密码学Simulation仿真（英语：simulation）或译作模拟，泛指基于实验或训练为目的，将原本的真实或抽象的选定系统或流程，建立一个模型以表征其关键特性（key characteristics）或者行为、功能，予以系统化与公式化，以便进行可对关键特征做出仿真。模型表示系统自身，而仿真表示系统的时序行为。 电脑仿真常被用来研究仿真模型（simulation model）。仿真也被用于对自然系统或人造系统的科学建模以获取深入理解。仿真可以用来展示可选条件或动作过程的最终结果。仿真也会用在因为无法接近、也可能太过于危险或不可接受的后果、或者设计了但还未建造、或者根本就不存在等原因而不能在真实的系统中达成的。仿真的关键是获取相关选定的关键特性与行为的有效信息源，仿真时使用简化的近似或者假定，仿真结果的保真度（fidelity）与有效性。模型验证（verification）与有效性（validation）的过程、协议是学术学习、改进、研究、开发仿真技术的热点，特别是对计算机仿真。 仿真保真度（Simulation Fidelity）用于描述仿真精度，模拟真实对应物有多近似： 低保真：对系统的最小模拟，接受输入产生输出 中等保真：对刺激能自动响应，有限精度 高保真：接近不可辨识或者尽可能地接近真实系统
A simulation is an imitative representation of a process or system that could exist in the real world. In this broad sense, simulation can often be used interchangeably with model. Sometimes a clear distinction between the two terms is made, in which simulations require the use of models; the model represents the key characteristics or behaviors of the selected system or process, whereas the simulation represents the evolution of the model over time. Another way to distinguish between the terms is to define simulation as experimentation with the help of a model. This definition includes time-independent simulations. Often, computers are used to execute the simulation. Simulation is used in many contexts, such as simulation of technology for performance tuning or optimizing, safety engineering, testing, training, education, and video games.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。
查看内容许可 ↗在数学中，特别是在代数域论中，正规基是有限次伽罗瓦扩展的一种特殊基，其特征在于形成伽罗瓦群的单个轨道。正规基定理指出，任何有限的伽罗瓦域扩展都具有正规基。在代数数论中，对正规积分基存在性的更精细问题的研究是伽罗瓦模理论的一部分。
In mathematics, specifically the algebraic theory of fields, a normal basis is a special kind of basis for Galois extensions of finite degree, characterised as forming a single orbit for the Galois group. The normal basis theorem states that any finite Galois extension of fields has a normal basis. In algebraic number theory, the study of the more refined question of the existence of a normal integral basis is part of Galois module theory.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗伯努利数 Bn 是一个数学分析中常见的有理数序列。前21个伯努利数的值列于右表。其中上标 ± 在本文中用来区别两种不同的伯努利数定义，这两种定义只对 n = 1 {\displaystyle n=1} 有区别： B 1 − = − 1 / 2 {\displaystyle B_{1}^{-{}}=-1/2} ， B 1 + = + 1 / 2 {\displaystyle B_{1}^{+{}}=+1/2} 。
In mathematics, the Bernoulli numbers Bn are a sequence of rational numbers which occur frequently in analysis. The Bernoulli numbers appear in (and can be defined by) the Taylor series expansions of the tangent and hyperbolic tangent functions, in Faulhaber's formula for the sum of m-th powers of the first n positive integers, in the Euler–Maclaurin formula, and in expressions for certain values of the Riemann zeta function. The values of the first 20 Bernoulli numbers are given in the adjacent table.
