World Wide Web

Webthe webweb-based
The scheme specifiers and at the start of a web URI refer to Hypertext Transfer Protocol or HTTP Secure, respectively. They specify the communication protocol to use for the request and response. The HTTP protocol is fundamental to the operation of the World Wide Web, and the added encryption layer in HTTPS is essential when browsers send or retrieve confidential data, such as passwords or banking information. Web browsers usually automatically prepend to user-entered URIs, if omitted. For criminals, the Web has become a venue to spread malware and engage in a range of cybercrimes, including identity theft, fraud, espionage and intelligence gathering.


web sitewebsitesonline
Web pages are accessed and transported with the Hypertext Transfer Protocol (HTTP), which may optionally employ encryption (HTTP Secure, HTTPS) to provide security and privacy for the user. The user's application, often a web browser, renders the page content according to its HTML markup instructions onto a display terminal. Hyperlinking between web pages conveys to the reader the site structure and guides the navigation of the site, which often starts with a home page containing a directory of the site web content. Some websites require user registration or subscription to access content.

Web server

webserverweb serversserver
A web server processes incoming network requests over HTTP and several other related protocols. The primary function of a web server is to store, process and deliver web pages to clients. The communication between client and server takes place using the Hypertext Transfer Protocol (HTTP). Pages delivered are most frequently HTML documents, which may include images, style sheets and scripts in addition to the text content. A user agent, commonly a web browser or web crawler, initiates communication by making a request for a specific resource using HTTP and the server responds with the content of that resource or an error message if unable to do so.

Public key infrastructure

PKIpublic-key infrastructurepublic key infrastructure (PKI)
HTTP/2, the latest version of HTTP protocol allows unsecured connections in theory, in practice major browser companies have made it clear that they would support this state-of-art protocol only over a PKI secured TLS connection. Web browser implementation of HTTP/2 including Edge from Microsoft, Chrome from Google, Firefox from Mozilla, and Opera supports HTTP/2 only over TLS by using ALPN extension of TLS protocol. This would mean that to get the speed benefits of HTTP/2, website owners would be forced to purchase SSL certificates controlled by corporations such as Symantec. Current web browsers carry pre-installed intermediary certificates issued and signed by a Certificate Authority.

Extended Validation Certificate

Extended ValidationEVExtended Validation certificates
An important motivation for using digital certificates with SSL/TLS was to add trust to online transactions by requiring website operators to undergo vetting with a certificate authority (CA) in order to get a certificate. However, commercial pressures have led some CAs to introduce "domain-validated" certificates. Domain-validated certificates existed before validation standards, and generally only require some proof of domain control. In particular, domain-validated certificates do not assert that a given legal entity has any relationship with the domain, although the domain may resemble a particular legal entity.

HTTP Public Key Pinning

HTTP Public Key Pinning (HPKP) is an Internet security mechanism delivered via an HTTP header which allows HTTPS websites to resist impersonation by attackers using mis-issued or otherwise fraudulent digital certificates. It does this by delivering a set of public keys to the client (e.g. web browser), which should be the only ones trusted for future connections to the same domain name. For example, attackers might compromise a certificate authority, and then mis-issue certificates for a web origin.


HTTP version 2
On February 9, 2015, Google announced plans to remove support for SPDY in Chrome in favor of support for HTTP/2. That took effect, starting with Chrome 51. HTTP/2 is defined for both HTTP URIs (i.e. without encryption) and for HTTPS URIs (over TLS using ALPN extension where TLS 1.2 or newer is required). Although the standard itself does not require usage of encryption, all major client implementations (Firefox, Chrome, Safari, Opera, IE, Edge) have stated that they will only support HTTP/2 over TLS, which makes encryption de facto mandatory. HTTP/2's development process and the protocol itself have faced criticism.

Internet Explorer

IEMicrosoft Internet ExplorerExplorer
ShDocVw.dll provides the navigation, local caching and history functionalities for the browser. BrowseUI.dll is responsible for rendering the browser user interface such as menus and toolbars. Bing Bar. History of the web browser. List of web browsers. Month of bugs. Web 2.0. Windows Filtering Platform. Winsock.

