This is an accepted version of this page
85-632: Hypertext Transfer Protocol Secure ( HTTPS ) is an extension of the Hypertext Transfer Protocol (HTTP). It uses encryption for secure communication over a computer network , and is widely used on the Internet . In HTTPS, the communication protocol is encrypted using Transport Layer Security (TLS) or, formerly, Secure Sockets Layer (SSL). The protocol is therefore also referred to as HTTP over TLS , or HTTP over SSL . The principal motivations for HTTPS are authentication of
170-452: A local area network (LAN) within a limited area such as a home, school, computer laboratory, campus, or office building. This gives users the ability to move around within the area and remain connected to the network. Through a gateway , a WLAN can also provide a connection to the wider Internet . Wireless LANs based on the IEEE 802.11 standards are the most widely used computer networks in
255-407: A mouse click or by tapping the screen in a web browser . Development of HTTP was initiated by Tim Berners-Lee at CERN in 1989 and summarized in a simple document describing the behavior of a client and a server using the first HTTP version, named 0.9. That version was subsequently developed, eventually becoming the public 1.0. Development of early HTTP Requests for Comments (RFCs) started
340-469: A web of trust , the 2013 mass surveillance disclosures drew attention to certificate authorities as a potential weak point allowing man-in-the-middle attacks . An important property in this context is forward secrecy , which ensures that encrypted communications recorded in the past cannot be retrieved and decrypted should long-term secret keys or passwords be compromised in the future. Not all web servers provide forward secrecy. For HTTPS to be effective,
425-547: A wireless access point (WAP) that also serves as a bridge to other networks such as a local area network or the Internet. Since wireless communication uses a more open medium for communication in comparison to wired LANs, the 802.11 designers also included encryption mechanisms: Wired Equivalent Privacy (WEP), no longer considered secure, Wi-Fi Protected Access (WPA, WPA2, WPA3), to secure wireless computer networks. Many access points will also offer Wi-Fi Protected Setup ,
510-586: A WDS over some other solutions is that it preserves the MAC addresses of client packets across links between access points. An access point can be either a main, relay, or remote base station. A main base station is typically connected to the wired Ethernet. A relay base station relays data between remote base stations, wireless clients or other relay stations to either a main or another relay base station. A remote base station accepts connections from wireless clients and passes them to relay or main stations. Because data
595-439: A batch of RFCs was published, deprecating many of the previous documents and introducing a few minor changes and a refactoring of HTTP semantics description into a separate document. HTTP is a stateless application-level protocol and it requires a reliable network transport connection to exchange data between client and server. In HTTP implementations, TCP/IP connections are used using well-known ports (typically port 80 if
680-493: A client user interface called web browser . Berners-Lee designed HTTP in order to help with the adoption of his other idea: the "WorldWideWeb" project, which was first proposed in 1989, now known as the World Wide Web . The first web server went live in 1990. The protocol used had only one method, namely GET, which would request a page from a server. The response from the server was always an HTML page. In 1991,
765-474: A client failing to properly encode the request-target. Since 2016 many product managers and developers of user agents (browsers, etc.) and web servers have begun planning to gradually deprecate and dismiss support for HTTP/0.9 protocol, mainly for the following reasons: In 2020, the first drafts HTTP/3 were published and major web browsers and web servers started to adopt it. On 6 June 2022, IETF standardized HTTP/3 as RFC 9114 . In June 2022,
850-699: A correctly configured web server, eavesdroppers can infer the IP address and port number of the web server, and sometimes even the domain name (e.g. www.example.org, but not the rest of the URL) that a user is communicating with, along with the amount of data transferred and the duration of the communication, though not the content of the communication. Web browsers know how to trust HTTPS websites based on certificate authorities that come pre-installed in their software. Certificate authorities are in this way being trusted by web browser creators to provide valid certificates. Therefore,
935-421: A far future version of HTTP called HTTP-NG (HTTP Next Generation) that would have solved all remaining problems, of previous versions, related to performances, low latency responses, etc. but this work started only a few years later and it was never completed. In May 1996, RFC 1945 was published as a final HTTP/1.0 revision of what had been used in previous 4 years as a pre-standard HTTP/1.0-draft which
