Privacy-invasive software is computer software that ignores users’ privacy and, distributed with a specific intent of a commercial nature. Three typical examples of privacy-invasive software are adware and content hijacking programs. In a digital setting, such as the Internet, there are a wide variety of privacy threats; these vary from the tracking of user activity, to mass marketing based on the retrieval of personal information, to the distribution of information on lethal technologies used for, e.g. acts of terror. Today, software-based privacy-invasions occur in numerous aspects of Internet usage. Spyware programs set to collect and distribute user information secretly download and execute on users’ workstations. Adware displays advertisements and other commercial content based upon personal information retrieved by spyware programs. System monitors record various actions on computer systems. Keyloggers record users' keystrokes. Self-replicating malware spreads disorder in systems and networks.
Data-harvesting software programmed to gather e-mail addresses have become conventional features of the Internet, which among other things results in that spam e-mail messages fill networks and computers with unsolicited commercial content. With those threats in mind, we hereby define privacy-invasive software as: In this context, ignoring users’ right to be left alone means that the software is unsolicited and that it does not permit users to determine for themselves when, how and to what extent identifiable data is gathered, stored or processed by the software. Distributed means that it has entered the computer systems of users from servers placed on the Internet infrastructure. Of a commercial nature means that the software is used as a tool in some sort of a commercial plan to gain revenues. In early 2000, Steve Gibson formulated the first description of spyware after realizing software that stole his personal information had been installed on his computer, his definition reads as follows: This definition was valid in the beginning of the spyware evolution.
However, as the spyware concept evolved over the years it attracted new kinds of behaviours. As these behaviours grew both in number and in diversity, the term spyware became hollowed out; this evolution resulted in that a great number of synonyms sprang up, e.g. thiefware, scumware and badware. It is believed that the lack of a single standard definition of spyware depends on the diversity in all these different views on what should be included, or as Aaron Weiss put it: Despite this vague comprehension of the essence in spyware, all descriptions include two central aspects; the degree of associated user consent, the level of negative impact they impair on the user and their computer system. Because of the diffuse understanding in the spyware concept, recent attempts to define it have been forced into compromises; the Anti-Spyware Coalition, constituted by public interest groups, trade associations, anti-spyware companies, have come to the conclusion that the term spyware should be used at two different abstraction levels.
At the low level they use the following definition, similar to Steve Gibson's original one: However, since this definition does not capture all the different types of spyware available they provide a wider definition, more abstract in its appearance: Difficulties in defining spyware, forced the ASC to define what they call Spyware instead. This includes any software that does not have the users’ appropriate consent for running on their computers. Another group that has tried to define spyware is a group called StopBadware.org, which consists of actors such as Harvard Law School, Oxford University, Google and Sun Microsystems. Their result is that they do not use the term spyware at all, but instead introduce the term badware, their definition thereof span over seven pages, but the essence looks as follows: Both definitions from ASC and StopBadware.org show the difficulty with defining spyware. We therefore regard the term spyware at two different abstraction levels. On the lower level it can be defined according to Steve Gibsons original definition.
However, in its broader and in a more abstract sense the term spyware is hard to properly define, as concluded above. A joint conclusion is that it is important, for both software vendors and users, that a clear separation between acceptable and unacceptable software behaviour is established; the reason for this is the subjective nature of many spyware programs included, which result in inconsistencies between different users beliefs, i.e. what one user regards as legitimate software could be regarded as a spyware by others. As the spyware concept came to include more types of programs, the term got hollowed out, resulting in several synonyms, such as trackware and badware, all negatively emotive. We therefore choose to introduce the term privacy-invasive software to encapsulate all such software. We believe this term to be more descriptive than other synonyms without having as negative connotation. If we use the word invasive to describe such software, we believe that an invasion of privacy can be both desired and beneficial for the user as long as it is transparent, e.g. when implementing specially user-tailored services or when including personalization features in software.
