%brandDTD; ]> Glossary
This glossary is provided for your information only, and is not meant to be relied upon as a complete or authoritative description of the terms defined below or of the privacy and/or security ramifications of the technologies described.


A piece of software that can be added to &brandShortName; to change its appearance, behavior, or to add new features. It can also change the language shown in the user interface. See also extension, language pack, plugin, and theme.
The use of a password, certificate, personal identification number (PIN), or other information to validate an identity over a computer network. See also password-based authentication, certificate-based authentication, client authentication, server authentication.
A stored web page address (URL) that you can go to easily by clicking a bookmark icon in the Personal Toolbar or choosing the bookmark's name from the Bookmarks menu.
See certificate authority (CA)
CA certificate
A certificate that identifies a certificate authority. See also certificate authority (CA), subordinate CA, root CA.
A collection of web page copies stored on your computer's hard disk or in its random-access memory (RAM). The browser 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, the browser compares the cached copy to the original. If there have been no changes, the browser uses the cached copy rather than refetching the original, saving processing and download time.
caret browsing
A &brandShortName; feature that allows you to navigate through text in Web pages and e-mail messages (or this Help window) with a caret. Using your keyboard, you can navigate and select text like you do in a text editor. You can turn caret browsing mode on or off by pressing the F7 key. Caret browsing mode can also be enabled or disabled in Advanced Preferences - Keyboard Navigation.
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. A certificate is issued and digitally signed by a certificate authority (CA). A certificate's validity can be verified by checking the CA's digital signature. Also called digital ID, digital passport, public-key certificate, X.509 certificate, and security certificate. See also public-key cryptography.
certificate authority (CA)
A service that issues a certificate after verifying the identity of the person or entity the certificate is intended to identify. A CA also renews and revokes certificates and generates a list of revoked certificates at regular intervals. CAs can be independent vendors or a person or organization using certificate-issuing server software (such as &brandShortName; Certificate Management System). See also certificate, CRL (certificate revocation list).
certificate backup password
A password that protects a certificate that you are backing up or have previously backed up. Certificate Manager asks you to set this password when you back up a certificate, and requests it when you attempt to restore a certificate that has previously been backed up.
certificate-based authentication
Verification of identity based on certificates and public-key cryptography. See also password-based authentication.
certificate chain
A hierarchical series of certificates signed by successive certificate authorities. A CA certificate identifies a certificate authority (CA) and is used to sign certificates issued by that authority. A CA certificate can in turn be signed by the CA certificate of a parent CA and so on up to a root CA.
certificate fingerprint
A unique number associated with a certificate. The number is not part of the certificate itself but is produced by applying a mathematical function to the contents of the certificate. If the contents of the certificate change, even by a single character, the function produces a different number. Certificate fingerprints can therefore be used to verify that certificates have not been tampered with.
Certificate Manager
The part of the browser that allows you to view and manage certificates. To view the main Certificate Manager window: Open the &brandShortName; Edit menu, choose Preferences, click Privacy and Security, and then click Manage Certificates.
certificate renewal
The process of renewing a certificate that is about to expire.
certificate verification
When Certificate Manager verifies a certificate, it confirms that the digital signature was created by a CA whose own CA certificate is both on file with Certificate Manager and marked as trusted for issuing that kind of certificate. It also confirms that the certificate being verified has not itself been marked as untrusted. Finally, if the OCSP (Online Certificate Status Protocol) has been activated, Certificate Manager also performs an online check. It does so by looking up the certificate in a list of valid certificates maintained at a URL that is specified either in the certificate itself or in the browser's Validation preferences. If any of these checks fail, Certificate Manager marks the certificate as unverified and won't recognize the identity it certifies.
See cryptographic algorithm.
Software (such as browser software) 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.
client authentication
The process of identifying a client to a server, for example with a name and password or with a client SSL certificate and some digitally signed data. See also SSL (Secure Sockets Layer), server authentication.
client SSL certificate
A certificate that a client (such as browser software) presents to a server to authenticate the identity of the client (or the identity of the person using the client) using the SSL (Secure Sockets Layer) protocol. See also client authentication.
