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HTTPS (also called HTTP over TLS, HTTP over SSL,〔(【引用サイトリンク】 title=Enabling HTTP Over SSL )〕 and HTTP Secure) is a protocol for secure communication over a computer network which is widely used on the Internet. HTTPS consists of communication over Hypertext Transfer Protocol (HTTP) within a connection encrypted by Transport Layer Security or its predecessor, Secure Sockets Layer. The main motivation for HTTPS is authentication of the visited website and protection of the privacy and integrity of the exchanged data. In its popular deployment on the internet, HTTPS provides authentication of the website and associated web server with which one is communicating, which protects against man-in-the-middle attacks. Additionally, it provides bidirectional encryption of communications between a client and server, which protects against eavesdropping and tampering with and/or forging the contents of the communication.〔(【引用サイトリンク】title=HTTPS Everywhere FAQ )〕 In practice, this provides a reasonable guarantee that one is communicating with precisely the website that one intended to communicate with (as opposed to an impostor), as well as ensuring that the contents of communications between the user and site cannot be read or forged by any third party. Historically, HTTPS connections were primarily used for payment transactions on the World Wide Web, e-mail and for sensitive transactions in corporate information systems. In the late 2000s and early 2010s, HTTPS began to see widespread use for protecting page authenticity on all types of websites, securing accounts and keeping user communications, identity and web browsing private. ==Overview== The ''HTTPS'' uniform resource identifier (URI) scheme has identical syntax to the standard HTTP scheme, aside from its scheme token. 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 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 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 URL (which particular web page was requested), query parameters, headers, and cookies (which often contain identity information about the user). However, because host (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 a correctly configured web server, eavesdroppers can infer the IP address and port number of the web server (sometimes even the domain name e.g. www.example.org, but not the rest of the URL) that one is communicating with as well as the amount (data transferred) and duration (length of session) 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 (such as Symantec, Comodo, GoDaddy and GlobalSign) are in this way being trusted by web browser creators to provide valid certificates. Therefore, a user should trust an HTTPS connection to a website if and only if all of the following are true: * The user trusts that the browser software correctly implements HTTPS with correctly pre-installed certificate authorities. * The user trusts the certificate authority to vouch only for legitimate websites. * The website provides a valid certificate, which means it was signed by a trusted authority. * The certificate correctly identifies the website (e.g., when the browser visits "https://example.com", the received certificate is properly for "example.com" and not some other entity). * The user trusts that the protocol's encryption layer (SSL/TLS) is sufficiently secure against eavesdroppers. HTTPS is especially important over insecure networks (such as public WiFi access points), as anyone on the same local network can packet sniff and discover sensitive information not protected by HTTPS. Additionally, many free to use and even paid for WLAN networks engage in packet injection in order to serve their own ads on webpages. However, this can be exploited maliciously in many ways, such as injecting malware onto webpages and stealing users' private information.〔(【引用サイトリンク】url=http://justinsomnia.org/2012/04/hotel-wifi-javascript-injection/ )〕 HTTPS is also very important for connections over the Tor anonymity network, as malicious Tor nodes can 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 the Tor Browser Bundle.〔(【引用サイトリンク】title=Tor )〕 As more information is revealed about global mass surveillance and hackers stealing personal information, the use of HTTPS security on all websites is becoming increasingly important regardless of the type of Internet connection being used. While metadata about individual pages that a user visits is not sensitive, when combined together, they can reveal a lot about the user and compromise the user's privacy.〔〔 Deploying HTTPS also allows the use of SPDY/HTTP/2, that are new generations of HTTP, designed to reduce page load times and latency. It is recommended to use HTTP Strict Transport Security (HSTS) with HTTPS to protect users from man-in-the-middle attacks, especially SSL stripping.〔(【引用サイトリンク】url=https://www.eff.org/https-everywhere/deploying-https )〕〔(【引用サイトリンク】title=HTTP Strict Transport Security )〕 HTTPS should not be confused with the little-used Secure HTTP (S-HTTP) specified in RFC 2660. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「HTTPS」の詳細全文を読む スポンサード リンク
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