共查询到20条相似文献，搜索用时 93 毫秒
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DSA数字签名算法是使用公开密钥，为接受验证数据的完整性和数据发送的身份。本以DSA算法为基础设计了群体肓数字签名和自证明公钥签名两种签名方案。 相似文献
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数字签名是一种以电子形式存储消息签名的方法,签名后的消息能够通过计算机网络来传输．尽管目前很多数字签名方案被提出,然而绝大部分方案缺乏安全性证明,很多方案在后来都被发现存在各种问题．本文介绍了一个可证明安全的数字签名方案一加载随机预言模型的全域Hash签名方案,并在给定公钥且能获得随机预言的情况下,对伪造签名的可能性作出了详细分析和证明．并给出了一个完美的FDH-Invert算法,求逆算法的有效性依赖于使用尽可能少的Hash查询找到伪造签名的FDH—Forge算法的能力． 相似文献
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零知识证明协议按照实现的不同方式可以分成密码学方法的零知识证明协议和物理方法的零知识证明协议.与密码学方法的零知识证明协议相比较,物理方法的零知识证明协议简单明了,更容易被不具备密码学专业知识者所理解和接受,而无需借助计算机的帮助.本文在对经典的阿里巴巴山洞的零知识证明问题分析的基础上,又给出了几类问题物理方法的零知识证明方案,并进行了相应的分析. 相似文献
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提出一个改进的无可信中心的(t,n)门限签名方案,并进行了正确性证明,最后分析了其安全性能.新方案的安全性依赖于椭圆曲线上离散对数的分解难度和椭圆曲线数字签名方案的安全性,且该方案能够抵抗合谋攻击. 相似文献
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介绍了椭圆曲线加密机制和数字签名技术的原理,通过对椭圆曲线加密和数字签名算法的分析,提出了一种基于ECC加密算法的数字签名方案,其安全性是基于求解椭圆曲线离散对数问题的,可在保持与RSA或DSA体制同样的安全性的前提下缩短密钥长度、降低通信成本、提高网络信息的安全性。 相似文献
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林立忠 《宁德师专学报(自然科学版)》2008,20(4):404-407
有关数字签名的应用已经深入社会生活的许多领域,而各类的应用环境又对数字签名提出了多种额外要求．这些要求使数字签名的应用已从最初作为手写签名的数字对照物拓展到多个领域,形成了具有多种用途的特殊数字签名．基于G．Ateniese和G．Tsudik提出的群签名方案（简称ACJT方案）,构造一个新的改进方案,新方案的构造过程使用了更为高效的知识签名协议,新方案的安全性在随机语言模型下得到了较为充分的分析． 相似文献
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为了提高数字签名方案的安全强度,设计了一个同时基于2个难解问题的数字签名方案.离散对数问题和因式分解问题是密码学中2个著名的难解问题,融合基于离散对数难题的ElGamal数字签名方案和基于因式分解难题的OSS数字签名方案,提出了一种安全性同时基于离散对数问题和因式分解问题的数字签名方案.安全分析得出在一个难题被解的情况下该方案仍然是安全的.与已有的类似方案比较,所提出的签名方案具有更短的签名长度,更低的存储开销和计算开销. 相似文献
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基于强RSA假设对Marc Fischlin数字签名方案进行了改进,改进方案当中的随机比特串及无碰撞的函数值均比Marc Fischlin数字签名方案缩短了一个比特.在安全性讨论中,改进方案的安全性仍归约为强RSA假定,且安全性证明不依赖于随机预言机模型.由于该文将异或运算改为了加法运算,因而使得改进后的数字签名方案有了更加广泛的应用,特别适用于分布式密码系统中的可验证签名分享. 相似文献
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随着信息技术的快速发展,信息安全问题已成为一个重要的研究课题。在信息安全的人才培养中,信息安全实训教学不可忽视。本文对信息安全中特殊性质数字签名的实训教学进行了初步探究,提出了一个数字签名方案并将其应用于实训教学中,对职业技术教育中信息安全人才教育改革进行探索与尝试。 相似文献
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Chris Du Feu 《Teaching Statistics》2009,31(3):66-71
A classroom practical exercise exploring the reliability of a basic capture‐mark‐recapture method of population estimation is described using great whale conservation as a starting point. Various teaching resources are made available. 相似文献
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张红旗 《廊坊师范学院学报》2010,(3):80-83
公推直选乡镇长与乡镇党委书记出现的时间、发展现状与趋势、制度依据、选举成本,以及乡镇长与乡镇党委书记在乡镇政权中的作用有明显的不同。在我们看来,直接选举乡镇党委书记,发展的空间更广阔,对乡镇民主建设与乡镇政府职能转型所起的作用更大。 相似文献
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乔南 《中学数学教学参考》2008,(11)
Vectors may also be multiplied by a number. The productof the vector a by the number λ is defined as the vector a λ=λa, the absolute value of which is obtained by multiplying theabsolute value of the vector a by the absolute value of thenumber λ, i. e. |λa|=|λ||a|, the direction coinciding withthe direction of the vector a or being in the opposite sensedepending on whether λ>0 or λ<0. If λ=0 or a=0, then λ a 相似文献
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（参考译文）。
向量也可和数做乘法．向量a与数字A的乘积定义为向量aλ—λa,它的绝对值是向量a的绝对值和数字A的绝对值的乘积, 相似文献
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The concept of metacognition refers to one’s knowledge and control of one’s own cognitive system. However, despite being widely
used, this concept is confusing because of several reasons. First, sometimes it is not at all clear what is cognitive and
what is metacognitive. Second, researchers often use the same term, namely, “metacognition” even when they refer to very different
aspects of this complex concept. Alternatively, researchers may use different terms to indicate the same metacognitive elements.
Another foggy matter is the interrelationships among the various components of metacognition discussed in the literature.