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#17327650006651020-671: A few years later in a coordinated effort by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C), with work later moving to the IETF. HTTP/1 was finalized and fully documented (as version 1.0) in 1996. It evolved (as version 1.1) in 1997 and then its specifications were updated in 1999, 2014, and 2022. Its secure variant named HTTPS is used by more than 85% of websites. HTTP/2 , published in 2015, provides
1105-536: A globally routable address, by relaying messages with external servers. To allow intermediate HTTP nodes (proxy servers, web caches, etc.) to accomplish their functions, some of the HTTP headers (found in HTTP requests/responses) are managed hop-by-hop whereas other HTTP headers are managed end-to-end (managed only by the source client and by the target web server). HTTP is an application layer protocol designed within
1190-505: A group owner in the Wi-Fi Direct group. In one approach, the user sets up a P2P group owner manually. This method is also known as autonomous group owner ( autonomous GO ). In the second method, called negotiation-based group creation , two devices compete based on the group owner intent value. The device with higher intent value becomes a group owner and the second device becomes a client. Group owner intent value can depend on whether
1275-421: A more efficient expression of HTTP's semantics "on the wire". As of August 2024, it is supported by 66.2% of websites (35.3% HTTP/2 + 30.9% HTTP/3 with backwards compatibility) and supported by almost all web browsers (over 98% of users). It is also supported by major web servers over Transport Layer Security (TLS) using an Application-Layer Protocol Negotiation (ALPN) extension where TLS 1.2 or newer
1360-703: A number of types, including Extended Validation Certificates . Let's Encrypt , launched in April 2016, provides free and automated service that delivers basic SSL/TLS certificates to websites. According to the Electronic Frontier Foundation , Let's Encrypt will make switching from HTTP to HTTPS "as easy as issuing one command, or clicking one button." The majority of web hosts and cloud providers now leverage Let's Encrypt, providing free certificates to their customers. The system can also be used for client authentication in order to limit access to
1445-545: A particular address and port combination. In the past, this meant that it was not feasible to use name-based virtual hosting with HTTPS. A solution called Server Name Indication (SNI) exists, which sends the hostname to the server before encrypting the connection, although many old browsers do not support this extension. Support for SNI is available since Firefox 2, Opera 8, Apple Safari 2.1, Google Chrome 6, and Internet Explorer 7 on Windows Vista . A sophisticated type of man-in-the-middle attack called SSL stripping
1530-553: A quick, but no longer considered secure, method of joining a new device to an encrypted network. Most Wi-Fi networks are deployed in infrastructure mode . In infrastructure mode, wireless clients, such as laptops and smartphones, connect to the WAP to join the network. The WAP usually has a wired network connection and may have permanent wireless connections to other WAPs. WAPs are usually fixed and provide service to their client nodes within range. Some networks will have multiple WAPs using
1615-536: A server establishing a connection (real or virtual). An HTTP(S) server listening on that port accepts the connection and then waits for a client's request message. The client sends its HTTP request message. Upon receiving the request the server sends back an HTTP response message, which includes header(s) plus a body if it is required. The body of this response message is typically the requested resource, although an error message or other information may also be returned. At any time (for many reasons) client or server can close
1700-414: A site must be completely hosted over HTTPS. If some of the site's contents are loaded over HTTP (scripts or images, for example), or if only a certain page that contains sensitive information, such as a log-in page, is loaded over HTTPS while the rest of the site is loaded over plain HTTP, the user will be vulnerable to attacks and surveillance. Additionally, cookies on a site served through HTTPS must have
1785-711: A user should trust an HTTPS connection to a website if and only if all of the following are true: HTTPS is especially important over insecure networks and networks that may be subject to tampering. Insecure networks, such as public Wi-Fi access points, allow anyone on the same local network to packet-sniff and discover sensitive information not protected by HTTPS. Additionally, some free-to-use and paid WLAN networks have been observed tampering with webpages by engaging in packet injection in order to serve their own ads on other websites. This practice can be exploited maliciously in many ways, such as by injecting malware onto webpages and stealing users' private information. HTTPS