The work by Warkentins et al. can be used as a starting point when developing a classifica
A computer worm is a standalone malware computer program that replicates itself in order to spread to other computers. It uses a computer network to spread itself, relying on security failures on the target computer to access it. Worms always cause at least some harm to the network if only by consuming bandwidth, whereas viruses always corrupt or modify files on a targeted computer. Many worms are designed only to spread, do not attempt to change the systems they pass through. However, as the Morris worm and Mydoom showed these "payload-free" worms can cause major disruption by increasing network traffic and other unintended effects; the actual term "worm" was first used in The Shockwave Rider. In that novel, Nichlas Haflinger designs and sets off a data-gathering worm in an act of revenge against the powerful men who run a national electronic information web that induces mass conformity. "You have the biggest-ever worm loose in the net, it automatically sabotages any attempt to monitor it...
There's never been a worm with that tough a head or that long a tail!"On November 2, 1988, Robert Tappan Morris, a Cornell University computer science graduate student, unleashed what became known as the Morris worm, disrupting a large number of computers on the Internet, guessed at the time to be one tenth of all those connected. During the Morris appeal process, the U. S. Court of Appeals estimated the cost of removing the virus from each installation at between $200 and $53,000. Morris himself became the first person tried and convicted under the 1986 Computer Fraud and Abuse Act. Any code designed to do more than spread the worm is referred to as the "payload". Typical malicious payloads might delete files on a host system, encrypt files in a ransomware attack, or exfiltrate data such as confidential documents or passwords; the most common payload for worms is to install a backdoor. This allows the computer to be remotely controlled by the worm author as a "zombie". Networks of such machines are referred to as botnets and are commonly used for a range of malicious purposes, including sending spam or performing DoS attacks.
Worms spread by exploiting vulnerabilities in operating systems. Vendors with security problems supply regular security updates, if these are installed to a machine the majority of worms are unable to spread to it. If a vulnerability is disclosed before the security patch released by the vendor, a zero-day attack is possible. Users need to be wary of opening unexpected email, should not run attached files or programs, or visit web sites that are linked to such emails. However, as with the ILOVEYOU worm, with the increased growth and efficiency of phishing attacks, it remains possible to trick the end-user into running malicious code. Anti-virus and anti-spyware software are helpful, but must be kept up-to-date with new pattern files at least every few days; the use of a firewall is recommended. In the April–June 2008 issue of IEEE Transactions on Dependable and Secure Computing, computer scientists described a new and effective way to combat internet worms; the researchers discovered how to contain worms that scanned the Internet randomly, looking for vulnerable hosts to infect.
They found that the key was to use software to monitor the number of scans that machines on a network send out. When a machine started to send out too many scans, it was a sign that it has been infected, which allowed administrators to take it off line and check it for malware. In addition, machine learning techniques can be used to detect new worms, by analyzing the behavior of the suspected computer. Users can minimize the threat posed by worms by keeping their computers' operating system and other software up to date, avoiding opening unrecognized or unexpected emails and running firewall and antivirus software. Mitigation techniques include: ACLs in routers and switches Packet-filters TCP Wrapper/ACL enabled network service daemons Nullroute Beginning with the first research into worms at Xerox PARC, there have been attempts to create useful worms; those worms allowed testing by John Shoch and Jon Hupp of the Ethernet principles on their network of Xerox Alto computers. The Nachi family of worms tried to download and install patches from Microsoft's website to fix vulnerabilities in the host system—by exploiting those same vulnerabilities.
In practice, although this may have made these systems more secure, it generated considerable network traffic, rebooted the machine in the course of patching it, did its work without the consent of the computer's owner or user. Regardless of their payload or their writers' intentions, most security experts regard all worms as malware. Several worms, like XSS worms, have been written to research. For example, the effects of changes in social activity or user behavior. One study proposed what seems to be the first computer worm that operates on the second layer of the OSI model, it utilizes topology information such as Content-addressable memory tables and Spanning Tree information stored in switches to propagate and probe for vulnerable nodes until the enterprise network is covered. Botnet Code Shikara Computer and network surveillance Computer virus Email spam Father Christmas Self-replicating machine Timeline of computer viruses and worms Trojan horse XSS worm Zombie Malware Guide – Guide for understanding and preventing worm infections on Vernalex.com.
