OATH : → Initiative for Open Authentication
OAuth : → Open Authorization
Obfuscation : The deliberate act of creating source or machine code that is difficult for humans to understand. Like obfuscation in natural language, it may use needlessly roundabout expressions to compose statements. Programmers may deliberately obfuscate code to conceal its purpose or its logic or implicit values embedded in it (security through obscurity), primarily in order to prevent tampering, deter reverse engineering, or even as a puzzle or recreational challenge for someone reading the source code. †
Object : A variable, data structure, function, or method, and as such, a value in memory referenced by an identifier. In the class-based object-oriented programming paradigm, an object refers to a particular instance of a class, where the object can be a combination of variables, functions, and data structures. In relational database management, an object can be a table or column, or an association between data and a database entity (such as relating a person’s age to a specific person). †
Object-Oriented CSS : A CSS methodology. The focus of OOCSS is the idea of treating page elements as objects, giving all these objects classes, and regarding objects’ classes as single entities in style sheets. OOCSS was presented in 2009 by Nicole Sullivan. †
Object-Oriented Programming : A programming paradigm based on the concept of “objects,” which can contain data, in the form of fields (often known as attributes or properties), and code, in the form of procedures (often known as methods). A feature of objects is their procedures that can access and often modify the data fields of the object with which they are associated (objects have a notion of “this” or “self”). In OOP, computer programs are designed by making them out of objects that interact with one another. OOP languages are diverse, but the most popular ones are class-based, meaning that objects are instances of classes, which also determine their types. †
Objectives and Key Results : A framework for defining and tracking objectives and their outcomes. OKR comprise an objective—a clearly defined goal—and one or more key results—specific measures used to track the achievement of that goal. The goal of OKR is to define how to achieve objectives through concrete, specific, and measurable actions. Key results can be measured on a 0–100% scale or any numerical unit. The development of OKR is generally attributed to Andy Grove, who introduced the approach to Intel and documented OKR in his 1983 book High Output Management. †
Observer : → Navigator
Observer pattern : A software design pattern in which an object, called the subject, maintains a list of its dependents, called observers, and notifies them automatically of any state changes, usually by calling one of their methods. The observer pattern is mainly used to implement distributed event handling systems. †
OCP : → Open-Closed Principle
OCSP : → Online Certificate Status Protocol
OCSP stapling : A standard for checking the revocation status of X.509 digital certificates. OCSP stapling allows the presenter of a certificate to bear the resource cost involved in providing Online Certificate Status Protocol (OCSP) responses by appending (“stapling”) a time-stamped OCSP response signed by the CA to the initial TLS handshake, eliminating the need for clients to contact the CA, with the aim of improving both security and performance. †
Offline : Not being connected to the Internet.
Offline First : The idea of not assuming permanent, fast Internet connectivity, and developing sites and apps so as to also work with no or poor connectivity. ℹ︎ offlinefirst.org
OGP : → Open Graph Protocol
OIDC : → OpenID Connect
OKR : → Objectives and Key Results
OLAP : → Online Analytical Processing
OLTP : → Online Transaction Processing
One-based indexing : The indexing of the first element of an array by subscript of 1. †
One-Time Password : A password that is valid for only one login session or transaction, on a computer system or other digital device. OTPs avoid a number of shortcomings that are associated with traditional (static) password-based authentication; a number of implementations also incorporate two-factor authentication by ensuring that the one-time password requires access to something a person has (such as a small keyring fob device with the OTP calculator built into it, or a smartphone with an OTP app) as well as something a person knows (such as a PIN). The most important advantage that is addressed by OTPs is that, in contrast to static passwords, they are not vulnerable to replay attacks. †
Online Analytical Processing : An approach to answer multi-dimensional analytical (MDA) queries swiftly in computing. OLAP is part of the broader category of business intelligence, which also encompasses relational databases, report writing, and data mining. †
Online Certificate Status Protocol : An Internet protocol used for obtaining the revocation status of an X.509 digital certificate. OCSP is described in RFC 6960 and is on the Internet standards track. It was created as an alternative to certificate revocation lists (CRL). Some web browsers use OCSP to validate HTTPS certificates. †