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#17327650006651870-762: A warning across the entire window. Newer browsers also prominently display the site's security information in the address bar . Extended validation certificates show the legal entity on the certificate information. Most browsers also display a warning to the user when visiting a site that contains a mixture of encrypted and unencrypted content. Additionally, many web filters return a security warning when visiting prohibited websites. The Electronic Frontier Foundation , opining that "In an ideal world, every web request could be defaulted to HTTPS", has provided an add-on called HTTPS Everywhere for Mozilla Firefox , Google Chrome , Chromium , and Android , which enables HTTPS by default for hundreds of frequently used websites. Forcing
1955-472: A web browser to load only HTTPS content has been supported in Firefox starting in version 83. Starting in version 94, Google Chrome is able to "always use secure connections" if toggled in the browser's settings. The security of HTTPS is that of the underlying TLS, which typically uses long-term public and private keys to generate a short-term session key , which is then used to encrypt the data flow between
2040-604: A web server to accept HTTPS connections, the administrator must create a public key certificate for the web server. This certificate must be signed by a trusted certificate authority for the web browser to accept it without warning. The authority certifies that the certificate holder is the operator of the web server that presents it. Web browsers are generally distributed with a list of signing certificates of major certificate authorities so that they can verify certificates signed by them. A number of commercial certificate authorities exist, offering paid-for SSL/TLS certificates of
2125-422: A web server to authorized users. To do this, the site administrator typically creates a certificate for each user, which the user loads into their browser. Normally, the certificate contains the name and e-mail address of the authorized user and is automatically checked by the server on each connection to verify the user's identity, potentially without even requiring a password. An important property in this context
2210-1054: Is perfect forward secrecy (PFS). Possessing one of the long-term asymmetric secret keys used to establish an HTTPS session should not make it easier to derive the short-term session key to then decrypt the conversation, even at a later time. Diffie–Hellman key exchange (DHE) and Elliptic-curve Diffie–Hellman key exchange (ECDHE) are in 2013 the only schemes known to have that property. In 2013, only 30% of Firefox, Opera, and Chromium Browser sessions used it, and nearly 0% of Apple's Safari and Microsoft Internet Explorer sessions. TLS 1.3, published in August 2018, dropped support for ciphers without forward secrecy. As of February 2019, 96.6% of web servers surveyed support some form of forward secrecy, and 52.1% will use forward secrecy with most browsers. As of July 2023, 99.6% of web servers surveyed support some form of forward secrecy, and 75.2% will use forward secrecy with most browsers. A certificate may be revoked before it expires, for example because
2295-495: Is a revision of previous HTTP/2 in order to use QUIC + UDP transport protocols instead of TCP. Before that version, TCP/IP connections were used; but now, only the IP layer is used (which UDP, like TCP, builds on). This slightly improves the average speed of communications and to avoid the occasional (very rare) problem of TCP connection congestion that can temporarily block or slow down the data flow of all its streams (another form of " head of line blocking "). The term hypertext
2380-599: Is a set of all stations that can communicate with each other at PHY layer. Every BSS has an identification (ID) called the BSSID, which is the MAC address of the access point servicing the BSS. There are two types of BSS: Independent BSS (also referred to as IBSS), and infrastructure BSS. An independent BSS (IBSS) is an ad hoc network that contains no access points, which means they cannot connect to any other basic service set. In an IBSS
2465-652: Is also important for connections over the Tor network , as malicious Tor nodes could otherwise damage or alter the contents passing through them in an insecure fashion and inject malware into the connection. This is one reason why the Electronic Frontier Foundation and the Tor Project started the development of HTTPS Everywhere , which is included in Tor Browser. As more information is revealed about global mass surveillance and criminals stealing personal information,
2550-403: Is an accepted version of this page HTTP ( Hypertext Transfer Protocol ) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web , where hypertext documents include hyperlinks to other resources that the user can easily access, for example by
2635-544: Is designed to withstand such attacks and is considered secure against them (with the exception of HTTPS implementations that use deprecated versions of SSL). HTTP operates at the highest layer of the TCP/IP model —the application layer ; as does the TLS security protocol (operating as a lower sublayer of the same layer), which encrypts an HTTP message prior to transmission and decrypts a message upon arrival. Strictly speaking, HTTPS
