Glossary

Tech Terms | Abbreviations A–Z

P


PFS   PGP   PHP   Podcast   Portable App   Pretty URL


PFS

(Abbr.): Perfect Forward Secrecy. In cryptography, forward secrecy (FS), also known as perfect forward secrecy (PFS), is a feature of specific key agreement protocols that gives assurances that session keys will not be compromised even if long-term secrets used in the session key exchange are compromised. For HTTPS the long-term secret is typically the private signing key of the server. Forward secrecy protects past sessions against future compromises of keys or passwords. By generating a unique session key for every session a user initiates, the compromise of a single session key will not affect any data other than that exchanged in the specific session protected by that particular key. This by itself is not sufficient for forward secrecy which additionally requires that a long-term secret compromise does not affect the security of past session keys.

Forward secrecy protects data on the transport layer of a network that uses common SSL/TLS protocols, including OpenSSL, when its long-term secret keys are compromised, as with the Heartbleed security bug. If forward secrecy is used, encrypted communications and sessions recorded in the past cannot be retrieved and decrypted should long-term secret keys or passwords be compromised in the future, even if the adversary actively interfered, for example via a man-in-the-middle attack.

The value of forward secrecy is that it protects past communication. This reduces the motivation for attackers to compromise keys. For instance, if an attacker learns a long-term key, but the compromise is detected and the long-term key is revoked and updated, relatively little information is leaked in a forward secure system.

The value of forward secrecy depends on the assumed capabilities of an adversary. Forward secrecy has value if an adversary is assumed to be able to obtain secret keys from a device (read access) but is either detected or unable to modify the way session keys are generated in the device (full compromise). In some cases an adversary who can read long-term keys from a device may also be able to modify the functioning of the session key generator, as in the backdoored Dual Elliptic Curve Deterministic Random Bit Generator. If an adversay can make the random number generator predictable past traffic will be protected but all future traffic will be compromised.

The value of forward secrecy is limited not only by the assumption that an adversary will attack a server by only stealing keys and not modifying the random number generator used by the server but it is also limited by the assumption that the adversary will only passively collect traffic on the communications link and not be active using a Man-in-the-Middle (MITM) attack. Forward secrecy typically uses an ephemeral Diffie-Hellman key exchange to prevent reading past traffic. The ephemeral Diffie-Hellman key exchange is often signed by the server using a static signing key. If an adversary can steal (or obtain through a court order) this static (long term) signing key, the adverary can masqerade as the server to the client and as the client to the server and implement a classic Man-in-the-Middle attack.

This article is based on the article Forward_secrecy from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

Pretty Good Privacy (PGP)

is an encryption program that provides cryptographic privacy and authentication for data communication. PGP is used for signing, encrypting, and decrypting texts, e-mails, files, directories, and whole disk partitions and to increase the security of e-mail communications. Phil Zimmermann developed PGP in 1991.

PGP and similar software follow the OpenPGP, an open standard of PGP encryption software, standard (RFC 4880) for encrypting and decrypting data.

This article is based on the article Pretty_Good_Privacy from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

PHP

PHP is a general-purpose scripting language especially suited to web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1994. The PHP reference implementation is now produced by The PHP Group. PHP originally stood for Personal Home Page, but it now stands for the recursive initialism PHP: Hypertext Preprocessor.

PHP code is usually processed on a web server by a PHP interpreter implemented as a module, a daemon or as a Common Gateway Interface (CGI) executable. On a web server, the result of the interpreted and executed PHP code – which may be any type of data, such as generated HTML or binary image data – would form the whole or part of an HTTP response. Various web template systems, web content management systems, and web frameworks exist which can be employed to orchestrate or facilitate the generation of that response. Additionally, PHP can be used for many programming tasks outside of the web context, such as standalone graphical applications and robotic drone control. PHP code can also be directly executed from the command line.

The standard PHP interpreter, powered by the Zend Engine, is free software released under the PHP License. PHP has been widely ported and can be deployed on most web servers on almost every operating system and platform, free of charge.

The PHP language evolved without a written formal specification or standard until 2014, with the original implementation acting as the de facto standard which other implementations aimed to follow. Since 2014, work has gone on to create a formal PHP specification.

W3Techs reports that, as of April 2021, "PHP is used by 79.2% of all the websites whose server-side programming language we know."

This article is based on the article PHP from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

Podcast

podcast is a program made available in digital format for download over the Internet. For example, an episodic series of digital audio files that a user can download to a personal device to listen to at a time of their choosing. Podcasts are primarily an audio medium, with some programs offering a supplemental video component. Streaming applications and podcasting services provide a convenient and integrated way to manage a personal consumption queue across many podcast sources and playback devices. There are also podcast search engines, which help users find and share podcast episodes.