"The'Worm' Programs – Early Experience with a Distributed Computation", John Shoch and Jon Hupp, Communications of the ACM, Volum
Computing is any activity that uses computers. It includes developing hardware and software, using computers to manage and process information and entertain. Computing is a critically important, integral component of modern industrial technology. Major computing disciplines include computer engineering, software engineering, computer science, information systems, information technology; the ACM Computing Curricula 2005 defined "computing" as follows: "In a general way, we can define computing to mean any goal-oriented activity requiring, benefiting from, or creating computers. Thus, computing includes designing and building hardware and software systems for a wide range of purposes; the list is endless, the possibilities are vast." and it defines five sub-disciplines of the computing field: computer science, computer engineering, information systems, information technology, software engineering. However, Computing Curricula 2005 recognizes that the meaning of "computing" depends on the context: Computing has other meanings that are more specific, based on the context in which the term is used.
For example, an information systems specialist will view computing somewhat differently from a software engineer. Regardless of the context, doing computing well can be complicated and difficult; because society needs people to do computing well, we must think of computing not only as a profession but as a discipline. The term "computing" has sometimes been narrowly defined, as in a 1989 ACM report on Computing as a Discipline: The discipline of computing is the systematic study of algorithmic processes that describe and transform information: their theory, design, efficiency and application; the fundamental question underlying all computing is "What can be automated?" The term "computing" is synonymous with counting and calculating. In earlier times, it was used in reference to the action performed by mechanical computing machines, before that, to human computers; the history of computing is longer than the history of computing hardware and modern computing technology and includes the history of methods intended for pen and paper or for chalk and slate, with or without the aid of tables.
Computing is intimately tied to the representation of numbers. But long before abstractions like the number arose, there were mathematical concepts to serve the purposes of civilization; these concepts include one-to-one correspondence, comparison to a standard, the 3-4-5 right triangle. The earliest known tool for use in computation was the abacus, it was thought to have been invented in Babylon circa 2400 BC, its original style of usage was by lines drawn in sand with pebbles. Abaci, of a more modern design, are still used as calculation tools today; this was the first known calculation aid - preceding Greek methods by 2,000 years. The first recorded idea of using digital electronics for computing was the 1931 paper "The Use of Thyratrons for High Speed Automatic Counting of Physical Phenomena" by C. E. Wynn-Williams. Claude Shannon's 1938 paper "A Symbolic Analysis of Relay and Switching Circuits" introduced the idea of using electronics for Boolean algebraic operations. A computer is a machine that manipulates data according to a set of instructions called a computer program.
The program has an executable form. The same program in its human-readable source code form, enables a programmer to study and develop a sequence of steps known as an algorithm; because the instructions can be carried out in different types of computers, a single set of source instructions converts to machine instructions according to the central processing unit type. The execution process carries out the instructions in a computer program. Instructions express, they trigger sequences of simple actions on the executing machine. Those actions produce effects according to the semantics of the instructions. Computer software or just "software", is a collection of computer programs and related data that provides the instructions for telling a computer what to do and how to do it. Software refers to one or more computer programs and data held in the storage of the computer for some purposes. In other words, software is a set of programs, procedures and its documentation concerned with the operation of a data processing system.
Program software performs the function of the program it implements, either by directly providing instructions to the computer hardware or by serving as input to another piece of software. The term was coined to contrast with the old term hardware. In contrast to hardware, software is intangible. Software is sometimes used in a more narrow sense, meaning application software only. Application software known as an "application" or an "app", is a computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with documents. Apps may be published separately; some users need never install one. Application software is contrasted with system software and middleware, which manage and integrate a computer's capabilities, but
A computer program is a collection of instructions that performs a specific task when executed by a computer. A computer requires programs to function. A computer program is written by a computer programmer in a programming language. From the program in its human-readable form of source code, a compiler can derive machine code—a form consisting of instructions that the computer can directly execute. Alternatively, a computer program may be executed with the aid of an interpreter. A collection of computer programs and related data are referred to as software. Computer programs may be categorized along functional lines, such as application software and system software; the underlying method used for some calculation or manipulation is known as an algorithm. The earliest programmable machines preceded the invention of the digital computer. In 1801, Joseph-Marie Jacquard devised a loom that would weave a pattern by following a series of perforated cards. Patterns could be repeated by arranging the cards.