Secure Hypertext Transfer Protocol

Secure Hypertext Transfer Protocol (S-HTTP) is an obsolete alternative to the HTTPS protocol for encrypting web communications carried over HTTP. It was developed by Eric Rescorla and Allan M. Schiffman, and published in 1999 as RFC 2660. Web browsers typically use HTTP to communicate with web servers, sending and receiving information without encrypting it. For sensitive transactions, such as Internet e-commerce or online access to financial accounts, the browser and server must encrypt this information. HTTPS and S-HTTP were both defined in the mid-1990s to address this need.

Online Certificate Status Protocol

The Online Certificate Status Protocol (OCSP) is an Internet protocol used for obtaining the revocation status of an X.509 digital certificate. It is described in RFC 6960 and is on the Internet standards track. It was created as an alternative to certificate revocation lists (CRL), specifically addressing certain problems associated with using CRLs in a public key infrastructure (PKI). Messages communicated via OCSP are encoded in ASN.1 and are usually communicated over HTTP. The "request/response" nature of these messages leads to OCSP servers being termed OCSP responders. Some web browsers use OCSP to validate HTTPS certificates.

HTTP Strict Transport Security

limitationsStrict Transport SecurityStrict-Transport-Security
Many websites do not use TLS/SSL, therefore there is no way of knowing (without prior knowledge) whether the use of plain HTTP is due to an attack, or simply because the website hasn't implemented TLS/SSL. Additionally, no warnings are presented to the user during the downgrade process, making the attack fairly subtle to all but the most vigilant. Marlinspike's sslstrip tool fully automates the attack. HSTS addresses this problem by informing the browser that connections to the site should always use TLS/SSL. The HSTS header can be stripped by the attacker if this is the user's first visit.

HTTP cookie

cookiescookiepersistent cookie
This issue can be resolved by securing the communication between the user's computer and the server by employing Transport Layer Security (HTTPS protocol) to encrypt the connection. A server can specify the flag while setting a cookie, which will cause the browser to send the cookie only over an encrypted channel, such as an TLS connection. If an attacker is able to cause a DNS server to cache a fabricated DNS entry (called DNS cache poisoning), then this could allow the attacker to gain access to a user's cookies. For example, an attacker could use DNS cache poisoning to create a fabricated DNS entry of that points to the IP address of the attacker's server.

HTTPS Everywhere

In 2011, Vincent Toubiana and Vincent Verdot pointed out some drawbacks of the HTTPS Everywhere add-on, including that the list of services which support HTTPS needs maintaining, and that some services are redirected to HTTPS even though they are not yet available in HTTPS, not allowing the user of the extension to get to the service. Transport Layer Security (TLS) – Cryptographic protocols that provide communications security over a computer network. Privacy Badger – A free browser extension created by the EFF that blocks advertisements and tracking cookie s. Switzerland (software) – An open-source network monitoring utility developed by the EFF to monitor network traffic.

Google Chrome

ChromeChrome browserGoogle Chrome Extension
History of web browsers. List of web browsers.

Safari (web browser)

SafariApple SafariSafari web browser
History of web browsers. Internet Explorer for Mac, default web browser included in OS X before Safari. List of web browsers. Month of Bugs. Safari version history. United States v. Google Inc. in which the FTC alleged that Google misrepresented privacy assurances to Safari users.

Netscape Navigator

NavigatorNetscapeMosaic Netscape
Timeline of web browsers. Comparison of web browsers. List of web browsers. Netscape. Mosaic. Mozilla. Lou Montulli. Notice for Netscape Navigator 2.02 for OS/2 and Netscape Communicator 4.04 for OS/2 Users. The hidden features of Netscape Navigator 3.0. Netscape Browser Archive - Early Netscape, SillyDog701.

