844,303 research outputs found
Integrity protection for code-on-demand mobile agents in e-commerce
The mobile agent paradigm has been proposed as a promising solution to facilitate distributed computing over open and heterogeneous networks. Mobility, autonomy, and intelligence are identified as key features of mobile agent systems and enabling characteristics for the next-generation smart electronic commerce on the Internet. However, security-related issues, especially integrity protection in mobile agent technology, still hinder the widespread use of software agents: from the agent’s perspective, mobile agent integrity should be protected against attacks from malicious hosts and other agents. In this paper, we present Code-on-Demand(CoD) mobile agents and a corresponding agent integrity protection scheme. Compared to the traditional assumption that mobile agents consist of invariant code parts, we propose the use of dynamically upgradeable agent code, in which new agent function modules can be added and redundant ones can be deleted at runtime. This approach will reduce the weight of agent programs, equip mobile agents with more flexibility, enhance code privacy and help the recoverability of agents after attack. In order to meet the security challenges for agent integrity protection, we propose agent code change authorization protocols and a double integrity verification scheme. Finally, we discuss the Java implementation of CoD mobile agents and integrity protection
CODEWEAVE: exploring fine-grained mobility of code
This paper is concerned with an abstract exploration of code mobility constructs designed for use in settings where the level of granularity associated with the mobile units exhibits significant variability. Units of mobility that are both finer and coarser grained than the unit of execution are examined. To accomplish this, we take the extreme view that every line of code and every variable declaration are potentially mobile, i.e., it may be duplicated or moved from one program context to another on the same host or across the network. We also assume that complex code assemblies may move with equal ease. The result is CODEWEAVE, a model that shows how to develop new forms of code mobility, assign them precise meaning, and facilitate formal verification of programs employing them. The design of CODEWEAVE relies greatly on Mobile UNITY, a notation and proof logic for mobile computing. Mobile UNITY offers a computational milieu for examining a wide range of constructs and semantic alternatives in a clean abstract setting, i.e., unconstrained by compilation and performance considerations traditionally associated with programming language design. Ultimately, the notation offered by CODEWEAVE is given exact semantic definition by means of a direct mapping to the underlying Mobile UNITY model. The abstract and formal treatment of code mobility offered by CODEWEAVE establishes a technical foundation for examining competing proposals and for subsequent integration of some of the mobility constructs both at the language level and within middleware for mobility
QR code awareness in Stockholm, Sweden
This tech report describes the findings of a street survey on
awareness of QR codes (2D barcodes) of the general public in
Stockholm, Sweden. 108 passers-by were surveyed. Of these
participants, a large majority (77%) did not recognize a QR code, and
8% reported seeing such a code before, but did not know it could be
scanned using a mobile phone app. Only 15% knew what the shown QR code
was, and that it could be read using a QR code reader on a mobile
phone. The awareness of QR codes by the general public could be
considered rather low, and their utility in Swedish public settings is
currently debatable
Distributed MIMO coding scheme with low decoding complexity for future mobile TV broadcasting
A novel distributed space-time block code (STBC) for the next generation
mobile TV broadcasting is proposed. The new code provides efficient performance
within a wide range of power imbalance showing strong adaptivity to the single
frequency network (SFN) broadcasting deployments. The new code outperforms
existing STBCs with equivalent decoding complexity and approaches those with
much higher complexities
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