公平的消息传输协议

公平性是电子交易走向实际应用所必须解决的课题.提出了一个在电子商务环境下消息传输协议,目的是为了保证在消息传输协议终止后,双方都能收到对方消息或都收不到.该协议基于乐观模型,使用了可转化签名和非交互式零知识证明等技术.协议在实现有效性、公平性和不可抵赖性要求的基础上,还实现了透明的可信第3方,且生成的最终抗抵赖证据是标准的GDH签名（gap diffie-hellman signature）,这使得该协议既高效,又非常容易融入现有交易系统.     

Time-averaging of high-speed data transfer protocols

We propose two modeling approaches of additive-increase/multiplicative-decrease (AIMD) congestion control mechanisms. The first separates the increase and decrease parts whereas the second describes the rate evolution of the congestion window as a continuous process governed by a differential equation. We relate these approaches and show that the second (fluid-flow) model results from deterministic time averaging of the first (discontinuous) model. A generalized class of nonlinear protocols, which includes Floyd's HighSpeed TCP, is then proposed and analyzed. Our findings are validated by simulation.     

Scalable RFID security protocols supporting tag ownership transfer

We identify privacy, security and performance requirements for radio frequency identification (RFID) protocols, as well as additional functional requirements such as tag ownership transfer. Many previously proposed protocols suffer from scalability issues because they require a linear search to identify or authenticate a tag. In support of scalability, some RFID protocols, however, only require constant time for tag identification, but, unfortunately, all previously proposed schemes of this type have serious shortcomings. We propose a novel scalable RFID authentication protocol based on the scheme presented in Song and Mitchell (2009) [1], that takes constant time to authenticate a tag. We also propose secret update protocols for tag ownership and authorisation transfer. The proposed protocols possess the identified privacy, security and performance properties and meet the requirements for secure ownership transfer identified here.     

Vulnerability analysis of RFID protocols for tag ownership transfer

In RFIDSec’08, Song proposed an ownership transfer scheme, which consists of an ownership transfer protocol and a secret update protocol [7]. The ownership transfer protocol is completely based on a mutual authentication protocol proposed in WiSec’08 [8]. In Rizomiliotis et al. (2009) [6], van Deursen and Radomirovic (2008), the first weaknesses to be identified (tag and server impersonation) were addressed and this paper completes the consideration of them all. We find that the mutual authentication protocol, and therefore the ownership transfer protocol, possesses certain weaknesses related to most of the security properties initially required in protocol design: tag information leakage, tag location tracking, and forward traceability. Moreover, the secret update protocol is not immune to de-synchronization attacks.     

The synthesis of communication protocols

We define a notation (specification language) for describing desired patterns of communication among components of a distributed system through multiport, unreliable channels. Our language specifies the network topology, and the kinds of information transmission desired. We give a polynomial-time algorithm for determining whether a specification is satisfiable; our algorithm can actually construct a protocol that achieves the specified exchange of information, optimized with respect to two possible criteria. Examples suggest that our method can automatically synthesize reasonably complex protocols.Research supported by the National Science Foundation. Presently at the University of California at San Diego.     

The synthesis of communication protocols

We define a notation (specification language) for describing desired patterns of communication among components of a distributed system through multiport, unreliable channels. Our language specifies the network topology, and the kinds of information transmission desired. We give a polynomial-time algorithm for determining whether a specification is satisfiable; our algorithm can actually construct a protocol that achieves the specified exchange of information, optimized with respect to two possible criteria. Examples suggest that our method can automatically synthesize reasonably complex protocols.     

A generic construction to build simple oblivious transfer protocols from homomorphic encryption schemes

The Journal of Supercomputing - Oblivious transfer is a fundamental problem in cryptography where it is required that a sender transfers one of potentially many pieces of information to a receiver...     

The computational power of population protocols

We consider the model of population protocols introduced by Angluin et al. (Computation in networks of passively mobile finite-state sensors, pp. 290–299. ACM, New York, 2004), in which anonymous finite-state agents stably compute a predicate of the multiset of their inputs via two-way interactions in the family of all-pairs communication networks. We prove that all predicates stably computable in this model (and certain generalizations of it) are semilinear, answering a central open question about the power of the model. Removing the assumption of two-way interaction, we also consider several variants of the model in which agents communicate by anonymous message-passing where the recipient of each message is chosen by an adversary and the sender is not identified to the recipient. These one-way models are distinguished by whether messages are delivered immediately or after a delay, whether a sender can record that it has sent a message, and whether a recipient can queue incoming messages, refusing to accept new messages until it has had a chance to send out messages of its own. We characterize the classes of predicates stably computable in each of these one-way models using natural subclasses of the semilinear predicates. James Aspnes was supported in part by NSF grants CNS-0305258 and CNS-0435201. David Eisenstat was supported in part by a National Defense Science and Engineering Graduate Fellowship and by a Gordon Y. S. Wu Graduate Fellowship. Eric Ruppert was supported in part by the Natural Sciences and Engineering Research Council of Canada.     