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查看内容许可 ↗在数学中，更准确地说在代数中，可解群（不太常见：可解群）是同构于可解群逆系统的逆极限的群。等价地，如果将一个群视为拓扑群，恒等的每个开邻域都包含一个正规子群，其对应的商群是可解群，则该群称为可解群。
In mathematics, more precisely in algebra, a prosolvable group (less common: prosoluble group) is a group that is isomorphic to the inverse limit of an inverse system of solvable groups. Equivalently, a group is called prosolvable, if, viewed as a topological group, every open neighborhood of the identity contains a normal subgroup whose corresponding quotient group is a solvable group.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在数学中，中国余数定理指出，如果知道一个整数n除以几个整数的欧几里得除法的余数，那么在除数成对互质（没有两个除数有除1之外的公因数）的条件下，可以唯一地确定n除以这些整数的乘积的余数。该定理有时称为孙子定理。该定理的两个名称均指其最早出现在《孙子算经》中的已知陈述，这是一部写于公元 3 至 5 世纪的中国手稿。
In mathematics, the Chinese remainder theorem states that if one knows the remainders of the Euclidean division of an integer n by several integers, then one can determine uniquely the remainder of the division of n by the product of these integers, under the condition that the divisors are pairwise coprime (no two divisors share a common factor other than 1). The theorem is sometimes called Sunzi's theorem. Both names of the theorem refer to its earliest known statement that appeared in Sunzi Suanjing, a Chinese manuscript written during the 3rd to 5th century CE.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗Diffie-Hellman (DH) 密钥交换是一种通过公共通道安全生成对称加密密钥的数学方法。它以 1976 年出版的 Whitfield Diffie 和 Martin Hellman 的名字命名。DH 是密码学领域最早实现的密钥交换的实际例子之一。传统上，两方之间的安全加密通信要求他们首先通过某种安全的物理方式交换密钥，例如由可信信使运输的纸质密钥列表。相比之下，Diffie-Hellman 密钥交换方法允许彼此互不了解的两方通过不安全的通道共同建立共享密钥。然后，该密钥可用于使用对称密钥密码来加密后续通信。
Diffie–Hellman (DH) key exchange is a mathematical method of securely generating a symmetric cryptographic key over a public channel. It is named after Whitfield Diffie and Martin Hellman who published it in 1976. DH is one of the earliest practical examples of key exchange implemented within the field of cryptography. Traditionally, secure encrypted communication between two parties required that they first exchange keys by some secure physical means, such as paper key lists transported by a trusted courier. By contrast, the Diffie–Hellman key exchange method allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure channel. This key can then be used to encrypt subsequent communications using a symmetric-key cipher.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗密钥交换（也称为密钥建立）是密码学中的一种方法，通过该方法在两方之间交换加密密钥，从而允许使用加密算法。如果发送方和接收方希望交换加密消息，则双方都必须具备对要发送的消息进行加密并对接收到的消息进行解密的能力。他们所需的设备的性质取决于他们可能使用的加密技术。如果他们使用密码，则两者都需要相同密码本的副本。如果他们使用密码，他们将需要适当的密钥。如果密码是对称密钥密码，则两者都需要相同密钥的副本。如果它是具有公钥/私钥属性的非对称密钥密码，则双方都需要对方的公钥。
Key exchange (also key establishment) is a method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm. If the sender and receiver wish to exchange encrypted messages, each must be equipped to encrypt messages to be sent and decrypt messages received. The nature of the equipping they require depends on the encryption technique they might use. If they use a code, both will require a copy of the same codebook. If they use a cipher, they will need appropriate keys. If the cipher is a symmetric key cipher, both will need a copy of the same key. If it is an asymmetric key cipher with the public/private key property, both will need the other's public key.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗活板门或舱口是与地板、天花板或屋顶表面齐平的滑动门或铰链门。传统上它的尺寸很小。它的发明是为了方便通过磨坊提升谷物，然而，随着时间的推移，它的用途不断增加。活板门在绞刑架、货船、火车、诱杀装置以及最近的戏剧和电影的操作中发挥了关键作用。