In 1837, Charles Babbage was inspired by Jacquard's loom to attempt to build the Analytical Engine. The names of the components of the calculating device were borrowed from the textile industry. In the textile industry, yarn was brought from the store to be milled; the device would have had a "store"—memory to hold 1,000 numbers of 40 decimal digits each. Numbers from the "store" would have been transferred to the "mill", for processing, and a "thread" being the execution of programmed instructions by the device. It was programmed using two sets of perforated cards—one to direct the operation and the other for the input variables. However, after more than 17,000 pounds of the British government's money, the thousands of cogged wheels and gears never worked together. During a nine-month period in 1842–43, Ada Lovelace translated the memoir of Italian mathematician Luigi Menabrea; the memoir covered the Analytical Engine. The translation contained Note G which detailed a method for calculating Bernoulli numbers using the Analytical Engine.
This note is recognized by some historians as the world's first written computer program. In 1936, Alan Turing introduced the Universal Turing machine—a theoretical device that can model every computation that can be performed on a Turing complete computing machine, it is a finite-state machine. The machine can move the tape forth, changing its contents as it performs an algorithm; the machine starts in the initial state, goes through a sequence of steps, halts when it encounters the halt state. This machine is considered by some to be the origin of the stored-program computer—used by John von Neumann for the "Electronic Computing Instrument" that now bears the von Neumann architecture name; the Z3 computer, invented by Konrad Zuse in Germany, was a programmable computer. A digital computer uses electricity as the calculating component; the Z3 contained 2,400 relays to create the circuits. The circuits provided a floating-point, nine-instruction computer. Programming the Z3 was through a specially designed keyboard and punched tape.
The Electronic Numerical Integrator And Computer was a Turing complete, general-purpose computer that used 17,468 vacuum tubes to create the circuits. At its core, it was a series of Pascalines wired together, its 40 units weighed 30 tons, occupied 1,800 square feet, consumed $650 per hour in electricity when idle. It had 20 base-10 accumulators. Programming the ENIAC took up to two months. Three function tables needed to be rolled to fixed function panels. Function tables were connected to function panels using heavy black cables; each function table had 728 rotating knobs. Programming the ENIAC involved setting some of the 3,000 switches. Debugging a program took a week; the programmers of the ENIAC were women who were known collectively as the "ENIAC girls." The ENIAC featured parallel operations. Different sets of accumulators could work on different algorithms, it used punched card machines for input and output, it was controlled with a clock signal. It ran for eight years, calculating hydrogen bomb parameters, predicting weather patterns, producing firing tables to aim artillery guns.
The Manchester Baby was a stored-program computer. Programming transitioned away from setting dials. Only three bits of memory were available to store each instruction, so it was limited to eight instructions. 32 switches were available for programming. Computers manufactured; the computer program was written on paper for reference. An instruction was represented by a configuration of on/off settings. After setting the configuration, an execute button was pressed; this process was repeated. Computer programs were manually input via paper tape or punched cards. After the medium was loaded, the starting address was set via switches and the execute button pressed. In 1961, the Burroughs B5000 was built to be programmed in the ALGOL 60 language; the hardware featured circuits to ease the compile phase. In 1964, the IBM System/360 was a line of six computers each having the same instruction set architecture; the Model 30 was the least expensive. Customers could retain the same application software; each System/360 model featured multiprogramming.
With operating system support, multiple programs could be in memory at once. When one was waiting for input/output, another could compute; each model could emulate other computers. Customers could upgrade to the System/360 and ret
The Macintosh is a family of personal computers designed and sold by Apple Inc. since January 1984. The original Macintosh was the first mass-market personal computer that featured a graphical user interface, built-in screen and mouse. Apple sold the Macintosh alongside its popular Apple II family of computers for ten years before they were discontinued in 1993. Early Macintosh models were expensive, hindering its competitiveness in a market dominated by the Commodore 64 for consumers, as well as the IBM Personal Computer and its accompanying clone market for businesses. Macintosh systems still found success in education and desktop publishing and kept Apple as the second-largest PC manufacturer for the next decade. In the early 1990s, Apple introduced models such as the Macintosh LC II and Color Classic which were price-competitive with Wintel machines at the time. However, the introduction of Windows 3.1 and Intel's Pentium processor which beat the Motorola 68040 in most benchmarks took market share from Apple, by the end of 1994 Apple was relegated to third place as Compaq became the top PC manufacturer.