Component Bar
The toolbar located at the bottom left of any &brandShortName; window. The Component Bar allows you to switch between &brandShortName; components by clicking icons for Browser, Mail & Newsgroups, Composer, and so on.
A small bit of information stored on your computer by some websites. When you visit such a website, the website asks your browser to place one or more cookies on your hard disk. Later, when you return to the website, your browser sends the website 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 cookie preferences to control how cookies are used and how much information you are willing to let websites store on them. See also foreign cookie.
The part of the browser that you can use to control cookies.
CRL (certificate revocation list)
A list of revoked certificates that is generated and signed by a certificate authority (CA). You can download the latest CRL to your browser or to a server, then check against it to make sure that certificates are still valid before permitting their use for authentication.
cryptographic algorithm
A set of rules or directions used to perform cryptographic operations such as encryption and decryption. Sometimes called a cipher.
The art and practice of scrambling (encrypting) and unscrambling (decrypting) information. For example, cryptographic techniques are used to scramble an unscramble information flowing between commercial websites and your browser. See also public-key cryptography.
The process of unscrambling data that has been encrypted. See also encryption.
digital ID
See certificate.
digital signature
A code created from both the data to be signed and the private key of the signer. This code is unique for each new piece of data. Even a single comma added to a message changes the digital signature for that message. Successful validation of your digital signature by appropriate software not only provides evidence that you approved the transaction or message, but also provides evidence that the data has not changed since you digitally signed it. A digital signature has nothing to do with a handwritten signature, although it can sometimes be used for similar legal purposes. See also nonrepudiation, tamper detection.
distinguished name (DN)
A specially formatted name that uniquely identifies the subject of a certificate.
dual key pairs
Two public-private key pairs—four keys altogether—corresponding to two separate certificates. The private key of one pair is used for signing operations, and the public and private keys of the other pair are used for encryption and decryption operations. Each pair corresponds to a separate certificate. See also public-key cryptography.
Surreptitious interception of information sent over a network by an entity for which the information is not intended.
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. See also public-key cryptography.
encryption certificate
A certificate whose public key is used for encryption only. Encryption certificates are not used for signing operations. See also dual key pairs, signing certificate.
encryption key
A private key used for encryption only. An encryption key and its equivalent private key, plus a signing key and its equivalent public key, constitute a dual key pairs.
A type of add-on that changes the behavior of &brandShortName; or adds new features to it.
A frequently updated source of references to web pages, usually blog articles or news. Technically it is an XML document available through a public well-known URL, comprising of several items inside, each one containing some metadata (possibly including a summary) and an URL to the full blog or news article. The XML document is regenerated at fixed intervals, or whenever a new article is published to the website. Web applications can subscribe to the URL serving the feed and present the new articles as they are updated in the underlying XML document. There are specific XML formats for feeds, most common of which are RSS and Atom.
See certificate fingerprint.
Federal Information Processing Standards Publications (FIPS PUBS) 140-1 is a US government standard for implementations of cryptographic modules—that is, 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.
A cookie from one website that gets stored on your computer when you visit a different website. Sometimes a website displays content that is hosted on another website. That content can be anything from an image to text or an advertisement. The second website that hosts such elements also has the ability to store a cookie in your browser, even though you don't visit it directly. Also known as third-party cookie.
Frames are web pages contained inside of an all-encompasssing meta page.
FTP (File Transfer Protocol)
A standard that allows users to transfer files from one computer to another over a network. You can use your browser to fetch files using FTP.
helper application
Any application that is used to open or view a file downloaded by the browser. A plugin is a special kind of helper application that installs itself into the Plugins directory of the main browser installation directory and can typically be opened within the browser itself (internally). Microsoft Word, Adobe Photoshop, and other external applications are considered helper applications but not plugins, since they don't install themselves into the browser directory, but can be opened from the download dialog box.
home page
The page your browser 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 website.
HTML (HyperText Markup Language)
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.