A trapdoor or hatch is a sliding or hinged door that is flush with the surface of a floor, ceiling, or roof. It is traditionally small in size. It was invented to facilitate the hoisting of grain up through mills, however, its list of uses has grown over time. The trapdoor has played a pivotal function in the operation of the gallows, cargo ships, trains, booby traps, and more recently theatre and films.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗椭圆曲线 Diffie-Hellman (ECDH) 是一种密钥协商协议，允许双方（每方都有一个椭圆曲线公钥-私钥对）通过不安全的通道建立共享密钥。该共享秘密可以直接用作密钥，或者派生另一个密钥。然后，该密钥或派生密钥可用于使用对称密钥密码来加密后续通信。它是使用椭圆曲线加密技术的 Diffie–Hellman 协议的变体。
Elliptic-curve Diffie–Hellman (ECDH) is a key agreement protocol that allows two parties, each having an elliptic-curve public–private key pair, to establish a shared secret over an insecure channel. This shared secret may be directly used as a key, or to derive another key. The key, or the derived key, can then be used to encrypt subsequent communications using a symmetric-key cipher. It is a variant of the Diffie–Hellman protocol using elliptic-curve cryptography.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗基于格的密码学是涉及格的密码原语构造的通用术语，无论是在构造本身还是在安全证明中。基于格的结构支持后量子密码学的重要标准。与更广泛使用和已知的公钥方案（例如 RSA、Diffie-Hellman 或椭圆曲线密码系统）不同（理论上可以在量子计算机上使用 Shor 算法来击败这些方案），一些基于晶格的结构似乎可以抵抗经典计算机和量子计算机的攻击。此外，在某些经过充分研究的计算格问题无法有效解决的假设下，许多基于格的构造被认为是安全的。 2024 年，NIST 宣布了后量子密码学的基于模块格的数字签名标准。
Lattice-based cryptography is the generic term for constructions of cryptographic primitives that involve lattices, either in the construction itself or in the security proof. Lattice-based constructions support important standards of post-quantum cryptography. Unlike more widely used and known public-key schemes such as the RSA, Diffie-Hellman or elliptic-curve cryptosystems—which could, theoretically, be defeated using Shor's algorithm on a quantum computer—some lattice-based constructions appear to be resistant to attack by both classical and quantum computers. Furthermore, many lattice-based constructions are considered to be secure under the assumption that certain well-studied computational lattice problems cannot be solved efficiently. In 2024 NIST announced the Module-Lattice-Based Digital Signature Standard for post-quantum cryptography.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在密码学中，错误学习 (LWE) 是一个广泛用于创建安全加密算法的数学问题。它基于将秘密信息表示为一组有错误的方程的思想。换句话说，LWE 是一种通过引入噪声来隐藏秘密值的方法。用更专业的术语来说，它指的是从给定样本 y i = f ( x i ) {\displaystyle y_{i}=f(\mathbf {x} _{i})} 在有限环上推断线性 n {\displaystyle n} -ary 函数 f {\displaystyle f} 的计算问题，其中一些可能是错误的。 LWE 问题被认为很难解决，因此在密码学中很有用。更准确地说，LWE 问题定义如下。
In cryptography, learning with errors (LWE) is a mathematical problem that is widely used to create secure encryption algorithms. It is based on the idea of representing secret information as a set of equations with errors. In other words, LWE is a way to hide the value of a secret by introducing noise to it. In more technical terms, it refers to the computational problem of inferring a linear n {\displaystyle n} -ary function f {\displaystyle f} over a finite ring from given samples y i = f ( x i ) {\displaystyle y_{i}=f(\mathbf {x} _{i})} some of which may be erroneous. The LWE problem is conjectured to be hard to solve, and thus to be useful in cryptography. More precisely, the LWE problem is defined as follows.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗后量子密码学 (PQC)，有时被称为量子证明、量子安全或抗量子，是密码算法（通常是公钥算法）的发展，目前认为但尚未证明可以安全地抵御量子计算机的密码分析攻击。最广泛使用的公钥算法依赖于三个数学问题之一的难度：整数分解问题、离散对数问题或椭圆曲线离散对数问题。所有这些问题都可以在运行肖尔算法或可能的替代算法的足够强大的量子计算机上轻松解决。
