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Accumulator (cryptography)
In cryptography, an accumulator is a one way membership hash function. It allows users to certify that potential candidates are a member of a certain set without revealing the individual members of the set. This concept was formally introduced by Josh Benaloh and Michael de Mare in 1993. Formal definitions There are several formal definitions which have been proposed in the literature. This section lists them by proposer, in roughly chronological order. Benaloh and de Mare (1993) Benaloh and de Mare define a one-way hash function as a family of functions h_: X_\times Y_\to Z_ which satisfy the following three properties: # For all \ell\in\mathbb, x\in X_, y\in Y_, one can compute h_(x,y) in time \text(\ell, , x, , , y, ). (Here the "poly" symbol refers to an unspecified, but fixed, polynomial.) # No probabilistic polynomial-time algorithm will, for sufficiently large \ell, map the inputs \ell\in\mathbb, (x, y)\in X_\times Y_, y'\in Y_, find a value x'\in X_ such that h_(x, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or ''-logy, -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of Adversary (cryptography), adversarial behavior. More generally, cryptography is about constructing and analyzing Communication protocol, 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 (confidentiality, data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, Smart card#EMV, chip-based payment cards, digital currencies, password, computer passwords, and military communications. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitwise And
In computer programming, a bitwise operation operates on a bit string, a bit array or a binary numeral (considered as a bit string) at the level of its individual bits. It is a fast and simple action, basic to the higher-level arithmetic operations and directly supported by the processor. Most bitwise operations are presented as two-operand instructions where the result replaces one of the input operands. On simple low-cost processors, typically, bitwise operations are substantially faster than division, several times faster than multiplication, and sometimes significantly faster than addition. While modern processors usually perform addition and multiplication just as fast as bitwise operations due to their longer instruction pipelines and other architectural design choices, bitwise operations do commonly use less power because of the reduced use of resources. Bitwise operators In the explanations below, any indication of a bit's position is counted from the right (least sig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from "hidden, secret"; and ''graphein'', "to write", or ''-logy, -logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of Adversary (cryptography), adversarial behavior. More generally, cryptography is about constructing and analyzing Communication protocol, 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 (confidentiality, data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, Smart card#EMV, chip-based payment cards, digital currencies, password, computer passwords, and military communications. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zcash
Zcash is a privacy-focused cryptocurrency based on Bitcoin's codebase. It shares many similarities, such as a fixed total supply of 21 million units. Transactions can be transparent, similar to bitcoin transactions, or they can be shielded transactions which use a type of zero-knowledge proof to provide anonymity in transactions. Zcash coins are either in a transparent pool or a shielded pool. Zcash offers private transactors the option of "selective disclosure," allowing users to prove payment for auditing purposes. One such reason is to make it easier for private transactors to comply with anti-money laundering laws and tax regulations. Use Zcash transactions can be transparent, similar to bitcoin transactions, in which case they are controlled by a "t-addr" or shielded and controlled by a "z-addr." A shielded transaction uses a type of zero-knowledge proof, specifically a non-interactive zero-knowledge proof, called "zk-SNARK," which provides anonymity to the coin hold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-interactive Zero-knowledge Proof
Across the many fields concerned with interactivity, including information science, computer science, human-computer interaction, communication, and industrial design, there is little agreement over the meaning of the term "interactivity", but most definitions are related to interaction between users and computers and other machines through a user interface. Interactivity can however also refer to interaction between people. It nevertheless usually refers to interaction between people and computers – and sometimes to interaction between computers – through software, hardware, and networks. Multiple views on interactivity exist. In the "contingency view" of interactivity, there are three levels: #Not interactive, when a message is not related to previous messages. #Reactive, when a message is related only to one immediately previous message. #Interactive, when a message is related to a number of previous messages and to the relationship between them. One body of research h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptographic Commitment