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2720-439: Is forwarded wirelessly, consuming wireless bandwidth, throughput in this method is halved for wireless clients not connected to a main base station. Connections between base stations are done at layer-2 and do not involve or require layer-3 IP addresses. WDS capability may also be referred to as repeater mode because it appears to bridge and accept wireless clients at the same time (unlike traditional bridging). All base stations in
2805-462: Is in contrast to Ethernet which uses carrier-sense multiple access with collision detection (CSMA/CD). The 802.11 specification includes provisions designed to minimize collisions because mobile units have to contend with the hidden node problem where two mobile units may both be in range of a common access point, but out of range of each other. A bridge can be used to connect networks, typically of different types. A wireless Ethernet bridge allows
2890-513: Is nearly identical to the PHY of HiperLAN/2. In 2009, 802.11n was added to 802.11. It operates in both the 2.4 GHz and 5 GHz bands at a maximum data transfer rate of 600 Mbit/s. Most newer routers are dual-band and able to utilize both wireless bands. This allows data communications to avoid the crowded 2.4 GHz band , which is also shared with Bluetooth devices and microwave ovens . The 5 GHz band also has more channels than
2975-476: Is not a separate protocol, but refers to the use of ordinary HTTP over an encrypted SSL/TLS connection. HTTPS encrypts all message contents, including the HTTP headers and the request/response data. With the exception of the possible CCA cryptographic attack described in the limitations section below, an attacker should at most be able to discover that a connection is taking place between two parties, along with their domain names and IP addresses. To prepare
3060-457: Is only performed by the server. The mutual version requires the user to install a personal client certificate in the web browser for user authentication. In either case, the level of protection depends on the correctness of the implementation of the software and the cryptographic algorithms in use. SSL/TLS does not prevent the indexing of the site by a web crawler , and in some cases the URI of
3145-480: Is recommended to use HTTP Strict Transport Security (HSTS) with HTTPS to protect users from man-in-the-middle attacks, especially SSL stripping . HTTPS should not be confused with the seldom-used Secure HTTP (S-HTTP) specified in RFC 2660. As of April 2018, 33.2% of Alexa top 1,000,000 websites use HTTPS as default and 70% of page loads (measured by Firefox Telemetry) use HTTPS. As of December 2022, 58.4% of
3230-401: Is required. HTTP/3 , the successor to HTTP/2, was published in 2022. As of February 2024, it is now used on 30.9% of websites and is supported by most web browsers, i.e. (at least partially) supported by 97% of users. HTTP/3 uses QUIC instead of TCP for the underlying transport protocol. Like HTTP/2, it does not obsolete previous major versions of the protocol. Support for HTTP/3
3315-525: The Independent Basic Service Set (IBSS). A Wi-Fi Direct network is a different type of wireless network where stations communicate peer-to-peer. In a peer-to-peer network wireless devices within range of each other can discover and communicate directly without involving central access points. In a Wi-Fi P2P group, the group owner operates as an access point and all other devices are clients. There are two main methods to establish
3400-422: The client whereas a process , named web server , running on a computer hosting one or more websites may be the server . The client submits an HTTP request message to the server. The server, which provides resources such as HTML files and other content or performs other functions on behalf of the client, returns a response message to the client. The response contains completion status information about
3485-568: The secure attribute enabled. On a site that has sensitive information on it, the user and the session will get exposed every time that site is accessed with HTTP instead of HTTPS. HTTPS URLs begin with "https://" and use port 443 by default, whereas, HTTP URLs begin with "http://" and use port 80 by default. HTTP is not encrypted and thus is vulnerable to man-in-the-middle and eavesdropping attacks , which can let attackers gain access to website accounts and sensitive information, and modify webpages to inject malware or advertisements. HTTPS
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3570-599: The 2.4 GHz band, permitting a greater number of devices to share the space. Not all WLAN channels are available in all regions. A HomeRF group formed in 1997 to promote a technology aimed at residential use, but it disbanded in January 2003. All components that can connect into a wireless medium in a network are referred to as stations. All stations are equipped with wireless network interface controllers . Wireless stations fall into two categories: wireless access points (WAPs) and clients. WAPs are base stations for