Post-quantum cryptography (PQC), sometimes referred to as quantum-proof, quantum-safe, or quantum-resistant, is the development of cryptographic algorithms (usually public-key algorithms) that are currently thought, but not proven, to be secure against a cryptanalytic attack by a quantum computer. Most widely used public-key algorithms rely on the difficulty of one of three mathematical problems: the integer factorization problem, the discrete logarithm problem, or the elliptic-curve discrete logarithm problem. All of these problems could be easily solved on a sufficiently powerful quantum computer running Shor's algorithm or possibly alternatives.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在硬件和软件系统的背景下，形式验证是使用形式数学方法证明或反驳系统在特定形式规范或属性方面的正确性的行为。形式化验证是系统形式化规范的关键激励因素，也是形式化方法的核心。它代表了电子设计自动化中分析和验证的一个重要维度，并且是软件验证的一种方法。使用形式验证可在计算机安全认证通用标准框架内实现最高评估保证级别 (EAL7)。形式验证有助于证明系统的正确性，例如：密码协议、组合电路、带内部存储器的数字电路以及以编程语言表示为源代码的软件。
In the context of hardware and software systems, formal verification is the act of proving or disproving the correctness of a system with respect to a certain formal specification or property, using formal methods of mathematics. Formal verification is a key incentive for formal specification of systems, and is at the core of formal methods. It represents an important dimension of analysis and verification in electronic design automation and is one approach to software verification. The use of formal verification enables the highest Evaluation Assurance Level (EAL7) in the framework of common criteria for computer security certification. Formal verification can be helpful in proving the correctness of systems such as: cryptographic protocols, combinational circuits, digital circuits with internal memory, and software expressed as source code in a programming language.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在理论计算机科学中，时间复杂度是描述运行算法所需的计算机时间量的计算复杂度。时间复杂度通常通过计算算法执行的基本操作的数量来估计，假设每个基本操作需要固定的时间来执行。因此，算法所花费的时间量和执行的基本运算的数量被认为与常数因子相关。由于算法的运行时间可能因相同大小的不同输入而异，因此通常考虑最坏情况的时间复杂度，即给定大小的输入所需的最大时间量。
In theoretical computer science, the time complexity is the computational complexity that describes the amount of computer time it takes to run an algorithm. Time complexity is commonly estimated by counting the number of elementary operations performed by the algorithm, supposing that each elementary operation takes a fixed amount of time to perform. Thus, the amount of time taken and the number of elementary operations performed by the algorithm are taken to be related by a constant factor. Since an algorithm's running time may vary among different inputs of the same size, one commonly considers the worst-case time complexity, which is the maximum amount of time required for inputs of a given size.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗再现性与可重复性和可重复性密切相关，是支撑科学方法的主要原则。研究结果的可重复性意味着，当研究被重复时，通过实验或观察性研究或数据集统计分析获得的结果应该再次获得高度的可靠性。复制有不同类型，但复制研究通常涉及使用相同方法的不同研究人员。只有在一次或多次成功复制之后，结果才能被视为科学知识。
Reproducibility, closely related to replicability and repeatability, is a major principle underpinning the scientific method. For the findings of a study to be reproducible means that results obtained by an experiment or an observational study or in a statistical analysis of a data set should be achieved again with a high degree of reliability when the study is replicated. There are different kinds of replication but typically replication studies involve different researchers using the same methodology. Only after one or several such successful replications should a result be recognized as scientific knowledge.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在编码理论、电信工程和其他相关工程问题中，编码增益是与纠错码 (ECC) 一起使用时达到相同误码率 (BER) 水平所需的未编码系统和编码系统之间的信噪比 (SNR) 水平差异的度量。
In coding theory, telecommunications engineering and other related engineering problems, coding gain is the measure in the difference between the signal-to-noise ratio (SNR) levels between the uncoded system and coded system required to reach the same bit error rate (BER) levels when used with the error correcting code (ECC).
