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This glossary is provided for your information only; it is not meant as a complete or authoritative description of the terms defined below or of the privacy and security ramifications of the technologies described.


The use of a password, certificate, personal identification number (PIN), or other information to validate an identity over a computer network.


A stored URL (web page address) that you can go to easily by clicking a bookmark icon in the Bookmarks Toolbar or choosing the bookmark's name from the Bookmarks menu.

Bookmarks Toolbar

The customizable toolbar that appears just below the Location Bar by default in Firefox. It contains buttons for your favorite bookmarks (or folders containing groups of bookmarks) that you can add or remove.


A computer program used to view the World Wide Web (commonly referred to as "the Internet"); also called a "web browser" or "Internet browser". Firefox is a browser. Other browsers include Google's Chrome, Apple's Safari, Microsoft's Internet Explorer, and Opera Software's Opera.


A collection of web page copies stored on your computer's hard disk or in its random-access memory (RAM). Firefox accumulates these copies as you browse the Web. When you click a link or type a URL to fetch a particular web page for which the cache already contains a copy, Firefox compares the cached copy to the original. If there have been no changes, Firefox uses the cached copy rather than re-fetching the original, saving processing and download time.


The digital equivalent of an ID card. A certificate specifies the name of an individual, company, or other entity and certifies that a public key, which is included in the certificate, belongs to that entity. When you digitally sign a message or other data, the digital signature for that message is created with the aid of the private key that corresponds to the public key in your certificate.


Software (such as an Internet browser) that sends requests to and receives information from a server, which is usually running on a different computer. A computer on which client software runs is also described as a client.

A small bit of information stored on your computer by some websites. When you visit such a site, the site asks Firefox to place one or more cookies on your hard disk. Later, when you return to the site, Firefox sends the site the cookies that belong to it. Cookies help websites keep track of information about you, such as the contents of your shopping cart. You can set your cookies options to control how cookies are used and how much information you are willing to let websites store on them.


The art and practice of scrambling (enciphering) and unscrambling (deciphering) information. For example, cryptographic techniques are used to scramble and unscramble information flowing between commercial websites and Firefox.


The process of unscrambling data that has been encrypted. See also encryption.

digital ID

See certificate.


The process of scrambling information in a way that disguises its meaning. For example, encrypted connections between computers make it very difficult for third-parties to unscramble, or decrypt, information flowing over the connection. Encrypted information can be decrypted only by someone who possesses the appropriate key.

Extensible Markup Language (XML)

An open standard for describing data. Unlike HTML, XML allows the developer of a web page to define special tags. For more information, see the online W3C document Extensible Markup Language (XML).


A XML web page that contains a list of links to other web pages. Special programs can read feeds to create a list of headlines from the links, automatically updating the list as it changes. News websites use feeds to quickly publish the latest headlines, and personal online journals often use feeds to quickly notify visitors about new entries. See also Live Bookmark.

File Transfer Protocol (FTP)

A standard that allows users to transfer files from one computer to another over a network. You can use Firefox to fetch files using FTP.


Federal Information Processing Standards Publications (FIPS PUBS) 140-1 is a US government standard for implementations of cryptographic modules — hardware or software that encrypts and decrypts data or performs other cryptographic operations (such as creating or verifying digital signatures). Many products sold to the US government must comply with one or more of the FIPS standards.

home page

The page Firefox is set to display every time you launch it or when you click the Home button. Also used to refer to the main page for a website from which you can explore the rest of the site.

Hypertext Markup Language (HTML)

The document format used for web pages. The HTML standard defines tags, or codes, used to define the text layout, fonts, style, images, and other elements that make up a web page.


A worldwide network of millions of computers that communicate with each other using standard protocols such as TCP/IP. Originally developed for the US military in 1969, the Internet grew to include educational and research institutions and, in the late 1990s, millions of businesses, organizations, and individuals. Today the Internet is used for email, browsing the World Wide Web, instant messaging, mailing lists and newsgroups, and many other purposes.

Internet protocol address (IP address)

The address of a computer on a TCP/IP network. Every computer on the Internet has an IP address. Clients have either a permanent IP address or one that is dynamically assigned to them each time they connect with the network.


