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With the continuous development of blockchain technology and economy, blockchain applications have been well developed in multiple key areas. The demand for interoperability between different blockchains is also increasing. Cross-chain protocol has become a major approach to solve cross-chain problems by defining a series of cross-chain processes and standards. In response to the problems of long transaction time, high transaction costs, and high degree of centralization in most cross-chain protocols, this paper proposes a three-stage cross-chain protocol based on transaction notary groups and verification notary groups. Without increasing transaction costs and transaction time, the centralization problem of notary mechanism cross-chain technology is solved, realizing secure and fast interaction between different blockchains. Experimental results show that as long as malicious nodes in the notary group do not exceed one-third, the three-stage cross-chain protocol can effectively ensure the security of cross-chain transactions and solve the centralization problem.

Existing blockchains, especially public blockchains, face the challenges of scalability which means the processing capacity will not get better with the addition of nodes, making it somewhat infeasible for mobile computing applications. Some improved technologies are known to speed up processing capacity by shrinking the consensus group, increasing the block capacity and/or shortening the block interval. Even these solutions are met with major problems such as storage limitations and weak security. To face the realistic application scenarios for blockchain technology in the mobile realm, we propose a new public blockchain designed based on sharding, aggregate signature and cryptographic sortition which we call SAC. In SAC, the transaction rate increases with the number of shards while the length of the consensus signature is a constant. Meanwhile, in SAC, the assignment of consensus representatives is controlled by a verifiable random function, which can effectively solve the problem of centralized consensus. In addition, this paper analyzes the performance of SAC to give adequate comparison with other sharding technologies while also giving a rational security analysis. Our experimental results clearly show the potential applicability of this novel blockchain protocol to in mobile computation.

The long-term existence of various vulnerabilities and backdoors in software and hardware makes security threats of the cyberspace more and more serious. Cyberspace mimic defense tries to use uncertain defense to deal with uncertain threat and construct the risk-controlled information system based on components with security flaws. However, mimic defense system is at a preliminary stage of research. It is necessary to pay more attention to the new theory. This paper further expands the ideas from mimic defense system and proposes a typical framework for the system. Then principles of mimic transformation design are explained. This paper also describes concepts of mimic operator and mimic awareness function. Effectiveness of mimic defense system is showed by simulations of mimic defense web server.

In the white paper written on Bitcoin, a chain of blocks was proposed by Satoshi Nakamoto. Since then, blockchain has been rapidly developed. Blockchain is not only limited to the field of cryptocurrency but also has been extensively applied to the Internet of Things (IoT), supply chain finance, electronic evidence storage, data sharing, and e-government fields. Both the public chain and the alliance chain have been extensively developed. In the data processing field, blockchain has a particularly good application potential. The Square Kilometre Array (SKA) is a proposal consisting of a joint venture of more than ten countries, resulting in the world’s largest synthetic aperture radio telescope. In the SKA, the processing scale of the data is large, and it consists of several data processing nodes. The data will be processed in the cloud computing mode. Taking the SKA under consideration, this report proposes a data processing scheme based on blockchain for the anti-counterfeiting, anti-tampering and traceability of data. Furthermore, the authenticity and integrity of the data are assured. The primary aspects include data distribution, data operation and data sharing, which correspond to the data reception, data algorithm processing and result sharing of data operation in the SKA. With this process, the integrity, reliability and authenticity of the data are guaranteed. Additionally, smart contracts, homomorphic hashing, secure containers, aggregate signatures and one-way encrypted channels are implemented to ensure the intelligence, security and high performance of the process.

Blockchain is widely used in encrypted currency, Internet of Things (IoT), supply chain finance, data sharing, and other fields. However, there are security problems in blockchains to varying degrees. As an important component of blockchain, hash function has relatively low computational efficiency. Therefore, this paper proposes a new scheme to optimize the blockchain hashing algorithm based on PRCA (Proactive Reconfigurable Computing Architecture). In order to improve the calculation performance of hashing function, the paper realizes the pipeline hashing algorithm and optimizes the efficiency of communication facilities and network data transmission by combining blockchains with mimic computers. Meanwhile, to ensure the security of data information, this paper chooses lightweight hashing algorithm to do multiple hashing and transforms the hash algorithm structure as well. The experimental results show that the scheme given in the paper not only improves the security of blockchains but also improves the efficiency of data processing.