A commitment scheme is a cryptographic primitive that allows one to commit to a chosen value (or chosen statement) while keeping it hidden to others, with the ability to reveal the committed value later.Oded Goldreich (2001). Foundations of Cryptography': Volume 1, Basic Tools. Cambridge University Press. . Commitment schemes are designed so that a party cannot change the value or statement after they have committed to it: that is, commitment schemes are ''binding''. Commitment schemes have important applications in a number of cryptographic protocols including secure coin flipping, zero-knowledge proofs, and secure computation. A way to visualize a commitment scheme is to think of a sender as putting a message in a locked box, and giving the box to a receiver. The message in the box is hidden from the receiver, who cannot open the lock themselves. Since the receiver has the box, the message inside cannot be changed—merely revealed if the sender chooses to give them the key ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitcoin
Bitcoin (abbreviation: BTC; Currency symbol, sign: ₿) is the first Decentralized application, decentralized cryptocurrency. Based on a free-market ideology, bitcoin was invented in 2008 when an unknown entity published a white paper under the pseudonym of Satoshi Nakamoto. Use of bitcoin as a currency began in 2009, with the release of its open-source software, open-source implementation. In 2021, Bitcoin in El Salvador, El Salvador adopted it as legal tender. It is mostly seen as an investment and has been described by some scholars as an economic bubble. As bitcoin is pseudonymous, Cryptocurrency and crime, its use by criminals has attracted the attention of regulators, leading to Legality of cryptocurrency by country or territory, its ban by several countries . Bitcoin works through the collaboration of computers, each of which acts as a Node (networking), node in the peer-to-peer bitcoin network. Each node maintains an independent copy of a public distributed ledger of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zerocoin
Zerocoin is a privacy protocol proposed in 2013 by Johns Hopkins University professor Matthew D. Green and his graduate students, Ian Miers and Christina Garman. It was designed as an extension to the Bitcoin protocol that would improve Bitcoin transactions' anonymity by having coin-mixing capabilities natively built into the protocol. Zerocoin is not currently compatible with Bitcoin. History Due to the public nature of the blockchain, users may have their privacy compromised while interacting with the network. To address this problem, third-party coin mixing service can be used to obscure the trail of cryptocurrency transactions. In May 2013, Matthew D. Green and his graduate students (Ian Miers and Christina Garman) proposed the Zerocoin protocol where cryptocurrency transactions can be anonymized without going through a trusted third-party, by which a coin is destroyed then minted again to erase its history. While a coin is spent, there is no information available which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hash Table
In computer science, a hash table is a data structure that implements an associative array, also called a dictionary or simply map; an associative array is an abstract data type that maps Unique key, keys to Value (computer science), values. A hash table uses a hash function to compute an ''index'', also called a ''hash code'', into an array of ''buckets'' or ''slots'', from which the desired value can be found. During lookup, the key is hashed and the resulting hash indicates where the corresponding value is stored. A map implemented by a hash table is called a hash map. Most hash table designs employ an Perfect hash function, imperfect hash function. Hash collision, Hash collisions, where the hash function generates the same index for more than one key, therefore typically must be accommodated in some way. In a well-dimensioned hash table, the average time complexity for each lookup is independent of the number of elements stored in the table. Many hash table designs also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Structure
In computer science, a data structure is a data organization and storage format that is usually chosen for Efficiency, efficient Data access, access to data. More precisely, a data structure is a collection of data values, the relationships among them, and the Function (computer programming), functions or Operator (computer programming), operations that can be applied to the data, i.e., it is an algebraic structure about data. Usage Data structures serve as the basis for abstract data types (ADT). The ADT defines the logical form of the data type. The data structure implements the physical form of the data type. Different types of data structures are suited to different kinds of applications, and some are highly specialized to specific tasks. For example, Relational database, relational databases commonly use B-tree indexes for data retrieval, while compiler Implementation, implementations usually use hash tables to look up Identifier (computer languages), identifiers. Data s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zero-knowledge Proof
In cryptography, a zero-knowledge proof (also known as a ZK proof or ZKP) is a protocol in which one party (the prover) can convince another party (the verifier) that some given statement is true, without conveying to the verifier any information ''beyond'' the mere fact of that statement's truth. The intuition underlying zero-knowledge proofs is that it is trivial to prove possession of the relevant information simply by revealing it; the hard part is to prove this possession without revealing this information (or any aspect of it whatsoever). In light of the fact that one should be able to generate a proof of some statement ''only'' when in possession of certain secret information connected to the statement, the verifier, even after having become convinced of the statement's truth, should nonetheless remain unable to prove the statement to further third parties. Zero-knowledge proofs can be interactive, meaning that the prover and verifier exchange messages according to some pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