A programming language developed by Sun Microsystems. A single Java program can run on many different platforms and operating systems, avoiding the need for programmers to create a separate version of each program for each platform/operating system. After Java is installed, Firefox can automatically download and run Java programs (also called applets).


A scripting language commonly used to construct web pages. Programmers use JavaScript to make web pages more interactive; JavaScript is often used to dynamically validate forms and select buttons. JavaScript can be used with Java, but it is technically a separate language. Java is not required for JavaScript to work correctly.

Live Bookmark

A special type of bookmark that acts as a folder to contain the links in a feed. You can create a Live Bookmark by visiting a site with a feed, clicking on the Live Bookmark icon in the Location Bar, and selecting the feed you wish to use.

Location Bar

The field (and associated buttons) near the top of a Firefox window where you can view and type in URLs. Also called the Awesome Bar or address bar.

master password

A password used to protect saved passwords and other private data. Firefox will prompt you for your master password when you wish to access this data. If you have multiple security devices, each security device will require a separate master password.

Navigation Toolbar

The toolbar near the top of the Firefox window that includes the Back and Forward buttons.

Password Manager

The part of Firefox that can help you remember some or all of your names and passwords by storing them on your computer's hard disk and entering them for you automatically when you visit such sites.

PKCS #11

The public-key cryptography standard that governs security devices such as smart cards.


Plugins add new capabilities to Firefox, such as the ability to play audio or video clips. Unlike other kinds of helper applications, a plugin typically can be opened within Firefox itself (internally). For example, an audio plugin lets you listen to audio files on a web page or in an e-mail message. Adobe Flash Player and Java are both examples of plugins.

private key

One of a pair of keys used in public-key cryptography. The private key is kept secret and is used to decrypt data that has been encrypted with the corresponding public key.


An intermediary or "go-between" program that acts as both a server and a client for the purpose of making requests on behalf of other clients.

search engine

A web-based program that allows users to search for and retrieve specific information from the World Wide Web. The search engine may search the full text of web documents or a list of keywords; it may also use librarians who review web documents and index them manually for retrieval. Typically, the user types a word or phrase into a search box, and the search engine displays links to relevant web pages.

secure connection

With a secure connection, the transfer of data between server and local browser is encrypted. Encryption can be made over various protocols (e.g. Secure Sockets Layer (SSL)) and with different encryption strength (e.g. 256 Bit, 1.024 Bit, etc.). Generally, the more bits the safer is the connection. See also encryption, secure site, cryptography.

secure site

A site that uses encryption in connections with Firefox to prevent other malicious Internet users from viewing transmitted data. When you visit secure sites, Firefox displays a lock icon in the Status Bar, and the icon in the Location Bar changes color. Firefox also displays the site's domain name in the Status Bar (to prevent malicious sites from stealing your data).

Secure Sockets Layer (SSL)

A protocol that allows mutual authentication between a client and a server for the purpose of establishing an authenticated and encrypted connection. SSL runs above TCP/IP and below HTTP, LDAP, IMAP, NNTP, and other high-level network protocols. The new Internet Engineering Task Force (IETF) standard called Transport Layer Security (TLS) is based on SSL. See also authentication, encryption.


Software (such as software that serves up web pages) that receives requests from and sends information to a client, which is usually running on a different computer. A computer on which server software runs is also described as a server.

Status Bar

The toolbar that appears at the bottom of the Firefox window. It shows icons for add-ons and other status indicators. The Status Bar has been replaced by the Add-on Bar in Firefox 4.


See Secure Sockets Layer (SSL).

Transmission Control Protocol/Internet Protocol (TCP/IP)

A Unix protocol used to connect computers running a variety of operating systems. TCP/IP is an essential Internet protocol and has become a global standard.

Uniform Resource Locator (URL)

The standardized address that tells Firefox how to locate a file or other resource on the Web (for example, Type URLs into Firefox's Location Bar to access web pages. URLs are also used in the links on web pages go to other web pages. Also known as an Internet or Web address.

web page

A single document on the World Wide Web that is specified by a unique address or URL. A web page may contain text, hyperlinks, and graphics.


A group of related web pages linked by hyperlinks and managed by a single company, organization, or individual. A website may include text, graphics, audio and video files, and links to other websites.

World Wide Web

Also known as the Web. A portion of the Internet that is made up of web pages stored by web servers and displayed by clients called web browsers (such as Firefox).

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