HTTP (HyperText Transfer Protocol)
The protocol used to transfer web pages (HyperText documents) between browsers and servers over the World Wide Web.
HTTPS (HyperText Transfer Protocol Secure)
The secure version of the HTTP protocol that uses SSL to ensure the privacy of customer data (such as credit card information) while en route over the Internet.
IMAP (Internet Message Access Protocol)
A standard mail server protocol that allows you to store all your messages and any changes to them on the server rather than on your computer's hard disk. Using IMAP rather than POP saves disk space and allows you to access your entire mailbox, including sent mail, drafts, and custom folders, from any location. Using an IMAP server over a modem is generally faster than using a POP mail server, since you initially download message headers only. Not all ISPs support IMAP.
Also known as implied or opt-out consent. Used to describe privacy settings that may allow websites to gather information about you (for example by means of cookies and online forms) unless you explicitly choose to withhold your consent by selecting an option on a page that the website provides for that purpose. Your consent may not be requested when the information is actually gathered.
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 (WWW), instant messaging, usegroups, and many other purposes.
IP address (Internet protocol 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. IP addresses are written as four sets of numbers, like this:
IRC (Internet Relay Chat)
A protocol used to chat with other people in real-time using an IRC client.
ISP (Internet Service Provider)
A company/institution that provides Internet connections.
A programming language developed by Sun Microsystems. A single Java program can run on many different kinds of computers, thus avoiding the need for programmers to create a separate version of each program for each kind of computer. Your browser 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; for example, to display forms and buttons. JavaScript can be used with Java, but is technically a separate language. Java is not required for JavaScript to work correctly.
A large number used by a cryptographic algorithm to encrypt or decrypt data. A person's public key, for example, allows other people to encrypt messages to that person. The encrypted messages must be decrypted with the corresponding private key. See also public-key cryptography.
language pack
A type of add-on that adds a new language to the user interface of &brandShortName;.
LDAP (Lightweight Directory Access Protocol)
A standard protocol for accessing directory services, such as corporate address books, across multiple platforms. You can set up your browser to access LDAP directories from the Address Book. You can also set up Mail & Newsgroups to use an LDAP directory for email address autocompletion.
Location Bar
The field (and associated buttons) near the top of a browser window where you can type a URL or search terms.
master key
A symmetric key used by Certificate Manager to encrypt information. For example, Password Manager uses Certificate Manager and your master key to encrypt email passwords, website passwords, and other stored sensitive information. See also symmetric encryption.
master password
A password used by Certificate Manager to protect the master key and/or private keys stored on a security device. Certificate Manager needs to access your private keys, for example, when you sign email messages or use one of your own certificates to identify yourself to a website. It needs to access your master key when Password Manager or Form Manager reads or adds to your personal information. You can set or change your master password from the Master Passwords preferences panel. Each security device requires a separate master password. See also private key, master key.
Presentation of an entity as a person or organization that it is not. For example, a website might pretend to be a furniture store when it is really just a website that takes credit card payments but never sends any goods. See also spoofing.
The toolbar near the top of the browser window that includes the Back and Forward buttons.
The inability, of the sender of a message, to deny having sent the message. A regular hand-written signature provides one form of nonrepudiation. A digital signature provides another.
notification bar
A bar that appears at the top of the content area to inform you about something that needs your attention, e.g. when the Password Manager can save a password for you, a popup has been blocked or an additional plugin is required.
object signing
A technology that allows software developers to sign Java code, JavaScript scripts, or any kind of file, and that allows users to identify the signers and control access by signed code to local system resources.
object-signing certificate
A certificate whose corresponding private key is used to sign objects such as code files. See also object signing.
OCSP (Online Certificate Status Protocol)
A set of rules that Certificate Manager follows to perform an online check of a certificate's validity each time the certificate is used. This process involves checking the certificate against a list of valid certificates maintained at a specified website. Your computer must be online for OCSP to work.
