物联网中移动节点抗克隆攻击的UC安全认证协议

物联网中的感知网一般由计算、通信和存储能力极差的感知节点通过移动节点和静态节点相结合的方式构成,以采集信息;而传输网通常利用现有互联网的基础设施,提供强大的计算、通信和存储服务。为了满足物联网中移动节点漫游时实施接入认证的访问控制要求,同时兼顾实际应用中可行性与移动节点轻量级、抗物理克隆攻击等的安全性需求,基于物理不可克隆函数(Physical Unclonable Function,PUF),提出了移动节点抗克隆攻击的UC(Universally Composable)安全认证协议,其可实现移动节点漫游到其他区域时与接入基站之间的双向认证与密钥交换过程。分析表明,所提出的协议在UC安全模型下是可证明安全的。     

可调可重构的环形振荡器物理不可克隆函数

针对环形振荡器物理不可克隆函数均匀性与独特性不够理想的问题,提出一种可调可重构的环形振荡器物理不可克隆函数设计.该设计包含可重构环形振荡器模块、整合器模块和裁决器模块.可重构环形振荡器模块由多个独立且具有相同设计的可重构环形振荡器-计数器组构成,芯片各部分的工艺偏差由计数器的数值反映;整合器模块通过将多个计数器数值进行...     

轻量级可配置强物理不可克隆函数设计

为了解决物理不可克隆函数(PUF)结构简单、容易遭受建模攻击等问题,提出一种基于动态线性反馈移位寄存器(LFSR)的强PUF抗攻击混淆设计.首先使用一个固定结构的LFSR作为伪随机数发生器,为混淆逻辑提供随机选择信号;然后使用一个内置多个反馈多项式的动态LFSR作为混淆逻辑,对输入激励进行混淆;最后将混淆后的激励输入内嵌PUF电路,使攻击者无法获取内嵌PUF的真实激励,从而提高PUF的抗建模攻击能力.用Python和FPGA进行了仿真和数据收集,在收集到数据集上的实验表明,所提设计具有接近理想值的均匀性(49.8％)和唯一性(49.9％),保持了与经典强PUF相同的可靠性.该设计结构简单,硬件开销较低,能够抵抗多种主流机器学习和深度学习算法的建模攻击.     

基于物理不可克隆函数的RFID双向认证

在物联网应用中,基于传统加密手段的无线射频识别(RFID)认证协议计算量较大,在资源有限的设备中不具有可操作性.为解决该问题,提出一种基于物理不可克隆函数的RFID双向认证协议.分析RFID系统协议的安全需求,根据物理不可克隆函数设计轻量级的双向安全认证协议,利用形式化分析语言证明协议的安全性.分析结果表明,与随机化Hash-Lock、轻量级认证协议等相比,该协议不仅能够有效防止假冒、重放、追踪攻击,也能抵抗物理克隆攻击.     

对建模误差具有鲁棒性的MRAC方案

研究了模型参考自适应控制系统存在未建模动态的鲁棒性问题。基于Popov超稳定理论,采用从模型取状态技术,并将系统的建模误差转化为已知干扰,设计出一种对建模误差具有鲁棒性的MRAC方案。     

Rational Error Correction

Under general conditions, linear decision rules of agents with rational expectations are equivalent to restricted error corrections. However, empirical rejections of rational expectation restrictions are the rule, rather than the exception, in macroeconomics. Rejections often are conditioned on the assumption that agents aim to smooth only the levels of actions or are subject to geometric random delays. Generalizations of dynamic frictions on agent activities are suggested that yield closed-form, higher-order decision rules with improved statistical fits and infrequent rejections of rational expectations restrictions. Properties of these generalized `rational' error corrections are illustrated for producer pricing in manufacturing industries.     

安全芯片错误诱导攻击防护方案

针对安全芯片容易遭受错误诱导攻击的情况,提出一种安全芯片错误诱导攻击防护方案。在分析诱导错误产生原因的基础上,设计存储区安全管理逻辑、硬件篡改防护机制和内外数据交互协议,从而增强芯片对错误诱导攻击的防御能力,提高芯片自身的安全性与运行的稳定性。     

Communication Protocols for Secure Distributed Computation of Binary Functions

A common task in parallel processing is the distributed computation of a function by a number of processors, each of which possesses partial information relevant to the value of that function. In this paper we develop communication protocols which allow for such computation to take place while maintaining the value of the function secret to an eavesdropper. Of interest is the communication complexity of such protocols. We begin by considering two processors and two channels, one secret and one public, and present a protocol which minimizes the number of bits exchanged over the secret channel, while maintaining -uncertainty about the value of the function for the eavesdropper. We show that all binary functions can be kept -secret using a constant number of bits independent of the size of their domain. We then generalize our results to N processors communicating over a network of arbitrary topology.     

