AUTHOR]

After analyzing the way to attack RSA system and NTRU system based on the lattice reduction, this paper presented a method how to generate the lattice in the lattice reduction. The method was mainly used in the cry ptosystems which had the vectors, polynomials or find the small solutions to the equation of the higher degree. In the end, the method was realized in the Regev’s cryptosystem which was based on the LWE,and gave the way how to generate the lattice in this cryptosystem. This application proves the useful of this method. [ABSTRACT FROM AUTHOR]

Since the number of data items keys is larger, much higher security is needed in database encryption systems. In view of this question, we propose new key management schemes based on access control and Chinese remainder theorem which makes the management of data items keys convenient. A large number of the data items keys Ki which the user ui has access to, can be compounded to user class keys uki when the user applies for the key, then this key is saved. When the user decrypts the data, user class keys uki are broken down into key data items using the system tables and the Chinese remainder theorem. The schemes can solve the problems of high time cost on processing data and more system resources occupation, thus improving the efficiency and security of the key management in the cipher text database. Experiments and comparison prove the significant improvement in efficiency and security of key management. [ABSTRACT FROM AUTHOR]