OPML (Outline Processor Markup Language)
An XML format used to list feed collections. Although broader in its specification, it is mainly used nowadays to export and import feed collections between different feed aggregators or readers, like &brandShortName;.
password-based authentication
Confident identification by means of a name and password. See also authentication.
Password Manager
The part of the browser 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 websites.
Personal Toolbar
The customizable toolbar that appears just below the location bar by default in the browser. It contains standard buttons such as Home, Bookmarks, and so on that you can add or remove. You can also add buttons for your favorite bookmarks, or folders containing groups of bookmarks.
Phishing is a fraudulent business scheme in which a party creates counterfeit websites, hijacking brand names of banks, e-retailers and credit card companies, trying to collect victims' personal information.
PKCS #11
The public-key cryptography standard that governs security devices such as smart cards. See also security device, smart card.
PKCS #11 module
A program on your computer that manages cryptographic services such as encryption and decryption using the PKCS #11 standard. Also called cryptographic modules, cryptographic service providers, or security modules, PKCS #11 modules control either hardware or software devices. A PKCS #11 module always controls one or more slots, which may be implemented as some form of physical reader (for example, for reading smart cards) or in software. Each slot for a PKCS #11 module can in turn contain a security device (also called token), which is the hardware or software device that provides cryptographic services and stores certificates and keys. Certificate Manager provides two built-in PKCS #11 modules. You may install additional modules on your computer to control smart card readers or other hardware devices.
PKI (public-key infrastructure)
The standards and services that facilitate the use of public-key cryptography and certificates in a networked environment.
A type of helper application that adds new capabilities to your browser, such as the ability to play audio or video clips. Unlike other kinds of helper applications, a plugin application installs itself into the Plugins directory within the main browser installation directory and typically can be opened within the browser itself (internally). For example, an audio plugin lets you listen to audio files on a web page or in an email message. Macromedia Flash Player and Java are both examples of plugin applications.
POP (Post Office Protocol)
A standard mail server protocol that requires you to download new messages to your local computer—although you can choose to leave copies on the server. With POP, you can store all your messages, including sent mail, drafts, and custom folders, on one computer only. By contrast, IMAP allows you to permanently store all your messages and any changes to them on the server, where you can access them from any computer. Most ISPs currently support POP.
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.
public key
One of a pair of keys used in public-key cryptography. The public key is distributed freely and published as part of a certificate. It is typically used to encrypt data sent to the public key's owner, who then decrypts the data with the corresponding private key.
public-key cryptography
A set of well-established techniques and standards that allow an entity (such as a person, an organization, or hardware such as a router) to verify its identity electronically or to sign and encrypt electronic data. Two keys are involved: a public key and a private key. The public key is published as part of a certificate, which associates that key with a particular identity. The corresponding private key is kept secret. Data encrypted with the public key can be decrypted only with the private key.
root CA
The certificate authority (CA) with a self-signed certificate at the top of a certificate chain. See also subordinate CA.
RSS (Really Simple Syndication)
An XML data format for web feeds.
search engine
A web-based program that allows users to search for and retrieve specific information from the World Wide Web (WWW). The search engine may search the full text of web documents or a list of keywords, or use librarians who review web documents and index them manually for retrieval. Typically, the user types a word or phrase, also called a query, into a search box, and the search engine displays links to relevant web pages.
secure authentication
A type of authentication which uses a secure connection so the communication between client and server is encrypted.
secure connection
A connection between a client and a server which uses some type of encryption (usually, SSL) to ensure it can't be intercepted by third-parties. Most of the time, the server is the one providing the certificate to identify itself.
security certificate
See certificate.
security device
Hardware or software that provides cryptographic services such as encryption and decryption and can store certificates and keys. A smart card is one example of a security device implemented in hardware. Certificate Manager contains its own built-in security device, called the software security device, that is always available while the browser is running. Each security device is protected by its own master password.
security module
See PKCS #11 module.
security token
See security device.