3655-731: The HTTP Working Group released an updated six-part HTTP/1.1 specification obsoleting RFC 2616 : In RFC 7230 Appendix-A, HTTP/0.9 was deprecated for servers supporting HTTP/1.1 version (and higher): Since HTTP/0.9 did not support header fields in a request, there is no mechanism for it to support name-based virtual hosts (selection of resource by inspection of the Host header field). Any server that implements name-based virtual hosts ought to disable support for HTTP/0.9 . Most requests that appear to be HTTP/0.9 are, in fact, badly constructed HTTP/1.x requests caused by
3740-461: The Internet's 135,422 most popular websites have a secure implementation of HTTPS, However, despite TLS 1.3's release in 2018, adoption has been slow, with many still remaining on the older TLS 1.2 protocol. Most browsers display a warning if they receive an invalid certificate. Older browsers, when connecting to a site with an invalid certificate, would present the user with a dialog box asking whether they wanted to continue. Newer browsers display
3825-893: The STAs are configured in ad hoc (peer-to-peer) mode. An extended service set (ESS) is a set of connected BSSs. Access points in an ESS are connected by a distribution system. Each ESS has an ID called the SSID which is a 32-byte (maximum) character string. A distribution system (DS) connects access points in an extended service set. The concept of a DS can be used to increase network coverage through roaming between cells. DS can be wired or wireless. Current wireless distribution systems are mostly based on WDS or Mesh protocols , though other systems are in use. The IEEE 802.11 has two basic modes of operation: infrastructure and ad hoc mode. In ad hoc mode, mobile units communicate directly peer-to-peer. In infrastructure mode, mobile units communicate through
3910-443: The accessed website and protection of the privacy and integrity of the exchanged data while it is in transit. It protects against man-in-the-middle attacks , and the bidirectional block cipher encryption of communications between a client and server protects the communications against eavesdropping and tampering . The authentication aspect of HTTPS requires a trusted third party to sign server-side digital certificates . This
3995-613: The browser whether the certificate is still valid or not. The CA may also issue a CRL to tell people that these certificates are revoked. CRLs are no longer required by the CA/Browser forum, nevertheless, they are still widely used by the CAs. Most revocation statuses on the Internet disappear soon after the expiration of the certificates. SSL (Secure Sockets Layer) and TLS (Transport Layer Security) encryption can be configured in two modes: simple and mutual . In simple mode, authentication
4080-412: The client and the server. X.509 certificates are used to authenticate the server (and sometimes the client as well). As a consequence, certificate authorities and public key certificates are necessary to verify the relation between the certificate and its owner, as well as to generate, sign, and administer the validity of certificates. While this can be more beneficial than verifying the identities via
4165-442: The client. This prompted the development of a countermeasure in HTTP called HTTP Strict Transport Security . HTTPS has been shown to be vulnerable to a range of traffic analysis attacks. Traffic analysis attacks are a type of side-channel attack that relies on variations in the timing and size of traffic in order to infer properties about the encrypted traffic itself. Traffic analysis is possible because SSL/TLS encryption changes
4250-406: The communication is authenticated . This is the case with HTTP transactions over the Internet, where typically only the server is authenticated (by the client examining the server's certificate ). HTTPS creates a secure channel over an insecure network. This ensures reasonable protection from eavesdroppers and man-in-the-middle attacks , provided that adequate cipher suites are used and that
4335-444: The connection is unencrypted or port 443 if the connection is encrypted, see also List of TCP and UDP port numbers ). In HTTP/2, a TCP/IP connection plus multiple protocol channels are used. In HTTP/3, the application transport protocol QUIC over UDP is used. Data is exchanged through a sequence of request–response messages which are exchanged by a session layer transport connection. An HTTP client initially tries to connect to
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#17327650006654420-439: The connection of devices on a wired Ethernet network to a wireless network. The bridge acts as the connection point to the wireless LAN. A wireless distribution system (WDS) enables the wireless interconnection of access points in an IEEE 802.11 network. It allows a wireless network to be expanded using multiple access points without the need for a wired backbone to link them, as is traditionally required. The notable advantage of