Online Transaction Processing : The facilitating and managing of transaction-oriented applications by information systems. The term “transaction” can have two meanings, both of which might apply: In the realm of computers or database transactions it denotes an atomic change of state, whereas in the realm of business or finance, the term typically denotes an exchange of economic entities. OLTP may use transactions of the first type to record transactions of the second. †
OOCSS : → Object-Oriented CSS
OOM : → Out of memory
OOP : → Object-Oriented Programming
OOPIF : → Out-of-Process Iframe
Open Authorization : An open standard for access delegation, commonly used as a way for Internet users to grant websites or applications access to their information on other websites but without giving them the passwords. This mechanism is used by companies such as Amazon, Google, Facebook, Microsoft, and Twitter to permit the users to share information about their accounts with third-party services. OAuth is a service that is complementary to and distinct from OpenID; however, OAuth is directly related to OpenID Connect (OIDC), since OIDC is an authentication layer built on top of OAuth 2.0. Development of OAuth began in 2006. † ℹ︎ oauth.net
Open Graph : → Open Graph Protocol
Open Graph Protocol : A microformat that enables developers to integrate their pages into Facebook’s Social Graph, a global mapping and tracking tool. The respective pages gain the functionality of other graph objects including profile links and stream updates for connected users. OGP was created in 2010 by Facebook. † ℹ︎ ogp.me
Open Source : Products that include permission to use the source code, design documents, or content of the product. Open Source most commonly refers to the open source model, in which software or other products are released under a permissive open source license. Use of the term originated with software, but has expanded beyond the software sector to cover other open content and forms of open collaboration. † ℹ︎ opensource.org
Open Systems Interconnection model : → OSI model
Open Web Application Security Project : An online community that produces freely-available articles, methodologies, documentation, tools, and technologies in the field of web application security. OWASP was founded in 2001. † ℹ︎ owasp.org
Open-Closed Principle : The idea that “software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification,” that is, that such an entity can allow its behavior to be extended without modifying its source code. †
OpenID : An open standard and decentralized authentication protocol. Promoted by the non-profit OpenID Foundation, OpenID allows users to be authenticated by cooperating sites (known as relying parties, or RP) using a third-party service, eliminating the need for webmasters to provide their own ad hoc login systems, and allowing users to log into multiple unrelated websites without having to have a separate identity and password for each. Users create accounts by selecting an OpenID identity provider and then use those accounts to sign onto any website that accepts OpenID authentication. † ℹ︎ openid.net
OpenID Connect : An authentication layer on top of the OAuth 2.0 authorization framework. OIDC allows computing clients to verify the identity of an end user based on the authentication performed by an authorization server, as well as to obtain the basic profile information about the end user in an interoperable and REST-like manner. † ℹ︎ openid.net/connect
OpenType : A format for scalable computer fonts. OpenType was built on its predecessor TrueType, retaining TrueType’s basic structure and adding many intricate data structures for prescribing typographic behavior. The specification was developed at Microsoft, with Adobe Systems contributing by the time of public announcement in 1996. †
Opera : A cross-platform web browser. Opera was first released in 1995. ℹ︎ opera.com
Opera Mini : A mobile web browser developed by Opera. It was primarily designed for the Java ME platform, as a low-end sibling for Opera Mobile. Opera Mini was previously developed for iOS, Windows 10 Mobile, Windows Phone 8.1, BlackBerry, Symbian, and Bada. As of 2022, the Android build is the only version still under active development. Opera Mini requests web pages through Opera’s compression servers, which process and compress requested web pages before sending them to the mobile phone. † ℹ︎ opera.com/mobile/mini
Operand : In mathematics, the object of a mathematical operation, i.e., the object or quantity that is operated on. In “3 + 6”, “3” and “6” are operands, while “+” is an (addition) operator. †
Operating System : System software that manages computer hardware and software resources and that provides services for computer programs. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although application code is usually executed directly by the hardware and frequently makes system calls to an OS function, or is interrupted by it. Operating systems are found on many devices that contain a computer—from cellular phones and video game consoles to web servers and supercomputers. †
