| HTTP |
|---|
 |
| Request methods |
| Header fields |
| Response status codes |
| Security access control methods |
| Security vulnerabilities |
Secure Hypertext Transfer Protocol (S-HTTP) is an obsolete alternative to the HTTPS protocol for encrypting web communications carried over the Internet. It was developed by Eric Rescorla and Allan M. Schiffman at EIT in 1994 [1] and published in 1999 as RFC 2660 Netscape's dominance of the browser market led to HTTPS becoming the de facto method for securing web communications.
S-HTTP encrypts only the served page data and submitted data like POST fields, leaving the initiation of the protocol unchanged. Because of this, S-HTTP could be used concurrently with HTTP (unsecured) on the same port, as the unencrypted header would determine whether the rest of the transmission is encrypted.
In contrast, HTTP over TLS wraps the entire communication within Transport Layer Security (TLS; formerly SSL), so the encryption starts before any protocol data is sent. This creates a name-based virtual hosting "chicken and egg" issue with determining which DNS name was intended for the request.
This means that HTTPS implementations without Server Name Indication (SNI) support require a separate IP address per DNS name, and all HTTPS implementations require a separate port (usually 443 vs. HTTP's standard 80) [2] for unambiguous use of encryption (treated in most browsers as a separate URI scheme, https://).
As documented in RFC 2817, HTTP can also be secured by implementing HTTP/1.1 Upgrade headers and upgrading to TLS. Running HTTP over TLS negotiated in this way does not have the implications of HTTPS with regards to name-based virtual hosting (no extra IP addresses, ports, or URI space). However, few implementations support this method.
In S-HTTP, the desired URL is not transmitted in the cleartext headers, but left blank; another set of headers is present inside the encrypted payload. In HTTP over TLS, all headers are inside the encrypted payload and the server application does not generally have the opportunity to gracefully recover from TLS fatal errors (including 'client certificate is untrusted' and 'client certificate is expired'). [2]
The Domain Name System (DNS) is a hierarchical and distributed name service that provides a naming system for computers, services, and other resources on the Internet or other Internet Protocol (IP) networks. It associates various information with domain names assigned to each of the associated entities. Most prominently, it translates readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols. The Domain Name System has been an essential component of the functionality of the Internet since 1985.
HTTP 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 a mouse click or by tapping the screen in a web browser.
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 Real-Time Streaming Protocol (RTSP) is an application-level network protocol designed for multiplexing and packetizing multimedia transport streams over a suitable transport protocol. RTSP is used in entertainment and communications systems to control streaming media servers. The protocol is used for establishing and controlling media sessions between endpoints. Clients of media servers issue commands such as play, record and pause, to facilitate real-time control of the media streaming from the server to a client or from a client to the server.
The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice, video and messaging applications. SIP is used in Internet telephony, in private IP telephone systems, as well as mobile phone calling over LTE (VoLTE).
In computing, Internet Protocol Security (IPsec) is a secure network protocol suite that authenticates and encrypts packets of data to provide secure encrypted communication between two computers over an Internet Protocol network. It is used in virtual private networks (VPNs).
An email client, email reader or, more formally, message user agent (MUA) or mail user agent is a computer program used to access and manage a user's email.
The File Transfer Protocol (FTP) is a standard communication protocol used for the transfer of computer files from a server to a client on a computer network. FTP is built on a client–server model architecture using separate control and data connections between the client and the server. FTP users may authenticate themselves with a plain-text sign-in protocol, normally in the form of a username and password, but can connect anonymously if the server is configured to allow it. For secure transmission that protects the username and password, and encrypts the content, FTP is often secured with SSL/TLS (FTPS) or replaced with SSH File Transfer Protocol (SFTP).
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network, such as the Internet. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible.
In the context of an HTTP transaction, basic access authentication is a method for an HTTP user agent to provide a user name and password when making a request. In basic HTTP authentication, a request contains a header field in the form of Authorization: Basic <credentials>, where <credentials> is the Base64 encoding of ID and password joined by a single colon :.