After the transition to the superior PowerPC-based Power Macintosh line in the mid-1990s, the falling prices of commodity PC components, poor inventory management with the Macintosh Performa, the release of Windows 95 saw the Macintosh user base decline. Prompted by the returning Steve Jobs' belief that the Macintosh line had become too complex, Apple consolidated nearly twenty models in mid-1997 down to four in mid-1999: The Power Macintosh G3, iMac, 14.1" PowerBook G3, 12" iBook. All four products were critically and commercially successful due to their high performance, competitive prices and aesthetic designs, helped return Apple to profitability. Around this time, Apple phased out the Macintosh name in favor of "Mac", a nickname, in common use since the development of the first model. Since their transition to Intel processors in 2006, the complete lineup is based on said processors and associated systems, its current lineup includes four desktops, three laptops. Its Xserve server was discontinued in 2011 in favor of the Mac Mac Pro.
Apple has developed a series of Macintosh operating systems. The first versions had no name but came to be known as the "Macintosh System Software" in 1988, "Mac OS" in 1997 with the release of Mac OS 7.6, retrospectively called "Classic Mac OS". In 2001, Apple released Mac OS X, a modern Unix-based operating system, rebranded to OS X in 2012, macOS in 2016; the current version is macOS Mojave, released on September 24, 2018. Intel-based Macs are capable of running non-Apple operating systems such as Linux, OpenBSD, Microsoft Windows with the aid of Boot Camp or third-party software. Apple produced a Unix-based operating system for the Macintosh called A/UX from 1988 to 1995, which resembled contemporary versions of the Macintosh system software. Apple does not license macOS for use on non-Apple computers, however System 7 was licensed to various companies through Apple's Macintosh clone program from 1995 to 1997. Only one company, UMAX Technologies was licensed to ship clones running Mac OS 8.
Since Apple's transition to Intel processors, there is a sizeable community around the world that specialises in hacking macOS to run on non-Apple computers, which are called "Hackintoshes". The Macintosh project began in 1979 when Jef Raskin, an Apple employee, envisioned an easy-to-use, low-cost computer for the average consumer, he wanted to name the computer after his favorite type of apple, the McIntosh, but the spelling was changed to "Macintosh" for legal reasons as the original was the same spelling as that used by McIntosh Laboratory, Inc. the audio equipment manufacturer. Steve Jobs requested that McIntosh Laboratory give Apple a release for the newly spelled name, thus allowing Apple to use it; the request was denied, forcing Apple to buy the rights to use this name. In 1978, Apple began to organize the Apple Lisa project, aiming to build a next-generation machine similar to an advanced Apple II or the yet-to-be-introduced IBM PC. In 1979, Steve Jobs learned of the advanced work on graphical user interfaces taking place at Xerox PARC.
He arranged for Apple engineers to be allowed to visit PARC to see the systems in action. The Apple Lisa project was redirected to utilize a GUI, which at that time was well beyond the state of the art for microprocessor capabilities. Things had changed with the introduction of the 32-bit Motorola 68000 in 1979, which offered at least an order of magnitude better performance than existing designs, made a software GUI machine a practical possibility; the basic layout of the Lisa was complete by 1982, at which point Jobs's continual suggestions for improvements led to him being kicked off the project. At the same time that the Lisa was becoming a GUI machine in 1979, Jef Raskin started the Macintosh project; the design at that time was for a easy-to-use machine for the average consumer. In
Scareware is a form of malware which uses social engineering to cause shock, anxiety, or the perception of a threat in order to manipulate users into buying unwanted software. Scareware is part of a class of malicious software that includes rogue security software and other scam software that tricks users into believing their computer is infected with a virus suggests that they download and pay for fake antivirus software to remove it; the virus is fictional and the software is non-functional or malware itself. According to the Anti-Phishing Working Group, the number of scareware packages in circulation rose from 2,850 to 9,287 in the second half of 2008. In the first half of 2009, the APWG identified a 585% increase in scareware programs; the "scareware" label can apply to any application or virus which pranks users with intent to cause anxiety or panic. Internet security writers use the term "scareware" to describe software products that produce frivolous and alarming warnings or threat notices, most for fictitious or useless commercial firewall and registry cleaner software.