Operator
: In mathematics, a mapping that acts on elements of a space to produce elements of another space (possibly the same space, sometimes required to be the same space). An operator is also used for denoting the symbol of a mathematical operation, which is related with the meaning of “operator” in computer programming. †
: In programming, constructs which behave generally like functions, but which differ syntactically or semantically from usual functions. Common simple examples include arithmetic (addition with +), comparison (with >), and logical operations (such as AND or &&). More involved examples include assignment (usually = or :=), field access in a record or object (usually .), and the scope resolution operator (often ::). Languages usually define a set of built-in operators, and in some cases allow users to add new meanings to existing operators or even define completely new operators. †
Optimization : The selection of a best element (with regard to some criterion) from some set of available alternatives. Optimization problems of sorts arise in all quantitative disciplines from computer science and engineering to operations research and economics, and the development of solution methods has been of interest in mathematics for centuries. In the simplest case, an optimization problem consists of maximizing or minimizing a real function by systematically choosing input values from within an allowed set and computing the value of the function. Casually, optimization refers to improving a product, service, or software. †
Optional markup : Markup (like HTML code and particular tags, attributes, and quotes) that is not necessary for a document to be functional and valid.
Orca : An extensible screen reader from the GNOME project for individuals who are blind or visually impaired. Using various combinations of speech synthesis and braille, Orca helps provide access to applications and toolkits that support the AT-SPI. The name Orca, which is the name of a killer whale, is a nod to the long-standing tradition of naming screen readers after aquatic creatures. † ℹ︎ wiki.gnome.org/Projects/Orca
Origin : A concept defined by the scheme (protocol), host (domain), and port of the URL used to access it. Two objects have the same origin only when the scheme, host, and port all match. Some operations are restricted to same-origin content, and this restriction can be lifted using cross-origin resource sharing (CORS). ‡
Origin trials : An approach to enable manageable experimentation with web platform features involving explicit developer opt-in, feature trial validation, and feedback collection. ℹ︎ is.gd/6gJDY4
Orphan : A paragraph-opening line that appears by itself at the bottom of a page or column, separated from the rest of the text. †
Orthogonality : A software design principle meaning that change of one piece of software does not affect other pieces, or that operations do not have side effects. Orthogonality in a programming language means that a relatively small set of primitive constructs can be combined in a relatively small number of ways to build the control and data structures of the language. It is associated with simplicity; the more orthogonal the design, the fewer exceptions. This makes it easier to learn, read and write programs in a programming language. The meaning of an orthogonal feature is independent of context; the key parameters are symmetry and consistency (for example, a pointer is an orthogonal concept). †
OS : → Operating System
OSI model : A conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard communication protocols. The model partitions a communication system into abstraction layers. The original version of the model had seven layers, namely the physical, data link, network, transport, session, presentation, and application layers. The OSI model was first defined in 1978. †
OTA : → Over the Air
OTF : → OpenType
OTP : → One-Time Password
Out of memory : An often undesired state of computer operation where no additional memory can be allocated for use by programs or the operating system. Such a system will be unable to load any additional programs, and since many programs may load additional data into memory during execution, these will cease to function correctly. †
Out-of-Process Iframe : An iframe that’s being handled in a different rendering process for security reasons.
Outline
: A CSS feature managed with special outline properties that allows to draw lines around elements. A CSS outline is different from a border in that it does not take up space, and that it may be non-rectangular.
Over the Air : Various methods of distributing new software, configuration settings, and even encryption keys to devices like mobile phones, set-top boxes, or secure voice communication equipment (encrypted 2-way radios). One important feature of OTA is that one central location can send an update to all the users and that the update applies immediately to everyone on the channel. †
OWASP : → Open Web Application Security Project
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