Computer security is necessary to protect the computer and the data stored or accessible on it. Computers are used at work, in schools and for research. They also support critical business processes. Computers also protect personal and sensitive business information. The meaning of IT security has changed over the years. In the past, people didn't have to worry about someone putting a virus on their computer, the only problem they had then was someone taking it from them. There were viruses, but they were used for the mainframe and therefore did not work, not for personal computers. Even then, few personal computers were in use. Many people couldn't afford it in the past. Then there were people who didn't know what computers were and what they did. Today, no one knows what a computer is for. Today, most people have at least one computer of some kind in their home. In the business world, people would shut down computers in the computer room to prevent people from messing up the machine. The machines were too big to transport. The mainframes were massive machines that took up a lot of space. You didn't have to worry about someone moving them. Today, the size of computers is much smaller. These computers are portable and can therefore be taken with you but that is not the main problem. The main problem occurs when people steal data from your machine while you are surfing the Internet. All users want to prevent their computer from being stolen and the data stored on their computer from being stolen. Users do not want anyone to install viruses on their computer or anything that can harm the computer. Some companies will only allow strict middle of paper...... access to spyware or antivirus software. Also, these programs can remove malware and malware can be detected. Malware is any software activity that damages or blocks the activity of a service on a computer system. Types of malware are spyware, keyloggers, worms and Trojans. App permission is another element of app security. Application permission allows the software owner to only have rights to the application. There may be other uses that can enter data, but they cannot modify or delete the data. The programs are configured so that users who do not have permissions can use the programs but cannot make changes to them. Input validation is the process of validating data entered into a system. If data is not validated, there will be more errors in the output and erratic system behavior. When it's bad