A podcast series usually features one or more recurring hosts engaged in a discussion about a particular topic or current event. Discussion and content within a podcast can range from carefully scripted to completely improvised. Podcasts combine elaborate and artistic sound production with thematic concerns ranging from scientific research to slice-of-life journalism. Many podcast series provide an associated website with links and show notes, guest biographies, transcripts, additional resources, commentary, and occasionally a community forum dedicated to discussing the show's content.

The cost to the consumer is low, and many podcasts are free to download. Some podcasts are underwritten by corporations or sponsored, with the inclusion of commercial advertisements. In other cases, a podcast could be a business venture supported by some combination of a paid subscription model, advertising or product delivered after sale. Because podcast content is often free, podcasting is often classified as a disruptive medium, adverse to the maintenance of traditional revenue models

Podcasting is the preparation and distribution of audio files using RSS feeds to the devices of subscribed users. A podcaster normally buys this service from a podcast hosting company like SoundCloud or Libsyn. Hosting companies then distribute these audio files to streaming services, such as Apple and Spotify, which users can listen to on their smartphones or digital music and multimedia players, like an iPhone. 

As of December 2022, there are at least 2,999,008 podcasts and 152,596,784 episodes.

This article is based on the article Podcast from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

Portable App

A portable application(portable app), sometimes also calledstandalone, is aprogramdesigned to read and write its configuration settings into an accessible folder in the computer, usually in the folder where the portable application can be found. This makes it easier to transfer the program with the user's preferences and data between different computers. A program that doesn't have any configuration options can also be a portable application.

Portable applications can be stored on anydata storage device, including internalmass storage, afile share,cloud storageor external storage such asUSB drivesandfloppy disks—storing its program files and any configuration information and data on the storage medium alone. If no configuration information is required a portable program can be run fromread-onlystorage such asCD-ROMsandDVD-ROMs. Some applications are available in bothinstallableand portable versions.

Some applications which are not portable by default do support optional portability through other mechanisms, the most common beingcommand-line arguments. Examples might include/portableto simply instruct the program to behave as a portable program, or--cfg=/path/inifileto specify the configuration file location.

Like any application, portable applications must be compatible with the computer system hardware andoperating system.

Depending on the operating system,portabilityis more or less complex to implement; to operating systems such asAmigaOS, all applications are by definition portable.

This article is based on the article Portable_application from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

Pretty URL

Also sometimes referred to as Clean URLs, RESTful URLs, user-friendly URLs, or search engine-friendly URLs, are Uniform Resource Locators (URLs) intended to improve the usability and accessibility of a website or web service by being immediately and intuitively meaningful to non-expert users. Such URL schemes tend to reflect the conceptual structure of a collection of information and decouple the user interface from a server's internal representation of information. Other reasons for using clean URLs include search engine optimization (SEO), conforming to the representational state transfer (REST) style of software architecture, and ensuring that individual web resources remain consistently at the same URL. This makes the World Wide Web a more stable and useful system, and allows more durable and reliable bookmarking of web resources.

Pretty URLs also do not contain implementation details of the underlying web application. This carries the benefit of reducing the difficulty of changing the implementation of the resource at a later date. For example, many URLs include the filename of a server-side script, such as example.php, example.asp or cgi-bin. If the underlying implementation of a resource is changed, such URLs would need to change along with it. Likewise, when URLs are not "clean", if the site database is moved or restructured it has the potential to cause broken links, both internally and from external sites, the latter of which can lead to removal from search engine listings. The use of clean URLs presents a consistent location for resources to user-agents regardless of internal structure. A further potential benefit to the use of clean URLs is that the concealment of internal server or application information can improve the security of a system.

Eh? What? Didn't you get it? Here again in simple language:
My personal short explanation for Pretty URL: easy-to-remember web address as “talking name” like these:

This article is based on the article Clean_URL from the free encyclopedia Wikipedia and is licensed under Creative Commons CC-BY-SA 3.0 Unported (short version). A list of authors is available in Wikipedia.

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Keyword list: Client, Computer, Database, Details, Download, E-Mail, Glossary, HTML, HTTP, HTTPS, Hardware, Help, Hypertext, IT, Internet, Link, Links, Network, P, PFS, PGP, PHP, Pretty URL, Privacy, SSL, Search Engine, Server, Service, Services, Software, Storage, TLS, Tests, Tips, URL, User, Website, Who, World Wide Web, iPhone

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