With the rapid development of cryptocurrency, such as the Bitcoin, block chain technology, as the bottom technology of Bitcoin, has been widely concerned by researchers. Block chain has the characteristics of decentralization, anonymity and non-tampering, which realizes the transformation from social trust to machine trust. As an important part of block chain system, digital signature is relatively inefficient. For this reason, this paper proposes an aggregation signature scheme based on FPGA, which combines the aggregation signature technology with the reconfiguration of FPGA, realizes the aggregation of multiple user signatures into one signature, and has multiple ECC acceleration modules in FPGA. The efficiency of digital signature calculation is improved. Through experimental analysis and comparison, the scheme uses FPGA reconstruction and aggregate signature technology, which not only improves the computational efficiency of ECC, but also improves the efficiency of signature verification and improves the performance of block chain system.

Since its invention, the public blockchain has attracted more attention from both the academia and industry because of its fully decentralization and persistency features. However, the privacy issue in public blockchain is still challengeable. While there exists privacy preservation mechanisms proposed for the public blockchain, almost all of them can only solve partial of the privacy issue, either user privacy or data privacy indeed, in it. In this work, we present a decentralized access control encryption scheme which ensures user and data privacy simultaneously in public blockchain. With our cryptographic solution, the validity of one specific transaction can be publicly verified, while its content can only be retrieved by its intended receivers. Moreover, the origin of this transaction cannot be identified by any participant except the receivers in the network. Our analysis shows that our solution is really suitable to deploy in public blockchain and is proven secure under mathematical assumptions.

The recovery of encrypted information based on password authentication is an important mechanism to maintain network security. As a result, many password recovery systems have been developed. However, those systems are inefficient and energy intensive because they are primarily optimized for CPUs and GPUs. Inspired by a new computing model, namely, mimic computing – a hardware/software co-designed computing model that can dynamically reconfigure appropriate system structures based on application features – we propose a novel password recovery system. The design of such a system is non-trivial and includes several challenges: (1) how to build high-performance password recovery reconfigurable algorithms; (2) how to partition the hardware and software for password recovery; (3) how to optimize resource utilization and power consumption; and (4) how to improve the scalability. We present our insights, design decisions, and implementation details to address these challenges. Our extensive experiments show that the newly designed password recovery system significantly outperforms traditional CPU-based and GPU-based systems in terms of both efficiency and energy consumption. In particular, our system is 27.81 and 4.23 times faster than CPU-based and GPU-based systems in terms of password cracking, and our system consumes 14.97 and 5.97 times less energy than CPU-based and GPU-based systems.

With the rapid development of the Internet, increasingly more attention has been paid to network security problems. A network security defense technology has become a very important research field. Currently, most network equipment transmits data in plaintext at the data link layer, which exposes important information, such as IP addresses, port numbers, and application protocols, to an attacker and provides an opportunity for network attacks. To protect a network against attacks and ensure its security, this paper proposes a mimic encryption system for network security. Based on the concepts of moving target defense and mimic security defense, using the principles of randomization, dynamism, and diversification, a data link layer mimic encryption system is constructed from the underlying network of an information system. By transforming the frame format, a reconfigurable encryption algorithm, an hash algorithm, and a pseudo-random number generator are used to design different combination encryption modes. Then, the hash value of an encrypted frame is obtained by performing the hash operation, and feedback update is performed to generate new key parameters for the hash key pool. In addition, the pseudo-random selection of combinations of encryption algorithms and keys is performed to achieve “one frame-one key”. Finally, an FPGA is used as the network encryption card, and a CPU is used to realize two-party key agreement and the upper layer application. Using the FPGA + CPU hardware and software collaboration, the attack surface is expanded. Taking advantage of the high anti-interference property of an FPGA, part of the attack against the software system is filtered. The experimental results and analysis show that the encryption and decryption performance of this system in a 10 G network are approximately 500 MB/s. Thus, the system can effectively prevent the leakage of user data and resist network sniffing, vulnerability attacks, exhaustive key search attacks, and ciphertext-only attacks. Moreover, this system provides high security.