This conceptual confusion regarding the concept of metacognition and its sub-components calls for in-depth theoretical and
conceptual clarifications. The goal of this article is to portray a detailed example of a conceptual analysis of meta-strategic
knowledge (MSK) which is one specific component of metacognition. This specific example is used to draw a general model for
conceptual analyses of additional metacognitive components. The approach suggested here is to begin with a clear definition
of the target sub component of metacognition, followed by a systematic examination of this sub component according to several
dimensions that are relevant to metacognition in general and to that sub component in particular. The examination should include
an analysis of how the details of the definition of the target sub-component refer to: (a) general theoretical metacognitive
issues raised by prominent scholars; (b) definitions formulated and issues raised by other researchers who have investigated
the same (or a similar) sub-component and, (c) empirical findings pertaining to that sub-component. Finally, it should be
noted that since metacognition is a relational rather than a definite concept it is important to situate the context within
which the conceptual analysis takes place. 相似文献
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McSweeney and her colleagues (e.g., McSweeney, Hatfield, & Allen, 1990) have demonstrated reliable, large magnitude rate changes in maintained operants within daily sessions under a wide variety of reinforcement schedules. The present paper examined the role of schedule of reinforcement, reinforcement rate, and total amount of food access in determining those within-session rate changes. When median rates across birds were considered, all procedures resulted in a brief period of an increasing rate, followed by a modest rate loss across the major portion of the session. However, not all individuals exhibited that pattern. When the amount of food access per session was limited by lower reinforcement rates, shorter sessions, or shorter reinforcement durations, the magnitude of the withinsession rate change was reduced from that occurring without those constraints. Additionally, under the conditions that produced strong within-session rate changes, the magnitude of the within-session rate loss was correlated with the bird’s body weight. These effects are consistent with what is typically labeledsatiation. 相似文献
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The term professional vision points to the many nuanced ways professionals see. This paper traces the development of a professional vision of a researcher and a teacher looking at classroom practices. The researcher’s interest was to capture and study notable aspects of the teacher’s practice. Through a coding scheme, disparate classroom events were organized and analyzed to yield a researcher’s professional vision of the teacher’s practices. For the teacher, through reviewing the video records of his own classroom practices, his professional vision provided a basis for him to reflect and develop professionally. Leveraging on the work of the researcher, he initiated and transformed his own practices. Their collaboration yielded a mutually informed development of professional vision of classroom practices. In juxtaposing the two developments, the researcher and the teacher’s views can be contrasted, their distinctive interests highlighted and common grounds explored. Some implications for developing professional vision are drawn, and it is in the common grounds of the teacher’s professional development and seeing with a goal of enhancing of student learning that hold some promise of a mutual interest in developing a professional vision of classroom practices. 相似文献