Dual Illumination Estimation for Robust Exposure Correction

Exposure correction is one of the fundamental tasks in image processing and computational photography. While various methods have been proposed, they either fail to produce visually pleasing results, or only work well for limited types of image (e.g., underexposed images). In this paper, we present a novel automatic exposure correction method, which is able to robustly produce high‐quality results for images of various exposure conditions (e.g., underexposed, overexposed, and partially under‐ and over‐exposed). At the core of our approach is the proposed dual illumination estimation, where we separately cast the under‐and over‐exposure correction as trivial illumination estimation of the input image and the inverted input image. By performing dual illumination estimation, we obtain two intermediate exposure correction results for the input image, with one fixes the underexposed regions and the other one restores the overexposed regions. A multi‐exposure image fusion technique is then employed to adaptively blend the visually best exposed parts in the two intermediate exposure correction images and the input image into a globally well‐exposed image. Experiments on a number of challenging images demonstrate the effectiveness of the proposed approach and its superiority over the state‐of‐the‐art methods and popular automatic exposure correction tools.     

数学仿真模型的误差估计和校正(二)

给出数学仿真模型的时域误差估计和一些校正方法。     

加权质心定位误差的反向修正法

研究了距离因子g对加权质心定位算法(WCL)定位精度的影响,提出了全局最优g的选取方法。然后研究了未知节点自身位置对WCL算法定位精度的影响,并提出了一种基于估计位置和误差之间关系的反向(EB)修正法。仿真结果表明,全局最优g可以使质心附近区域的定位精度得到显著提高,但不能解决远离质心区域定位精度较差的问题,而EB修正法则可在保持质心附近区域定位精度的同时有效提高远离质心区域的定位精度。     

Probabilities of Failure for Quantum Error Correction

We investigate the performance of a quantum error-correcting code when pushed beyond its intended capacity to protect against errors, presenting formulae for the probability of failure when the errors affect more qudits than that specified by the code’s minimum distance. Such formulae provide a means to rank different codes of the same minimum distance. We consider both error detection and error correction, treating explicit examples in the case of stabilizer codes constructed from qubits and encoding a single qubit Pacs: 03.67.Pp     

适用于高误比特率信道的鲁棒信息隐藏

提出不需要原始图文件比对即可提取出隐藏信息的方法。作法是应用扩频信息隐藏技术,选取部分隐藏位置与加入错误修正编码和交错器,强化信息隐藏的强度,以JPEG压缩破坏、随机信道破坏与图像分割等方式来验证。实验结果显示,在JPEG压缩品质为80%,压缩率为16倍时,提取隐藏信息的误比特率在6%以内;随机信道破坏的破坏率在15%时,误比特率在13%以内;图像分割1/2时,误比特率在13%以内。表明该方法能提高信息隐藏在高误比特率信道的鲁棒性。     

Approximate Quantum Error Correction

The errors that arise in a quantum channel can be corrected perfectly if and only if the channel does not decrease the coherent information of the input state. We show that, if the loss of coherent information is small, then approximate quantum error correction is possible. PACS: 03.67.H, 03.65.U     

柔性三坐标测量臂几何误差修正

柔性三坐标测量臂用于大尺寸工件的高精度检测及逆向工程,是现代制造业产品精度检测的重要设备。如何做好和完善测量臂误差的分析、检测和补偿,成为提高测量臂测量精度的重要问题。提出了用高精度正交三坐标测量机校准柔性三坐标测量臂关节误差的新方法。通过分析测量臂某一关节的所有几何误差,建立其数学模型;利用正交三坐标测量机和测量臂分别对30个标准球(均匀分布在一个圆上)进行点位测量,测出球心的标称值和实测值,建立了该关节几何误差补偿模型;对工件进行点位测量并进行误差补偿。实验结果表明,通过该误差补偿方法,其最大测量误差从0.04 mm降到了0.003mm,提高了柔性三坐标测量臂的测量精度,同时验证了该误差补偿方法的正确性和有效性。     

General and Robust Error Estimation and Reconstruction for Monte Carlo Rendering

Adaptive filtering techniques have proven successful in handling non‐uniform noise in Monte‐Carlo rendering approaches. A recent trend is to choose an optimal filter per pixel from a selection of non spatially‐varying filters. Nonetheless, the best filter choice is difficult to predict in the absence of a reference rendering. Our approach relies on the observation that the reconstruction error is locally smooth for a given filter. Hence, we propose to construct a dense error prediction from a small set of sparse but robust estimates. The filter selection is then formulated as a non‐local optimization problem, which we solve via graph cuts, to avoid visual artifacts due to inconsistent filter choices. Our approach does not impose any restrictions on the used filters, outperforms previous state‐of‐the‐art techniques and provides an extensible framework for future reconstruction techniques.     

视图维护的并行在线错误纠正算法

最近几年,数据仓维护问题的重心已转移到各信息源并发更新下的视图维护。比较流行的算法,如ECA算法和Strobe算法在解决并发更新问题时需要数据仓处于静止状态。而文中的在线错误纠正方法不需要额外的本地补偿操作,并且在维护时不需要数据仓处于静止状态。进而该文提出了一个在线错误纠正的优化算法,称为并行在线错误纠正算法。该算法对原有的函数模块做了一定的修正和增强处理,并给出了修改了的函数功能模块图,它能完成并行维护,提高维护的性能。