Public-key cryptography

public keypublic key cryptographyprivate key
S/MIME. GPG, an implementation of OpenPGP. Internet Key Exchange. PGP. ZRTP, a secure VoIP protocol. Transport Layer Security standardized by IETF and its predecessor Secure Socket Layer. SILC. SSH. Bitcoin. Off-the-Record Messaging. Books on cryptography. GNU Privacy Guard. ID-based encryption (IBE). Key escrow. Key-agreement protocol. PGP word list. Pretty Good Privacy. Pseudonymity. Public key fingerprint. Public key infrastructure (PKI). Quantum computing. Quantum cryptography. Secure Shell (SSH). Transport Layer Security (TLS). Symmetric-key algorithm. Threshold cryptosystem. IEEE 1363: Standard Specifications for Public-Key Cryptography.

Man-in-the-middle attack

man-in-the-middleman in the middle attackman in the middle
A public key infrastructure, such as Transport Layer Security, may harden Transmission Control Protocol against Man-in-the-middle-attacks. In such structures, clients and servers exchange certificates which are issued and verified by a trusted third party called a certificate authority (CA). If the original key to authenticate this CA has not been itself the subject of a MITM attack, then the certificates issued by the CA may be used to authenticate the messages sent by the owner of that certificate.

Opera (web browser)

OperaOpera web browserOpera browser
Otter Browser: An open-source web browser that aims to recreate some aspects of the classic Opera. Vivaldi: A freeware web browser by former Opera Software employees who were not satisfied by the development decisions of the company. History of the web browser. List of web browsers. Timeline of web browsers. Comparison of browser synchronizers. List of pop-up blocking software.

Let's Encrypt

Let’s Encrypt
Let's Encrypt is a certificate authority that provides X.509 certificates for Transport Layer Security (TLS) encryption at no charge. The certificate is valid for 90 days, during which renewal can take place at anytime. The offer is accompanied by an automated process designed to overcome manual creation, validation, signing, installation, and renewal of certificates for secure websites. It launched on April 12, 2016. The project claims its goal is to make encrypted connections to World Wide Web servers ubiquitous.

Digest access authentication

digest authenticationDigestDigest SSP
Nintendo DS Browser. Nokia 770 Browser. Sony Mylo 1's Browser. Wii Internet Channel Browser. AKA (security). JSON Web Token (JWT). Basic access authentication. RFC 2617. RFC 2069 (obsolete).

History of Firefox

Firefox QuantumPhoenix37
Firefox 37 was released on March 31, 2015, bringing a heartbeat user rating system, which provides user feedback about the Firefox, and improved protection against website impersonation via OneCRL centralized certificate revocation. Also, Bing search is changed to use HTTPS for secure searching, and added is support for opportunistic encryption of the HTTP traffic where the server supports HTTP/2's AltSvc feature. Firefox 37.0.1 was released on April 3, 2015 for desktop and Android, fixing security issues and several crash issues. It also disabled opportunistic encryption of the HTTP traffic introduced in 37.0.

Internet Explorer 8

Comparison of web browsers. Mandatory Integrity Control. Internet Explorer Developer Center on MSDN. Internet Explorer team blog.

Opportunistic encryption

auto-detectionopportunistically sign
For encrypting WWW/HTTP connections, HTTPS is typically used, which requires strict encryption and has significant administrative costs, both in terms of initial setup and continued maintenance costs for the website operator. Most browsers verify the webserver's identity to make sure that an SSL certificate is signed by a trusted certificate authority (which the administrator typically has to pay for) and has not expired, usually requiring the website operator to manually change the certificate every one or two years.

Certificate authority

certificate authoritiesCAcertification authority
Worldwide, the certificate authority business is fragmented, with national or regional providers dominating their home market. This is because many uses of digital certificates, such as for legally binding digital signatures, are linked to local law, regulations, and accreditation schemes for certificate authorities. However, the market for globally trusted TLS/SSL server certificates is largely held by a small number of multinational companies. This market has significant barriers to entry due to the technical requirements.