This class of program tries to increase its perceived value by bombarding the user with constant warning messages that do not increase its effectiveness in any way. Software is packaged with a look and feel that mimics legitimate security software in order to deceive consumers; some websites display pop-up advertisement windows or banners with text such as: "Your computer may be infected with harmful spyware programs. Immediate removal may be required. To scan, click'Yes' below." These websites can go as far as saying that marriage would be at risk. Products using advertisements such as these are considered scareware. Serious scareware applications qualify as rogue software; some scareware is not affiliated with any other installed programs. A user can encounter a pop-up on a website indicating. In some scenarios, it is possible to become infected with scareware if the user attempts to cancel the notification; these popups are designed to look like they come from the user's operating system when they are a webpage.
A 2010 study by Google found 11,000 domains hosting fake anti-virus software, accounting for 50% of all malware delivered via internet advertising. Starting on March 29, 2011, more than 1.5 million web sites around the world have been infected by the LizaMoon SQL injection attack spread by scareware. Research by Google discovered that scareware was using some of its servers to check for internet connectivity; the data suggested. The company has placed a warning in the search results of users whose computers appear to be infected. Another example of scareware is Smart Fortress; this site scares people into thinking they have lots of viruses on their computer and asks them to buy the professional service. Some forms of spyware qualify as scareware because they change the user's desktop background, install icons in the computer's notification area, claiming that some kind of spyware has infected the user's computer and that the scareware application will help to remove the infection. In some cases, scareware trojans have replaced the desktop of the victim with large, yellow text reading "Warning!
You have spyware!" or a box containing similar text, have forced the screensaver to change to "bugs" crawling across the screen. Winwebsec is the term used to address the malware that attacks the users of Windows operating system and produces fake claims similar to that of genuine anti-malware software. SpySheriff exemplifies spyware and scareware: it purports to remove spyware, but is a piece of spyware itself accompanying SmitFraud infections. Other antispyware scareware may be promoted using a phishing scam. Another approach is to trick users into uninstalling legitimate antivirus software, such as Microsoft Security Essentials, or disabling their firewall. Since antivirus programs include protection against being tampered with or disabled by other software, scareware may use social engineering to convince the user to disable programs which would otherwise prevent the malware from working. In 2005, Microsoft and Washington state sued Secure Computer for $1 million over charges of using scareware pop-ups.
Washington's attorney general has brought lawsuits against Securelink Networks, High Falls Media, the makers of Quick Shield. In October 2008, Microsoft and the Washington attorney general filed a lawsuit against two Texas firms, Branch Software and Alpha Red, producers of the Registry Cleaner XP scareware; the lawsuit alleges that the company sent incessant pop-ups resembling system warnings to consumers' personal computers stating "CRITICAL ERROR MESSAGE! - REGISTRY DAMAGED AND CORRUPTED", before instructing users to visit a web site to download Registry Cleaner XP at a cost of $39.95. On December 2, 2008, the U. S. Federal Trade Commission filed a Complaint in federal court against Inc.. ByteHosting Internet Services, LLC, as well as individuals Sam Jain, Daniel Sundin, James Reno, Marc D’Souza, Kristy Ross; the Complaint listed Maurice D’Souza as a Relief Defendant, alleged that he held proceeds of wrongful conduct but not accusing him of violating any law. The FTC alleged that the other Defendants violated the FTC Act by deceptively marketing software, including WinFixer, WinAntivirus, DriveCleaner, ErrorSafe, XP Antivirus.