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.
server authentication
The process of identifying a server to a client by using a server SSL certificate. See also client authentication, SSL (Secure Sockets Layer).
server SSL certificate
A certificate that a server presents to a client to authenticate the server's identity using the SSL (Secure Sockets Layer) protocol.
signing certificate
A certificate whose corresponding private key is used to sign transmitted data, so that the receiver can verify the identity of the sender. Certificate authorities (CAs) often issue a signing certificate that will be used to sign email messages at the same time as an encryption certificate that will be used to encrypt email messages. See also dual key pairs, digital signature.
signing key
A private key used for signing only. A signing key and its equivalent public key, together with an encryption key and its equivalent private key, constitute dual key pairs.
A piece of hardware, or its equivalent in software, that is controlled by a PKCS #11 module and designed to contain a security device.
smart card
A small device, typically about the size of a credit card, that contains a microprocessor and is capable of storing cryptographic information (such as keys and certificates) and performing cryptographic operations. Smart cards use the PKCS #11 standard. A smart card is one kind of security device.
SMTP (Simple Mail Transfer Protocol)
A protocol that sends email messages across the Internet.
A protocol that a proxy server can use to accept requests from client users in an internal network so that it can forward them across the Internet.
software security device
The default security device used by Certificate Manager to store private keys associated with your certificates. In addition to private keys, the software security device stores the master key used by Password Manager to encrypt email passwords, website passwords, and other sensitive information. See also private key and master key.
Pretending to be someone else. For example, a person can pretend to have the email address jdoe@mozilla.com, or a computer can identify itself as a website called www.mozilla.com when it is not. Spoofing is one form of misrepresentation.
SSL (Secure Sockets Layer)
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.
An extension to common standard TCP protocols (like SMTP, POP or IMAP) so the client can tell the server to use TLS on the same TCP port as for non-secure connections.
Status Bar
The toolbar that appears at the bottom of any &brandShortName; window. It includes the Component Bar on the left and status icons on the right.
The entity (such as a person, organization, or router) identified by a certificate. In particular, the subject field of a certificate contains the certified entity's subject name and other characteristics.
subject name
A distinguished name (DN) that uniquely describes the subject of a certificate.
subordinate CA
A certificate authority (CA) whose certificate is signed by another subordinate CA or by the root CA. See also certificate chain, root CA.
symmetric encryption
An encryption method that uses a single cryptographic key to both encrypt and decrypt a given message.
tamper detection
A mechanism ensuring that data received in electronic form has not been tampered with; that is, that the data received corresponds entirely with the original version of the same data.
TCP/IP (Transmission Control Protocol/Internet Protocol)
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.
A type of add-on that changes the appearance of &brandShortName;.
See foreign cookie.
Transport Layer Security (TLS) is the new Internet Engineering Task Force (IETF) standard based on SSL (Secure Sockets Layer). See also SSL and encryption.
See security device.
A small box with text that appears when you hover your mouse's cursor over certain items. It usually contains information regarding the item being hovered over.
Confident reliance on a person or other entity. In the context of PKI (public-key infrastructure), trust usually refers to the relationship between the user of a certificate and the certificate authority (CA) that issued the certificate. If you use Certificate Manager to specify that you trust a CA, Certificate Manager trusts valid certificates issued by that CA unless you specify otherwise in the settings for individual certificates. You use the Authorities tab in Certificate Manager to specify the kinds of certificates you do or don't trust specific CAs to issue.
URL (Uniform Resource Locator)
The standardized address that tells your browser how to locate a file or other resource on the Web. For example: http://www.mozilla.org. You can type URLs into the browser's Location Bar to access web pages. URLs are also used in the links on web pages that you can click to go to other web pages. Also known as an Internet address or Web address.
web page
A single document on the World Wide Web that is specified by a unique address or URL and that 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 (WWW)
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 &brandShortName;).
WPAD (Web Proxy AutoDiscovery)
A proposed Internet protocol that allows a Web browser to automatically locate and interface with proxy services in a network.
XML (Extensible Markup Language)
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).
XSLT (Extensible Stylesheet Language Transformation)
A language used to convert an XML document into another XML document or into some other format.
XUL (XML User Interface Language)
A XML markup language for creating user interfaces in applications.