Public key based bidirectional shadow image authentication without pixel expansion in image secret sharing

Image secret sharing(ISS)is gaining popularity due to the importance of digital images and its wide application to cloud-based distributed storage and multiparty secure computing.Shadow image authentication generally includes shadow image detection and identification,and plays an important role in ISS.However,traditional dealer-participatory methods,which suffer from significant pixel expansion or storing auxiliary information,authenticate the shadow image mainly during the decoding phase,also known as unidirectional authentication.The authentication of the shadow image in the distributing(encoding)phase is also important for the participant.In this study,we introduce a public key based bidirectional shadow image authentication method in ISS without pixel expansion for a(k,n)threshold.When the dealer distributes each shadow image to a corresponding participant,the participant can authenticate the received shadow image with his/her private key.In the decoding phase,the dealer can authenticate each received shadow image with a secret key;in addition,the dealer can losslessly decode the secret image with any k or more shadow images.The proposed method is validated using theoretical analyses,illustrations,and comparisons.

NTRU_SSS:Anew Method Signcryption Post Quantum Cryptography Based on Shamir’s Secret Sharing

With the advent of quantum computing,numerous efforts have been made to standardize post-quantum cryptosystems with the intention of(eventually)replacing Elliptic Curve Cryptography(ECC)and Rivets-Shamir-Adelman(RSA).A modified version of the traditional N-Th Degree Truncated Polynomial Ring(NTRU)cryptosystem called NTRU Prime has been developed to reduce the attack surface.In this paper,the Signcryption scheme was proposed,and it is most efficient than others since it reduces the complexity and runs the time of the code execution,and at the same time,provides a better security degree since it ensures the integrity of the sent message,confidentiality of the data,forward secrecy when using refreshed parameters for each session.Unforgeability to prevent the man-in-the-middle attack from being active or passive,and non-repudiation when the sender can’t deny the recently sent message.This study aims to create a novel NTRU cryptography algorithm system that takes advantage of the security features of curve fitting operations and the valuable characteristics of chaotic systems.The proposed algorithm combines the(NTRU Prime)and Shamir’s Secret Sharing(SSS)features to improve the security of the NTRU encryption and key generation stages that rely on robust polynomial generation.Based on experimental results and a comparison of the time required for crucial exchange between NTRU-SSS and the original NTRU,this study shows a rise in complexity with a decrease in execution time in the case when compared to the original NTRU.It’s encouraging to see signs that the suggested changes to the NTRU work to increase accuracy and efficiency.

A DRM System Based on Mobile Agent for Digital Rights Redistribution

We propose a digital rights management （DRM） system based on mobile agent to protect the copyrights of content providers. In the system, the content provider creates a time limited blackbox out of an original agent and dispatches it to the user end to enforce DRM functions. The blackbox is an agent that can resist the attacks from the malicious user in a certain time interval. Owing to digital rights redistribution support, the user whose rights belong to redistribution category can transfer his rights to other users. Moreover, by introducing public key infrastructure （PKI） and certificate authority （CA） role, the security of the session can be ensured. An analysis of system security and performance and a comparison with traditional DRM system is given.

A Novel Scheme for Deleting Group Members

Deleting group members safely and efficiently has been a hot research issue in the field of the group signature. Some resolutions have been proposed by cryptography experts, but in some way, problems like loophole and low efficiency have been confusing us in the research. To solve the problem, the writers try to give a new secret key updating algorithm based on improving Wang Shangping’s group members deleting scheme, and analyze the safety and efficiency of implemen- tation systematically in the paper.

Cryptographic Protocols Based on Nielsen Transformations

We introduce in this paper cryptographic protocols which use combinatorial group theory. Based on a combinatorial distribution of shares we present secret sharing schemes and cryptosystems using Nielsen transformations. Nielsen transformations are a linear technique to study free groups and general infinite groups. In addition the group of all automorphisms of a free group F, denoted by AUT (F), is generated by a regular Nielsen transformation between two basis of F, and each regular Nielsen transformation between two basis of F defines an automorphism of F.

A Solution of Secure Communication in the Current and Future Mobile Network

To secure wireless communication, this paper provides a solution based on theabilities of the current mobile terminals. This paper also proposes a mechanism that can secure thecommunication between the current mobile terminals and the Internet Web Server. Yield to thecapabilities of the current mobile terminals, the public key techniques cannot be used now. But inthe future, the memory space and the computation ability of the mobile terminals will no longer beany puzzles, so certificate and Public Key Infrastructure (PKI) can be used to make wirelesscommunication security. This paper also proposes PKI architecture in the future mobile network.Finally this paper makes an assumption of the network's development and its secure issues.

Security of account and privacy of transaction for bitcoin

As a kind of cryptocurrency, bitcoin has attracted much attention with its decentralization. However, there is two problems in the bitcoin transactions ： the account security and transaction privacy. In view of the above problems, a new partially blind threshold signature scheme is proposed, which can both enhance the security of bitcoin account and preserve the privacy of transaction. Firstly, transaction amounts are encrypted by employing the homomorphic Paillier cryptosystem, and output address is disturbed by using one-time public key. Then the encrypted or disrupted transaction information is signed by multiple participants who are authorized by using threshold secret sharing. Compared with partially blind fuzzy signature scheme, the proposed scheme can fully preserve the transaction privacy. Furthermore, performance analysis shows that the proposed scheme is secure and effective in practical applications.