4505-496: The connection. Closing a connection is usually advertised in advance by using one or more HTTP headers in the last request/response message sent to server or client. In HTTP/0.9 , the TCP/IP connection is always closed after server response has been sent, so it is never persistent. Wireless LAN A wireless LAN ( WLAN ) is a wireless computer network that links two or more devices using wireless communication to form
4590-472: The contents of traffic, but has minimal impact on the size and timing of traffic. In May 2010, a research paper by researchers from Microsoft Research and Indiana University discovered that detailed sensitive user data can be inferred from side channels such as packet sizes. The researchers found that, despite HTTPS protection in several high-profile, top-of-the-line web applications in healthcare, taxation, investment, and web search, an eavesdropper could infer
4675-475: The encrypted resource can be inferred by knowing only the intercepted request/response size. This allows an attacker to have access to the plaintext (the publicly available static content), and the encrypted text (the encrypted version of the static content), permitting a cryptographic attack . Because TLS operates at a protocol level below that of HTTP and has no knowledge of the higher-level protocols, TLS servers can only strictly present one certificate for
4760-416: The establishment of TCP connections presents considerable overhead, especially under high traffic conditions. HTTP/2 is a revision of previous HTTP/1.1 in order to maintain the same client–server model and the same protocol methods but with these differences in order: HTTP/2 communications therefore experience much less latency and, in most cases, even higher speeds than HTTP/1.1 communications. HTTP/3
4845-443: The first documented official version of HTTP was written as a plain document, less than 700 words long, and this version was named HTTP/0.9, which supported only GET method, allowing clients to only retrieve HTML documents from the server, but not supporting any other file formats or information upload. Since 1992, a new document was written to specify the evolution of the basic protocol towards its next full version. It supported both
4930-753: The framework of the Internet protocol suite . Its definition presumes an underlying and reliable transport layer protocol. In HTTP/3 , the Transmission Control Protocol (TCP) is no longer used, but the older versions are still more used and they most commonly use TCP. They have also been adapted to use unreliable protocols such as the User Datagram Protocol (UDP), which HTTP/3 also (indirectly) always builds on, for example in HTTPU and Simple Service Discovery Protocol (SSDP). HTTP resources are identified and located on
5015-512: The group stopped its activity passing the technical problems to IETF. In 2007, the IETF HTTP Working Group (HTTP WG bis or HTTPbis) was restarted firstly to revise and clarify previous HTTP/1.1 specifications and secondly to write and refine future HTTP/2 specifications (named httpbis). In 2009, Google , a private company, announced that it had developed and tested a new HTTP binary protocol named SPDY . The implicit aim
5100-570: The illnesses/medications/surgeries of the user, his/her family income, and investment secrets. The fact that most modern websites, including Google, Yahoo!, and Amazon, use HTTPS causes problems for many users trying to access public Wi-Fi hot spots, because a captive portal Wi-Fi hot spot login page fails to load if the user tries to open an HTTPS resource. Several websites, such as NeverSSL, guarantee that they will always remain accessible by HTTP. Netscape Communications created HTTPS in 1994 for its Netscape Navigator web browser. Originally, HTTPS
5185-536: The internet with portable wireless devices. Norman Abramson , a professor at the University of Hawaii , developed the world's first wireless computer communication network, ALOHAnet . The system became operational in 1971 and included seven computers deployed over four islands to communicate with the central computer on the Oahu island without using phone lines. Wireless LAN hardware initially cost so much that it
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#17327650006655270-458: The need to start to focus on a new HTTP/2 protocol (while finishing the revision of HTTP/1.1 specifications), maybe taking in consideration ideas and work done for SPDY. After a few months about what to do to develop a new version of HTTP, it was decided to derive it from SPDY. In May 2015, HTTP/2 was published as RFC 7540 and quickly adopted by all web browsers already supporting SPDY and more slowly by web servers. In June 2014,
5355-767: The network by Uniform Resource Locators (URLs), using the Uniform Resource Identifiers (URIs) schemes http and https . As defined in RFC 3986 , URIs are encoded as hyperlinks in HTML documents, so as to form interlinked hypertext documents. In HTTP/1.0 a separate TCP connection to the same server is made for every resource request. In HTTP/1.1 instead a TCP connection can be reused to make multiple resource requests (i.e. of HTML pages, frames, images, scripts , stylesheets , etc.). HTTP/1.1 communications therefore experience less latency as