In computer networks, a tunneling protocol is a communication protocol which allows for the movement of data from one network to another. It can, for example, allow private network communications to be sent across a public network, or for one network protocol to be carried over an incompatible network, through a process called encapsulation.
Opportunistic encryption (OE) refers to any system that, when connecting to another system, attempts to encrypt communications channels, otherwise falling back to unencrypted communications. This method requires no pre-arrangement between the two systems.
Opportunistic TLS refers to extensions in plain text communication protocols, which offer a way to upgrade a plain text connection to an encrypted connection instead of using a separate port for encrypted communication. Several protocols use a command named "STARTTLS" for this purpose. It is a form of opportunistic encryption and is primarily intended as a countermeasure to passive monitoring.
Server Name Indication (SNI) is an extension to the Transport Layer Security (TLS) computer networking protocol by which a client indicates which hostname it is attempting to connect to at the start of the handshaking process. The extension allows a server to present one of multiple possible certificates on the same IP address and TCP port number and hence allows multiple secure (HTTPS) websites to be served by the same IP address without requiring all those sites to use the same certificate. It is the conceptual equivalent to HTTP/1.1 name-based virtual hosting, but for HTTPS. This also allows a proxy to forward client traffic to the right server during TLS/SSL handshake. The desired hostname is not encrypted in the original SNI extension, so an eavesdropper can see which site is being requested. The SNI extension was specified in 2003 in RFC 3546
WebSocket is a computer communications protocol, providing a simultaneous two-way communication channel over a single Transmission Control Protocol (TCP) connection. The WebSocket protocol was standardized by the IETF as RFC 6455 in 2011. The current specification allowing web applications to use this protocol is known as WebSockets. It is a living standard maintained by the WHATWG and a successor to The WebSocket API from the W3C.
The Upgrade header field is an HTTP header field introduced in HTTP/1.1. In the exchange, the client begins by making a cleartext request, which is later upgraded to a newer HTTP protocol version or switched to a different protocol. A connection upgrade must be requested by the client; if the server wants to enforce an upgrade it may send a 426 Upgrade Required response. The client can then send a new request with the appropriate upgrade headers while keeping the connection open.
HTTP/2 is a major revision of the HTTP network protocol used by the World Wide Web. It was derived from the earlier experimental SPDY protocol, originally developed by Google. HTTP/2 was developed by the HTTP Working Group of the Internet Engineering Task Force (IETF). HTTP/2 is the first new version of HTTP since HTTP/1.1, which was standardized in RFC 2068 in 1997. The Working Group presented HTTP/2 to the Internet Engineering Steering Group (IESG) for consideration as a Proposed Standard in December 2014, and IESG approved it to publish as Proposed Standard on February 17, 2015. The initial HTTP/2 specification was published as RFC 7540 on May 14, 2015.
DNS-based Authentication of Named Entities (DANE) is an Internet security protocol to allow X.509 digital certificates, commonly used for Transport Layer Security (TLS), to be bound to domain names using Domain Name System Security Extensions (DNSSEC).
DNS over HTTPS (DoH) is a protocol for performing remote Domain Name System (DNS) resolution via the HTTPS protocol. A goal of the method is to increase user privacy and security by preventing eavesdropping and manipulation of DNS data by man-in-the-middle attacks by using the HTTPS protocol to encrypt the data between the DoH client and the DoH-based DNS resolver. By March 2018, Google and the Mozilla Foundation had started testing versions of DNS over HTTPS. In February 2020, Firefox switched to DNS over HTTPS by default for users in the United States. In May 2020, Chrome switched to DNS over HTTPS by default.
DNS over TLS (DoT) is a network security protocol for encrypting and wrapping Domain Name System (DNS) queries and answers via the Transport Layer Security (TLS) protocol. The goal of the method is to increase user privacy and security by preventing eavesdropping and manipulation of DNS data via man-in-the-middle attacks. The well-known port number for DoT is 853.