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗密码学或密码学是在存在对抗行为的情况下安全通信技术的实践和研究。更一般地说，密码学是关于构建和分析防止第三方或公众阅读私人消息的协议。现代密码学存在于数学、计算机科学、信息安全、电气工程、数字信号处理、物理学等学科的交叉点。与信息安全相关的核心概念（数据机密性、数据完整性、身份验证和不可否认性）也是密码学的核心。密码学的实际应用包括电子商务、基于芯片的支付卡、数字货币、计算机密码和军事通信。
Cryptography, or cryptology, is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security (data confidentiality, data integrity, authentication and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords and military communications.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗对称密钥算法是使用相同的密钥来加密明文和解密密文的加密算法。这些密钥可以是相同的，或者两个密钥之间可以进行简单的转换。实际上，密钥代表两方或多方之间的共享秘密，可用于维护私有信息链接。与非对称密钥加密（也称为公钥加密）相比，要求双方都可以访问密钥是对称密钥加密的主要缺点之一。然而，对称密钥加密算法通常更适合批量加密。除了一次性一密本之外，它们的密钥尺寸更小，这意味着存储空间更小，传输速度更快。
Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for both the encryption of plaintext and the decryption of ciphertext. The keys may be identical, or there may be a simple transformation to go between the two keys. The keys, in practice, represent a shared secret between two or more parties that can be used to maintain a private information link. The requirement that both parties have access to the secret key is one of the main drawbacks of symmetric-key encryption, in comparison to asymmetric-key encryption (also known as public-key encryption). However, symmetric-key encryption algorithms are usually better for bulk encryption. With the exception of the one-time pad they have a smaller key size, which means less storage space and faster transmission.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗公钥密码术或非对称密码术是使用相关密钥对的密码系统领域。每个密钥对由一个公钥和一个相应的私钥组成。密钥对是通过基于称为单向函数的数学问题的算法生成的。公钥密码学的安全性取决于私钥的保密；公钥可以公开分发，而不会影响安全性。公钥密码系统有很多种，具有不同的安全目标，包括数字签名、Diffie-Hellman 密钥交换、公钥密钥封装和公钥加密。公钥算法是现代密码系统中的基本安全原语，包括保证电子通信和数据存储的机密性和真实性的应用程序和协议。
Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys. Each key pair consists of a public key and a corresponding private key. Key pairs are generated with algorithms based on mathematical problems termed one-way functions. Security of public-key cryptography depends on keeping the private key secret; the public key can be openly distributed without compromising security. There are many kinds of public-key cryptosystems, with different security goals, including digital signature, Diffie–Hellman key exchange, public-key key encapsulation, and public-key encryption. Public key algorithms are fundamental security primitives in modern cryptosystems, including applications and protocols that offer assurance of the confidentiality and authenticity of electronic communications and data storage.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在密码学中，分组密码是一种确定性算法，它对固定长度的位组（称为块）进行操作。分组密码是许多加密协议的基本构建块。它们在数据存储和交换中无处不在，这些数据通过加密来保护和验证。分组密码使用分组作为不变的变换。即使安全分组密码也适用于使用固定密钥一次仅加密单个数据块。多种操作模式的设计允许以安全的方式重复使用它们，以实现机密性和真实性的其他安全目标。然而，分组密码也可以作为其他加密协议中的构建块，例如通用哈希函数和伪随机数生成器。
In cryptography, a block cipher is a deterministic algorithm that operates on fixed-length groups of bits, called blocks. Block ciphers are the elementary building blocks of many cryptographic protocols. They are ubiquitous in the storage and exchange of data, where such data is secured and authenticated via encryption. A block cipher uses blocks as an unvarying transformation. Even a secure block cipher is suitable for the encryption of only a single block of data at a time, using a fixed key. A multitude of modes of operation have been designed to allow their repeated use in a secure way to achieve the other security goals of confidentiality and authenticity. However, block ciphers may also feature as building blocks in other cryptographic protocols, such as universal hash functions and pseudorandom number generators.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗流密码是一种对称密钥密码，其中明文数字与伪随机密码数字流（密钥流）相结合。在流密码中，每个明文数字一次用密钥流的相应数字加密，以给出密文流的数字。由于每个数字的加密取决于密码的当前状态，因此也称为状态密码。实际上，一个数字通常是一个位，组合操作是异或 (XOR)。伪随机密钥流通常是使用数字移位寄存器从随机种子值串行生成的。种子值用作解密密文流的密钥。流密码代表了与分组密码不同的对称加密方法。分组密码通过固定不变的变换对大数字块进行操作。
A stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream (keystream). In a stream cipher, each plaintext digit is encrypted one at a time with the corresponding digit of the keystream, to give a digit of the ciphertext stream. Since encryption of each digit is dependent on the current state of the cipher, it is also known as state cipher. In practice, a digit is typically a bit and the combining operation is an exclusive-or (XOR). The pseudorandom keystream is typically generated serially from a random seed value using digital shift registers. The seed value serves as the cryptographic key for decrypting the ciphertext stream. Stream ciphers represent a different approach to symmetric encryption from block ciphers. Block ciphers operate on large blocks of digits with a fixed, unvarying transformation.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在数学中，排列是一个集合到其自身的双射。它可以被解释为序列或线性顺序的成员的新顺序，或者被解释为改变有序集合的线性顺序的行为或过程。第一种解释的示例是集合 {1, 2, 3} 的六个排列，即六个 3 元组 (1, 2, 3)、(1, 3, 2)、(2, 1, 3)、(2, 3, 1)、(3, 1, 2) 和 (3, 2, 1)。它们对应于将 1、2、3 分别映射到元组的第一个、第二个和第三个成员的六个双射。字母全部不同的单词的字谜词也是排列：字母已经在原始单词中排序，字谜词重新排序它们。有限集排列的研究是组合数学和群论中的一个重要课题。排列几乎用于数学的每个分支和许多其他科学领域。
In mathematics, a permutation is a bijection of a set onto itself. It can be interpreted as a new order of the members of a sequence or linear order, or as the act or process of changing the linear order of an ordered set. An example of the first interpretation is the six permutations of the set {1, 2, 3}, which are the six 3-tuples (1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), and (3, 2, 1). They correspond to the six bijections that map 1, 2, 3, to the first, the second and the third member of the tuple, respectively. Anagrams of a word whose letters are all different are also permutations: the letters are already ordered in the original word, and the anagram reorders them. The study of permutations of finite sets is an important topic in combinatorics and group theory. Permutations are used in almost every branch of mathematics and in many other fields of science.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在密码学中，S 盒（替换盒）是执行替换的对称密钥算法的基本组件。在分组密码中，它们通常用于模糊密钥和密文之间的关系，从而确保香农的混淆性。从数学上讲，S 盒是非线性矢量布尔函数。一般来说，S 盒采用一定数量的输入位 m，并将它们转换为一定数量的输出位 n，其中 n 不一定等于 m。 m×n S 盒可以实现为具有 2 个字（每个字有 n 位）的查找表。通常使用固定表，如数据加密标准 (DES)，但在某些密码中，表是根据密钥动态生成的（例如 Blowfish 和 Twofish 加密算法）。固定表的一个很好的例子是 DES (S5) 中的 S 盒，它将 6 位输入映射到 4 位输出：
In cryptography, an S-box (substitution-box) is a basic component of symmetric key algorithms which performs substitution. In block ciphers, they are typically used to obscure the relationship between the key and the ciphertext, thus ensuring Shannon's property of confusion. Mathematically, an S-box is a nonlinear vectorial Boolean function. In general, an S-box takes some number of input bits, m, and transforms them into some number of output bits, n, where n is not necessarily equal to m. An m×n S-box can be implemented as a lookup table with 2 words of n bits each. Fixed tables are normally used, as in the Data Encryption Standard (DES), but in some ciphers the tables are generated dynamically from the key (e.g. the Blowfish and the Twofish encryption algorithms). One good example of a fixed table is the S-box from DES (S5), mapping 6-bit input into a 4-bit output:
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗Salsa20（以前称为 Snuffle 2005）和密切相关的 ChaCha 是 Daniel J. Bernstein 开发的流密码。 Salsa20 是最初的密码，于 2005 年设计，后来由 Bernstein 提交给 eSTREAM 欧盟密码验证流程。 ChaCha 是 2008 年发布的 Salsa20 的修改版。它使用了新的轮函数，可以增加扩散并提高某些架构上的性能。两种密码均建立在基于加法旋转异或 (ARX) 操作的伪随机函数之上，即 32 位加法、按位加法 (XOR) 和旋转操作。核心函数将 256 位密钥、64 位随机数和 64 位计数器映射到密钥流的 512 位块（也存在具有 128 位密钥的 Salsa 版本）。这给Salsa20和ChaCha带来了不寻常的优势，即用户可以在恒定的时间内有效地寻找密钥流中的任何位置。
