Frederick B. Cohen (born 1956) is an American computer scientist and best known as the inventor of computer virus defense techniques.A short biography He gave the definition of "computer virus". Cohen is best known for his pioneering work on computer viruses, the invention of high-integrity operating system mechanisms now in widespread use, and automation of protection management functions.

In 1983, while a student at the University of Southern California's School of Engineering, he wrote a program for a parasitic application that seized control of computer operations, one of the first computer viruses, in Leonard Adleman’s class. He wrote a short program, as an experiment, that could "infect" computers, make copies of itself, and spread from one machine to another. It was hidden inside a larger, legitimate program, which was loaded into a computer on a floppy disk.

One of the few solid theoretical results in the study of computer viruses is Cohen's 1987 demonstration that there is no algorithm that can perfectly detect all possible viruses.An Undetectable Computer Virus (academic paper)

Cohen also believed there are positive viruses and he had created one called the compression virus which spreading would infect all executable files on a computer, not to destroy, but to make them smaller.Burger, Ralph, 1991. Computer Viruses and Data Protection, pp. 19-20

During the past 10 years of his research work, Fred Cohen wrote over 60 professional publications and 11 books.

Papers 1991, Trends In Computer Virus Research 1991, A Case for Benevolent Viruses 1991, The Computer Security Encyclopedia - Computer Viruses 1992, A Formal Definition of Computer Worms and Some Related Results 1989, Models of Practical Defenses Against Computer Viruses 1988, On the Implications of Computer Viruses and Methods of Defense 1984, Computer Viruses - Theory and Experiments 1989, Models of Practical Defenses Against Computer Viruses

References

Cohen, F., 1987. "Computer Viruses Theory and Experiments," Computers and Security, vol. 6, pp. 22--35.