Performance analysis of master-slave based reconfigurable architecture and standalone SOPC based reconfigurable architecture using an analytical model.A massive-sessions optimized TCP/IP offload engine that supports up to 100K TCP sessions under 10Gbps line rate.An online dynamic scheduling method that can reconfigure or power off FPGA nodes according to workload variance to reduce the runtime energy consumption.Prototype of a reconfigurable cluster system based on standalone SOPC to provide cloud services, achieving up to 38X speed up in performance and 418X improvement in energy efficiency compared to the software based cloud systems. Traditional cloud service providers build large data-centers with a huge number of connected commodity computers to meet the ever-growing demand on performance. However, the growth potential of these data-centers is limited by their corresponding energy consumption and thermal issues. Energy efficiency becomes a key issue of building large-scale cloud computing centers. To solve this issue, we propose a standalone SOPC (System on a Programmable Chip) based platform for cloud applications. We improve the energy efficiency for cloud computing platforms with two techniques. First, we propose a massive-sessions optimized TCP/IP hardware stack using a macro-pipeline architecture. It enables the hardware acceleration of pipelining execution of network packet offloading and application level data processing. This achieves higher energy efficiency while maintaining peak performance. Second, we propose a online dynamic scheduling strategy. It can reconfigure or shut down FPGA nodes according to workload variance to reduce the runtime energy consumption in a standalone SOPC based reconfigurable cluster system. Two case studies including a webserver application and a cloud based ECG (electrocardiogram) classification application are developed to validate the effectiveness of the proposed platform. Evaluation results show that our SOPC based cloud computing platform can achieve up to 418X improvement in terms of energy efficiency over commercial cloud systems.

Identity authentication is the first line of defense to ensure the security of information systems, and passwords are the most widely used authentication method. Choosing a valid password structure is an effective way to prevent password attacks, such as password dictionary attack. This article talked 68386069 real plaintext passwords with statistical their various features, summarized several rules for generating highly utilized passwords in certain styles. Based on these statistical features and rules, it generated high-probability password structure gene banks. With them, it formulates a dictionary to generate the candidate passwords. Thereby, this can enhance the efficiency of password recovery. We conducted extensive experiments by the real password test data, and the experimental results, compared with the dictionary provided by major websites, show that the dictionary of high probability password structure hit rate increased by about 30%. At the same time, this dictionary can save about one-third of the running time.

Bitcoin is the first decentralized cryptocurrency proposed by Satoshi Nakamoto. Although transactions are conducted between pseudonyms, Bitcoin cannot offer strong privacy guarantees. Mixing coins, to some extent, can address this drawback through different technologies, but also meets flexibility, storage and anonymity problems. This paper proposes a decentralized coin mixing scheme CoinMingle, based on ring signature, one-time output address, CoinJoin and our mutual recognition delegation strategy. Our mutual recognition delegation strategy is simple but effective: when a user prepares to submit messages, he will delegate it to other users for anonymity. Users in CoinMingle don’t need pre-compute. And CoinMingle can tolerate different input amounts and plug the leak of personal information in shuffling phase. In addition, CoinMingle owns parallel structure which is more efficient than other coin mixing schemes.

With the rise of Bitcoin, blockchain which is the core technology of Bitcoin has received increasing attention. Privacy preserving and performance on blockchain are two research points in academia and business, but there are still some unresolved issues in both respects. An aggregate signature scheme is a digital signature that supports making signatures on many different messages generated by many different users. Using aggregate signature, the size of the signature could be shortened by compressing multiple signatures into a single signature. In this paper, a new signature scheme for transactions on blockchain based on the aggregate signature was proposed. It was worth noting that elliptic curve discrete logarithm problem and bilinear maps played major roles in our signature scheme. And the security properties of our signature scheme were proved. In our signature scheme, the amount will be hidden especially in the transactions which contain multiple inputs and outputs. Additionally, the size of the signature on transaction is constant regardless of the number of inputs and outputs that the transaction contains, which can improve the performance of signature. Finally, we gave an application scenario for our signature scheme which aims to achieve the transactions of big data on blockchain.

This paper studies the decentralized routing control of data communication networks. Taking the physical constraints on the data flow and the network-induced delays into consideration, the decentralized routing control problem is reformulated as a constrained control problem, and the restriction of initial message lengths is no longer needed. By defining a general Lyapunov functional and applying a reciprocally convex combination technique to deal with the network-induced delays, less conservative and less complex designing conditions are obtained in terms of linear matrix inequalities (LMIs). A simulation example is also given to illustrate the effectiveness of the proposed designing scheme.