Salsa20 (formerly known as Snuffle 2005) and the closely related ChaCha are stream ciphers developed by Daniel J. Bernstein. Salsa20, the original cipher, was designed in 2005, then later submitted to the eSTREAM European Union cryptographic validation process by Bernstein. ChaCha is a modification of Salsa20 published in 2008. It uses a new round function that increases diffusion and increases performance on some architectures. Both ciphers are built on a pseudorandom function based on add–rotate–XOR (ARX) operations — 32-bit addition, bitwise addition (XOR) and rotation operations. The core function maps a 256-bit key, a 64-bit nonce, and a 64-bit counter to a 512-bit block of the key stream (a Salsa version with a 128-bit key also exists). This gives Salsa20 and ChaCha the unusual advantage that the user can efficiently seek to any position in the key stream in constant time.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在密码学中，初始化向量 (IV) 或起始变量是用于提供初始状态的密码原语的输入。通常要求 IV 是随机或伪随机的，但有时 IV 只需要不可预测或唯一。随机化对于某些加密方案实现语义安全至关重要，这是一种在同一密钥下重复使用该方案的属性，不允许攻击者推断加密消息的（可能相似的）片段之间的关系。对于分组密码，IV 的使用由操作模式来描述。一些密码原语仅要求 IV 不重复，并且所需的随机性是在内部导出的。在这种情况下，IV 通常称为随机数（仅使用一次的数字），并且原语（例如 CBC）被认为是有状态的而不是随机的。
In cryptography, an initialization vector (IV) or starting variable is an input to a cryptographic primitive being used to provide the initial state. The IV is typically required to be random or pseudorandom, but sometimes an IV only needs to be unpredictable or unique. Randomization is crucial for some encryption schemes to achieve semantic security, a property whereby repeated usage of the scheme under the same key does not allow an attacker to infer relationships between (potentially similar) segments of the encrypted message. For block ciphers, the use of an IV is described by the modes of operation. Some cryptographic primitives require the IV only to be non-repeating, and the required randomness is derived internally. In this case, the IV is commonly called a nonce (a number used only once), and the primitives (e.g. CBC) are considered stateful rather than randomized.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在密码学中，所谓的乘积密码是一种特定类型的密码，其中数据的（解密）加密通常通过轮次迭代来完成。每轮的设置通常是相同的，除了称为轮常量的轮特定固定值和从称为轮密钥的密码密钥派生的轮特定数据之外。密钥调度是一种根据密钥计算所有轮密钥的算法。 Knudsen 和 Mathiassen (2004) 给出了一些实验证据，表明密钥调度在提供对抗线性和差分密码分析的强度方面发挥了一定作用。对于玩具 Feistel 密码，据观察，那些具有复杂且设计良好的密钥调度的密码可以比那些设计不良的密钥调度的密码更快地达到差分和线性包的概率的均匀分布。
In cryptography, the so-called product ciphers are a certain kind of cipher, where the (de-)ciphering of data is typically done as an iteration of rounds. The setup for each round is generally the same, except for round-specific fixed values called a round constant, and round-specific data derived from the cipher key called a round key. A key schedule is an algorithm that calculates all the round keys from the key. Knudsen and Mathiassen (2004) give some experimental evidence that indicate that the key schedule plays a part in providing strength against linear and differential cryptanalysis. For toy Feistel ciphers, it was observed that those with complex and well-designed key schedules can reach a uniform distribution for the probabilities of differentials and linear hulls faster than those with poorly designed key schedules.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在密码学中，明文通常意味着未加密的信息等待输入到密码算法（通常是加密算法）中。这通常是指未加密传输或存储的数据。随着计算的出现，术语“明文”超出了人类可读的文档范围，意味着任何数据，包括二进制文件，其形式可以在不需要密钥或其他解密设备的情况下查看或使用。信息（消息、文档、文件等）如果以未加密的形式进行通信或存储，则称为明文。明文用作加密算法的输入；输出通常称为密文，特别是当算法是密码时。代码文本很少使用，并且几乎总是仅当涉及的算法实际上是代码时才使用。
