368 Chapter 15 Digital Citizenship Copyright Goodheart-Willcox Co., Inc. an invitation to click on a website link for more information about an advertisement, as the link may trigger malware. One click can activate a code, and your computer could be hacked or infected. Malware comes in many forms including spyware, Trojan horses, worms, and viruses. Spyware is software that spies on a computer. Spyware can capture private information, such as e-mail messages, usernames, passwords, bank account information, and credit card information. Often, affected users are not aware that spyware is on their computer. Trojan horses are malware usually disguised to appear as a useful or common application in order to convince people to download and use the program. However, the Trojan horse performs malicious actions on the user’s computer, such as destroying data or stealing information. Trojan horses do not self-replicate, nor do they infect other fi les. Worms are similar to Trojan horses, except they do self-replicate. Worms self-replicate so they can infect other computers and devices. Like Trojan horses, worms do not infect other fi les. A software virus is a computer program designed to negatively impact a computer system by infecting other fi les. A virus may destroy data on the computer, cause programs to malfunction, bring harm to a network, or steal information. Viruses can be introduced to a computer in many ways, such as by downloading infected fi les from an e-mail or website. Virus-protection software helps safeguard a computer and should be used on any computer or electronic device that is connected to the Internet or any type of network. Virus- protection software is also referred to as antivirus or antimalware software. Virus-protection software should also have a fi rewall. A fi rewall is a program that monitors information coming into a computer. It helps ensure that only safe information gets through. Digital Security Do not be lulled into a false sense of security when communicating with others online. Be especially careful with those whom you do not know personally. Avoid opening e-mails that look suspicious. Use common sense when deciding what personal details you share, especially your address and Social Security number. Resist the urge to share too much information that could be stolen. Avoid Identity Theft Identity theft is an illegal act that involves stealing someone’s personal information and using that information to commit theft or fraud. There are many ways that your personal information can be stolen without your knowing. A lost credit card or driver’s license can provide thieves with the information they need to steal a person’s identity. Criminals also steal physical mail to commit identity theft. This method is often called dumpster diving. However, computer technology has made identity theft through digital means the most prevalent. Tips for protecting yourself from identity theft are listed in Figure 15-3.