5440-447: The new versions of browsers and servers was rapid. In March 1996, one web hosting company reported that over 40% of browsers in use on the Internet used the new HTTP/1.1 header "Host" to enable virtual hosting , and that by June 1996, 65% of all browsers accessing their servers were pre-standard HTTP/1.1 compliant. In January 1997, RFC 2068 was officially released as HTTP/1.1 specifications. In June 1999, RFC 2616
5525-486: The original, non-secure HTTP, primarily to protect page authenticity on all types of websites, secure accounts, and keep user communications, identity, and web browsing private. The Uniform Resource Identifier (URI) scheme HTTPS has identical usage syntax to the HTTP scheme. However, HTTPS signals the browser to use an added encryption layer of SSL/TLS to protect the traffic. SSL/TLS is especially suited for HTTP, since it can provide some protection even if only one side of
5610-811: The request and may also contain requested content in its message body. A web browser is an example of a user agent (UA). Other types of user agent include the indexing software used by search providers ( web crawlers ), voice browsers , mobile apps , and other software that accesses, consumes, or displays web content. HTTP is designed to permit intermediate network elements to improve or enable communications between clients and servers. High-traffic websites often benefit from web cache servers that deliver content on behalf of upstream servers to improve response time. Web browsers cache previously accessed web resources and reuse them, whenever possible, to reduce network traffic. HTTP proxy servers at private network boundaries can facilitate communication for clients without
5695-417: The same SSID and security arrangement. In that case, connecting to any WAP on that network joins the client to the network, and the client software will try to choose the WAP that gives the best service, such as the WAP with the strongest signal. An ad hoc network is a network where stations communicate only peer-to-peer (P2P). There is no base and no one gives permission to talk. This is accomplished using
5780-520: The secrecy of the private key has been compromised. Newer versions of popular browsers such as Firefox , Opera , and Internet Explorer on Windows Vista implement the Online Certificate Status Protocol (OCSP) to verify that this is not the case. The browser sends the certificate's serial number to the certificate authority or its delegate via OCSP (Online Certificate Status Protocol) and the authority responds, telling
5865-490: The server certificate is verified and trusted. Because HTTPS piggybacks HTTP entirely on top of TLS, the entirety of the underlying HTTP protocol can be encrypted. This includes the request's URL , query parameters, headers, and cookies (which often contain identifying information about the user). However, because website addresses and port numbers are necessarily part of the underlying TCP/IP protocols, HTTPS cannot protect their disclosure. In practice this means that even on
5950-417: The simple request method of the 0.9 version and the full GET request that included the client HTTP version. This was the first of the many unofficial HTTP/1.0 drafts that preceded the final work on HTTP/1.0. After having decided that new features of HTTP protocol were required and that they had to be fully documented as official RFCs , in early 1995 the HTTP Working Group (HTTP WG, led by Dave Raggett )
6035-515: The use of HTTPS security on all websites is becoming increasingly important regardless of the type of Internet connection being used. Even though metadata about individual pages that a user visits might not be considered sensitive, when aggregated it can reveal a lot about the user and compromise the user's privacy. Deploying HTTPS also allows the use of HTTP/2 and HTTP/3 (and their predecessors SPDY and QUIC ), which are new HTTP versions designed to reduce page load times, size, and latency. It
6120-428: The wireless device performs a cross-connection between an infrastructure WLAN service and a P2P group, available power in the wireless device, whether the wireless device is already a group owner in another group or a received signal strength of the first wireless device. IEEE 802.11 defines the PHY and medium access control (MAC) layers based on carrier-sense multiple access with collision avoidance (CSMA/CA). This
6205-406: The wireless network. They transmit and receive radio frequencies for wireless-enabled devices to communicate with. Wireless clients can be mobile devices such as laptops, personal digital assistants , VoIP phones and other smartphones , or non-portable devices such as desktop computers , printers, and workstations that are equipped with a wireless network interface. The basic service set (BSS)