In cryptography, plaintext usually means unencrypted information pending input into cryptographic algorithms, usually encryption algorithms. This usually refers to data that is transmitted or stored unencrypted. With the advent of computing, the term plaintext expanded beyond human-readable documents to mean any data, including binary files, in a form that can be viewed or used without requiring a key or other decryption device. Information—a message, document, file, etc.—if to be communicated or stored in an unencrypted form is referred to as plaintext. Plaintext is used as input to an encryption algorithm; the output is usually termed ciphertext, particularly when the algorithm is a cipher. Codetext is less often used, and almost always only when the algorithm involved is actually a code.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗在密码学中，密文或密文是使用称为密码的算法对明文执行加密的结果。密文也称为加密或编码信息，因为它包含原始明文的一种形式，如果没有适当的密码来解密，人类或计算机就无法读取它。此过程可防止因黑客攻击而丢失敏感信息。解密是加密的逆过程，是将密文转换为可读明文的过程。密文不应与代码文本混淆，因为后者是代码的结果，而不是密码。令 m {\displaystyle m\!} 为 Alice 想要秘密传输给 Bob 的明文消息，令 E k {\displaystyle E_{k}\!} 为加密密码，其中 k {\displaystyle _{k}\!} 为加密密钥。
In cryptography, ciphertext or cyphertext is the result of encryption performed on plaintext using an algorithm, called a cipher. Ciphertext is also known as encrypted or encoded information because it contains a form of the original plaintext that is unreadable by a human or computer without the proper cipher to decrypt it. This process prevents the loss of sensitive information via hacking. Decryption, the inverse of encryption, is the process of turning ciphertext into readable plaintext. Ciphertext is not to be confused with codetext, because the latter is a result of a code, not a cipher. Let m {\displaystyle m\!} be the plaintext message that Alice wants to secretly transmit to Bob and let E k {\displaystyle E_{k}\!} be the encryption cipher, where k {\displaystyle _{k}\!} is a cryptographic key.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗认证加密 (AE) 是同时确保数据机密性（也称为隐私：在不知道密钥的情况下无法理解加密消息）和真实性（换句话说，它是不可伪造的：加密消息包括发送者只有在拥有密钥时才能计算的身份验证标签）的任何加密方案。提供 AE 的加密模式的示例有 GCM 和 CCM。许多（但不是全部）AE 方案允许消息包含“关联数据”（AD），该数据不保密，但受到完整性保护（即可读，但防篡改）。一个典型的例子是包含其目标地址的网络数据包的标头。为了正确路由数据包，消息路径中的所有中间节点都需要知道目的地，但出于安全原因，它们不能拥有密钥。
Authenticated encryption (AE) is any encryption scheme which simultaneously assures the data confidentiality (also known as privacy: the encrypted message is impossible to understand without the knowledge of a secret key) and authenticity (in other words, it is unforgeable: the encrypted message includes an authentication tag that the sender can calculate only while possessing the secret key). Examples of encryption modes that provide AE are GCM and CCM. Many (but not all) AE schemes allow the message to contain "associated data" (AD) which is not made confidential, but is integrity protected (i.e., readable, but tamperevident). A typical example is the header of a network packet that contains its destination address. To properly route the packet, all intermediate nodes in the message path need to know the destination, but for security reasons they cannot possess the secret key.
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维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
查看内容许可 ↗衬垫是薄的缓冲材料，有时添加到衣服上。当用作衬里被子中的层或用作包装或填充材料时，衬垫也可称为棉絮或棉絮。当在衣服中使用衬垫时，通常是为了减轻对身体某些区域的影响或通过增加身体特征的尺寸来增强外观。在时尚界，填充物有： Bombast，由马毛、羊绒、麸皮、羊毛、碎布或棉花组成，是 1600 年左右西欧用于为某些时尚服装提供所需体积的填充物。它特别用于男士的长筒软管，但也用于女士的长筒或炮袖 (1575-1620)。添加一些填充物是为了强调特定的物理特征。
Padding is thin cushioned material sometimes added to clothes. Padding may also be referred to as batting or wadding when used as a layer in lining quilts or as a packaging or stuffing material. When padding is used in clothes, it is often done in an attempt to soften impacts on certain zones of the body or enhance appearance by adding size to a physical feature. In fashion, there is padding for: Bombast, consisting of horsehair, flock, bran, wool, rags, or cotton, was the padding used to give the required bulk to certain fashionable items of dress in Western Europe around 1600. It was used in particular for men's trunk hose, but also for women's trunk or cannon sleeves (1575–1620). Some padding is added to emphasize particular physical features.
来源、授权与使用说明
维基百科条目作者 · 获取于 2026-10-04 · CC BY-SA 4.0。简介经过纯文本提取与截取；两个语言版本的内容侧重可能不同。用于概念速查，不替代标准原文。 本条中文为英文百科简介的机器辅助翻译，请结合英文原文核对专业术语。
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