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Merkle Hash Tree
In cryptography and computer science, a hash tree or Merkle tree is a tree in which every "leaf" (node) is labelled with the cryptographic hash of a data block, and every node that is not a leaf (called a ''branch'', ''inner node'', or ''inode'') is labelled with the cryptographic hash of the labels of its child nodes. A hash tree allows efficient and secure verification of the contents of a large data structure. A hash tree is a generalization of a hash list and a hash chain. Demonstrating that a leaf node is a part of a given binary hash tree requires computing a number of hashes proportional to the logarithm of the number of leaf nodes in the tree. Conversely, in a hash list, the number is proportional to the number of leaf nodes itself. A Merkle tree is therefore an efficient example of a cryptographic commitment scheme, in which the root of the tree is seen as a commitment and leaf nodes may be revealed and proven to be part of the original commitment. The concept of a has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hash Tree
Hash, hashes, hash mark, or hashing may refer to: Substances * Hash (food), a coarse mixture of ingredients * Hash, a nickname for hashish, a cannabis product Hash mark *Hash mark (sports), a marking on hockey rinks and gridiron football fields * Hatch mark, a form of mathematical notation * Number sign (#), also known as the hash, hash mark, or (in American English) pound sign * Service stripe, a military and paramilitary decoration * Tally mark, a counting notation Computing * Hash function, an encoding of data into a small, fixed size; used in hash tables and cryptography * Hash table, a data structure using hash functions * Cryptographic hash function, a hash function used to authenticate message integrity * URI fragment, in computer hypertext, a string of characters that refers to a subordinate resource * Geohash, a spatial data structure which subdivides space into buckets of grid shape * Hashtag, a form of metadata often used on social networking websites * hash (Unix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Degradation
Data degradation is the gradual corruption of computer data due to an accumulation of non-critical failures in a data storage device. The phenomenon is also known as data decay, data rot or bit rot. Example Below are several digital images illustrating data degradation, all consisting of 326,272 bits. The original photo is displayed first. In the next image, a single bit was changed from 0 to 1. In the next two images, two and three bits were flipped. On Linux systems, the binary difference between files can be revealed using command (e.g. ). File:Bitrot in JPEG files, 0 bits flipped.jpg, 0 bits flipped File:Bitrot in JPEG files, 1 bit flipped.jpg, 1 bit flipped File:Bitrot in JPEG files, 2 bits flipped.jpg, 2 bits flipped File:Bitrot in JPEG files, 3 bits flipped.jpg, 3 bits flipped Primary storages Data degradation in dynamic random-access memory (DRAM) can occur when the electric charge of a bit in DRAM disperses, possibly altering program code or stored data. DRAM may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apache Cassandra
Cassandra is a free and open-source, distributed, wide-column store, NoSQL database management system designed to handle large amounts of data across many commodity servers, providing high availability with no single point of failure. Cassandra offers support for clusters spanning multiple datacenters, with asynchronous masterless replication allowing low latency operations for all clients. Cassandra was designed to implement a combination of Amazon's Dynamo distributed storage and replication techniques combined with Google's Bigtable data and storage engine model. History Avinash Lakshman, one of the authors of Amazon's Dynamo, and Prashant Malik initially developed Cassandra at Facebook to power the Facebook inbox search feature. Facebook released Cassandra as an open-source project on Google code in July 2008. In March 2009, it became an Apache Incubator project. On February 17, 2010, it graduated to a top-level project. Facebook developers named their database a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NoSQL
A NoSQL (originally referring to "non- SQL" or "non-relational") database provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases. Such databases have existed since the late 1960s, but the name "NoSQL" was only coined in the early 21st century, triggered by the needs of Web 2.0 companies. NoSQL databases are increasingly used in big data and real-time web applications. NoSQL systems are also sometimes called Not only SQL to emphasize that they may support SQL-like query languages or sit alongside SQL databases in polyglot-persistent architectures. Motivations for this approach include simplicity of design, simpler "horizontal" scaling to clusters of machines (which is a problem for relational databases), finer control over availability and limiting the object-relational impedance mismatch. The data structures used by NoSQL databases (e.g. key–value pair, wide column, graph, or docum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GNU Guix
GNU Guix () is a functional cross-platform package manager and a tool to instantiate and manage Unix-like operating systems, based on the Nix package manager. Configuration and package recipes are written in Guile Scheme. GNU Guix is the default package manager of the GNU Guix System distribution. Differing from traditional package managers, Guix (like Nix) utilizes a purely functional deployment model where software is installed into unique directories generated through cryptographic hashes. All dependencies for each software are included within each hash. This solves the problem of dependency hell, allows multiple versions of the same software to coexist and makes packages portable and reproducible. Performing scientific computations in a Guix setup has been proposed as a promising response to the replication crisis. The development of GNU Guix is intertwined with the GNU Guix System, an installable operating system distribution using the Linux-libre kernel and GN ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nix Package Manager
Nix is a cross-platform package manager that utilizes a purely functional deployment model where software is installed into unique directories generated through cryptographic hashes. It is also the name of the tool's programming language. A package's hash takes into account the dependencies, which is claimed to eliminate dependency hell, as an alternative to the typical solution of installing multiple versions of dependencies at the same time. This package management model advertises more reliable, reproducible, and portable packages. Nix packages are defined through a lazy functional programming language specifically designed for package management. Dependencies are tracked directly in this language through an intermediate format called "derivations". A Nix environment keeps track of references automatically, which allows unused packages to be garbage collected when no other package depends on them. At the cost of greater storage requirements, all upgrades in Nix are guaran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Certificate Transparency