6290-495: The world. These are commonly called Wi-Fi , which is a trademark belonging to the Wi-Fi Alliance . They are used for home and small office networks that link together laptop computers , printers , smartphones , Web TVs and gaming devices with a wireless network router , which links them to the internet. Hotspots provided by routers at restaurants, coffee shops, hotels, libraries, and airports allow consumers to access
6375-465: Was added to Cloudflare and Google Chrome first, and is also enabled in Firefox . HTTP/3 has lower latency for real-world web pages, if enabled on the server, and loads faster than with HTTP/2, in some cases over three times faster than HTTP/1.1 (which is still commonly only enabled). HTTP functions as a request–response protocol in the client–server model . A web browser , for example, may be
6460-503: Was already used by many web browsers and web servers. In early 1996 developers started to even include unofficial extensions of the HTTP/1.0 protocol (i.e. keep-alive connections, etc.) into their products by using drafts of the upcoming HTTP/1.1 specifications. Since early 1996, major web browsers and web server developers also started to implement new features specified by pre-standard HTTP/1.1 drafts specifications. End-user adoption of
6545-466: Was coined by Ted Nelson in 1965 in the Xanadu Project , which was in turn inspired by Vannevar Bush 's 1930s vision of the microfilm-based information retrieval and management " memex " system described in his 1945 essay " As We May Think ". Tim Berners-Lee and his team at CERN are credited with inventing the original HTTP, along with HTML and the associated technology for a web server and
6630-482: Was constituted with the aim to standardize and expand the protocol with extended operations, extended negotiation, richer meta-information, tied with a security protocol which became more efficient by adding additional methods and header fields . The HTTP WG planned to revise and publish new versions of the protocol as HTTP/1.0 and HTTP/1.1 within 1995, but, because of the many revisions, that timeline lasted much more than one year. The HTTP WG planned also to specify
6715-424: Was historically an expensive operation, which meant fully authenticated HTTPS connections were usually found only on secured payment transaction services and other secured corporate information systems on the World Wide Web . In 2016, a campaign by the Electronic Frontier Foundation with the support of web browser developers led to the protocol becoming more prevalent. HTTPS is now used more often by web users than
6800-460: Was only used as an alternative to cabled LAN in places where cabling was difficult or impossible. Early development included industry-specific solutions and proprietary protocols, but at the end of the 1990s these were replaced by technical standards , primarily the various versions of IEEE 802.11 (in products using the Wi-Fi brand name). Beginning in 1991, a European alternative known as HiperLAN/1
6885-456: Was presented at the 2009 Blackhat Conference . This type of attack defeats the security provided by HTTPS by changing the https: link into an http: link, taking advantage of the fact that few Internet users actually type "https" into their browser interface: they get to a secure site by clicking on a link, and thus are fooled into thinking that they are using HTTPS when in fact they are using HTTP. The attacker then communicates in clear with
6970-517: Was pursued by the European Telecommunications Standards Institute (ETSI) with a first version approved in 1996. This was followed by a HiperLAN/2 functional specification with ATM influences accomplished February 2000. Neither European standard achieved the commercial success of 802.11, although much of the work on HiperLAN/2 has survived in the physical specification ( PHY ) for IEEE 802.11a , which
7055-433: Was released to include all improvements and updates based on previous (obsolete) HTTP/1.1 specifications. Resuming the old 1995 plan of previous HTTP Working Group, in 1997 an HTTP-NG Working Group was formed to develop a new HTTP protocol named HTTP-NG (HTTP New Generation). A few proposals / drafts were produced for the new protocol to use multiplexing of HTTP transactions inside a single TCP/IP connection, but in 1999,
7140-463: Was to greatly speed up web traffic (specially between future web browsers and its servers). SPDY was indeed much faster than HTTP/1.1 in many tests and so it was quickly adopted by Chromium and then by other major web browsers. Some of the ideas about multiplexing HTTP streams over a single TCP/IP connection were taken from various sources, including the work of W3C HTTP-NG Working Group. In January–March 2012, HTTP Working Group (HTTPbis) announced
7225-570: Was used with the SSL protocol. As SSL evolved into Transport Layer Security (TLS), HTTPS was formally specified by RFC 2818 in May 2000. Google announced in February 2018 that its Chrome browser would mark HTTP sites as "Not Secure" after July 2018. This move was to encourage website owners to implement HTTPS, as an effort to make the World Wide Web more secure. Hypertext Transfer Protocol This
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