According to the complaint, the Defendants falsely represented that scans of a consumer's computer showed that it had been compromised or infected and offered to sell software to fix the alleged problems. Another type of scareware i
Electronic mail is a method of exchanging messages between people using electronic devices. Invented by Ray Tomlinson, email first entered limited use in the 1960s and by the mid-1970s had taken the form now recognized as email. Email operates across computer networks, which today is the Internet; some early email systems required the author and the recipient to both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward and store messages. Neither the users nor their computers are required to be online simultaneously. An ASCII text-only communications medium, Internet email was extended by Multipurpose Internet Mail Extensions to carry text in other character sets and multimedia content attachments. International email, with internationalized email addresses using UTF-8, has been standardized, but as of 2017 it has not been adopted; the history of modern Internet email services reaches back to the early ARPANET, with standards for encoding email messages published as early as 1973.
An email message sent in the early 1970s looks similar to a basic email sent today. Email had an important role in creating the Internet, the conversion from ARPANET to the Internet in the early 1980s produced the core of the current services; the term electronic mail was used generically for any electronic document transmission. For example, several writers in the early 1970s used the term to describe fax document transmission; as a result, it is difficult to find the first citation for the use of the term with the more specific meaning it has today. Electronic mail has been most called email or e-mail since around 1993, but variations of the spelling have been used: email is the most common form used online, is required by IETF Requests for Comments and working groups and by style guides; this spelling appears in most dictionaries. E-mail is the format that sometimes appears in edited, published American English and British English writing as reflected in the Corpus of Contemporary American English data, but is falling out of favor in some style guides.
Mail was the form used in the original protocol standard, RFC 524. The service is referred to as mail, a single piece of electronic mail is called a message. EMail is a traditional form, used in RFCs for the "Author's Address" and is expressly required "for historical reasons". E-mail is sometimes used, capitalizing the initial E as in similar abbreviations like E-piano, E-guitar, A-bomb, H-bomb. An Internet e-mail consists of an content. Computer-based mail and messaging became possible with the advent of time-sharing computers in the early 1960s, informal methods of using shared files to pass messages were soon expanded into the first mail systems. Most developers of early mainframes and minicomputers developed similar, but incompatible, mail applications. Over time, a complex web of gateways and routing systems linked many of them. Many US universities were part of the ARPANET, which aimed at software portability between its systems; that portability helped make the Simple Mail Transfer Protocol influential.
For a time in the late 1980s and early 1990s, it seemed that either a proprietary commercial system or the X.400 email system, part of the Government Open Systems Interconnection Profile, would predominate. However, once the final restrictions on carrying commercial traffic over the Internet ended in 1995, a combination of factors made the current Internet suite of SMTP, POP3 and IMAP email protocols the standard; the diagram to the right shows a typical sequence of events that takes place when sender Alice transmits a message using a mail user agent addressed to the email address of the recipient. The MUA formats the message in email format and uses the submission protocol, a profile of the Simple Mail Transfer Protocol, to send the message content to the local mail submission agent, in this case smtp.a.org. The MSA determines the destination address provided in the SMTP protocol, in this case email@example.com, a qualified domain address. The part before the @ sign is the local part of the address the username of the recipient, the part after the @ sign is a domain name.
The MSA resolves a domain name to determine the qualified domain name of the mail server in the Domain Name System. The DNS server for the domain b.org responds with any MX records listing the mail exchange servers for that domain, in this case mx.b.org, a message transfer agent server run by the recipient's ISP. smtp.a.org sends the message to mx.b.org using SMTP. This server may need to forward the message to other MTAs before the message reaches the final message delivery agent; the MDA delivers it to the mailbox of user bob. Bob's MUA picks up the message using either the Post Office Protocol or the Internet Message Access Protocol. In addition to this example and complications exist in the email system: Alice or Bob may use a client connected to a corporate email system, such as IBM Lotus Notes or Microsoft Exchange; these systems have their own internal email format and their clients communicate with the email server using a vendor-specific, proprietary protocol. The server sends or receives email via the Internet through the product's Internet mail gateway which does any necessary reformatt