Certificate Transparency (CT) is an Internet security standard for monitoring and auditing the issuance of digital certificates. The standard creates a system of public logs that seek to eventually record all certificates issued by publicly trusted certificate authorities, allowing efficient identification of mistakenly or maliciously issued certificates. Version 2.0 of the Certificate Transparency mechanism, the latest, is described in the experimental , which obsoletes the earlier version 1.0 described in . Technical overview The certificate transparency system consists of a system of append-only certificate logs. Logs are operated by many parties, including browser vendors and certificate authorities. Certificates that support certificate transparency must include one or more ''signed certificate timestamps'' (SCTs), which is a promise from a log operator to include the certificate in their log within a ''maximum merge delay'' (MMD). At some point within the maximum merge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethereum
Ethereum is a decentralized, open-source blockchain with smart contract functionality. Ether (Abbreviation: ETH; sign: Ξ) is the native cryptocurrency of the platform. Among cryptocurrencies, ether is second only to bitcoin in market capitalization. Ethereum was conceived in 2013 by programmer Vitalik Buterin. Additional founders of Ethereum included Gavin Wood, Charles Hoskinson, Anthony Di Iorio and Joseph Lubin. In 2014, development work began and was crowdfunded, and the network went live on 30 July 2015. Ethereum allows anyone to deploy permanent and immutable decentralized applications onto it, with which users can interact. Decentralized finance (DeFi) applications provide a broad array of financial services without the need for typical financial intermediaries like brokerages, exchanges, or banks, such as allowing cryptocurrency users to borrow against their holdings or lend them out for interest. Ethereum also allows users to create and exchange NFTs, whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bitcoin
Bitcoin (abbreviation: BTC; sign: ₿) is a decentralized digital currency that can be transferred on the peer-to-peer bitcoin network. Bitcoin transactions are verified by network nodes through cryptography and recorded in a public distributed ledger called a blockchain. The cryptocurrency was invented in 2008 by an unknown person or group of people using the name Satoshi Nakamoto. The currency began use in 2009, when its implementation was released as open-source software. The word "''bitcoin''" was defined in a white paper published on October 31, 2008. It is a compound of the words ''bit'' and ''coin''. The legality of bitcoin varies by region. Nine countries have fully banned bitcoin use, while a further fifteen have implicitly banned it. A few governments have used bitcoin in some capacity. El Salvador has adopted Bitcoin as legal tender, although use by merchants remains low. Ukraine has accepted cryptocurrency donations to fund the resistance to the 2022 Rus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeronet
ZeroNet is a decentralized web-like network of peer-to-peer users, created by Tamas Kocsis in 2015, programming for the network was based in Budapest, Hungary; is built in Python; and is fully open source. Instead of having an IP address, sites are identified by a public key (specifically a bitcoin address). The private key allows the owner of a site to sign and publish changes, which propagate through the network. Sites can be accessed through an ordinary web browser when using the ZeroNet application, which acts as a local webhost for such pages. In addition to using bitcoin cryptography, ZeroNet uses trackers from the BitTorrent network to negotiate connections between peers. ZeroNet is not anonymous by default, but it supports routing traffic through the Tor network. The ZeroNet website and bittorrent tracker are blocked in mainland China. Despite the censorship, however, it's still possible to access ZeroNet from behind the Great Firewall of China, even over Tor, by boo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tahoe-LAFS
Tahoe-LAFS (Tahoe Least-Authority File Store) is a free and open, secure, decentralized, fault-tolerant, distributed data store and distributed file system. It can be used as an online backup system, or to serve as a file or Web host similar to Freenet, depending on the front-end used to insert and access files in the Tahoe system. Tahoe can also be used in a RAID-like fashion using multiple disks to make a single large Redundant Array of Inexpensive Nodes (RAIN) pool of reliable data storage. The system is designed and implemented around the " principle of least authority" (POLA), described by Brian Warner (one of the project's original founders) as the idea "that any component of the system should have as little power of authority as it needs to get its job done". Strict adherence to this convention is enabled by the use of cryptographic capabilities that provide the minimum set of privileges necessary to perform a given task by asking agents. A RAIN array acts as a storage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercurial
Mercurial is a distributed revision control tool for software developers. It is supported on Microsoft Windows and Unix-like systems, such as FreeBSD, macOS, and Linux. Mercurial's major design goals include high performance and scalability, decentralization, fully distributed collaborative development, robust handling of both plain text and binary files, and advanced branching and merging capabilities, while remaining conceptually simple. It includes an integrated web-interface. Mercurial has also taken steps to ease the transition for users of other version control systems, particularly Subversion. Mercurial is primarily a command-line driven program, but graphical user interface extensions are available, e.g. TortoiseHg, and several IDEs offer support for version control with Mercurial. All of Mercurial's operations are invoked as arguments to its driver program hg (a reference to Hg – the chemical symbol of the element mercury). Olivia Mackall originated Mercurial and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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