The construction of self-synchronizing finite state protocols

A technique is presented for constructing a finite state protocol from an originally given finite state specification of one process. We present three constructions, showing that they each provide send-receive symmetric solutions which are selfsynchronizing. Two lemmas are proved that provide insight into the types of interactions that arise in these types of finite state protocols. In essence we show that interactions occur between the processes only through isomorphic transitions and that during any interaction between the processes at most one of the two FIFO queues of messages is nonempty.Raymond E. Miller has been Director and Professor of the School of Information and Computer Science at the Georgia Institute of Technology since 1980. Prior to that he was employed by IBM for over thirty years, most of this time as a Research Staff Member at the IBM Research Center in Yorktown Heights, N.Y., where he held a number of technical management positions. He received a B.S. in Mechanical Engineering from the University of Wisconsin, Madison, and a B.S. in Electrical Engineering, M.S. in Mathematics, and PhD in Electrical Engineering, all from the University of Illinois, Urbana. His research areas of interest include theory of computation, machine organization, parallel computation, and communication protocols. He has written over sixty papers, authored a two volume book on switching theory, served as editor for a book on computer complexity, and is editor of a book series of foundations of computer science. He is a Fellow of the IEEE, a member of ACM and AAAS and has been active in numerous ACM capacities including being a member of the ACM Council for six years, an ACM National Lecturer for 1982–83, and a member of the AFIPS Board of Directors for four years. He is a member of the Computer Science Board, and was a member of the NSF Advisory Committee for Computer Research from 1982 to 1985, serving as Chairman for 1983–84. He has taught in a visiting or part time capacity at numerous institutions including Cal Tech, New York University, Yale, University of California at Berkeley and the Polytechnic Institute of New York.This work was partially supported through a contract with GTE Laboratories     

The group paradigm for concurrency control protocols

The authors propose a paradigm for developing, describing, and proving the correctness of concurrency control protocols for replicated databases in the presence of failures or communication restrictions. The approach used is to hierarchically divide the problem of achieving one-copy serializability by introducing the notion of a `group' that is a higher level of abstraction than transactions. Instead of dealing with the overall problem, the paradigm breaks it into two simpler ones: (1) a local policy for each group that ensures a total order of all transactions in that group; and (2) a global policy that ensures a correct serialization of all groups. The paradigm is used to demonstrate the similarities between several concurrency control protocols by comparing the way they achieve correctness     

The cost of recovery in message logging protocols

Past research in message logging has focused on studying the relative overhead imposed by pessimistic, optimistic and causal protocols during failure-free executions. In this paper, we give the first experimental evaluation of the performance of these protocols during recovery. Our results suggest that applications face a complex tradeoff when choosing a message logging protocol for fault tolerance. On the one hand, optimistic protocols can provide fast failure-free execution and good performance during recovery, but are complex to implement and can create orphan processes. On the other hand, orphan-free protocols either risk being slow during recovery (e.g. sender-based pessimistic and causal protocols) or incur a substantial overhead during failure-free execution (e.g. receiver-based pessimistic protocols). To address this tradeoff, we propose hybrid logging protocols, which are a new class of orphan-free protocols. We show that hybrid protocols perform within 2% of causal logging during failure-free execution and within 2% of receiver-based logging during recovery     

The imposition of protocols over open distributed systems

In order to facilitate enforcement of protocols, an architecture for distributed systems is introduced under which all interactions between objects are governed by an explicit and strictly enforced set of rules, called the law of the system. This law is global in the sense that all the objects of the system are made to obey it, but the maintenance of the law and its enforcement are performed locally, at each object (or node). The term law is used to emphasized that it not only provides the specification of protocols, but actually governs the system by enforcing them. In other words, under this architecture a protocol can be established simply by writing it into the law of a system, without having to worry about the programs that drive the various objects that might populate that system. The law, then, is the enforced specification of protocols. It is shown that various familiar protocols can be established under this architecture. A technique for online distributed updating of the global law of a system is presented     

基于嵌入式TCP/IP的实时数据传输

本文介绍一种实用的基于嵌入式TCP/IP技术的实时数据传输系统,分析了其硬件和软件系统。结合系统控制对象的分散性和网络化管理的特点,重点论述嵌入式操作系统、嵌入式TCP/IP技术、系统可靠性、安全性等关键技术。