Poster for updating antivirus signatures
The work of von Neumann was later published as the "Theory of self-reproducing automata".In his essay von Neumann described how a computer program could be designed to reproduce itself.Infected computer programs can include, as well, data files, or the "boot" sector of the hard drive.When this replication succeeds, the affected areas are then said to be "infected" with a computer virus.
These systems require accurate and up-to-date signatures, and must operate in real time at high speeds.
So many researches have been done by students and experts over this widely used area.
Even companies have spent massive budgets for researches, in order to acquire new methods or find the searching algorithms which suits their purposes.
was an example of a virus which was not malicious software (malware), but was putatively benevolent (well-intentioned).
However, antivirus professionals do not accept the concept of "benevolent viruses", as any desired function can be implemented without involving a virus (automatic compression, for instance, is available under the Windows operating system at the choice of the user).
However, not all viruses carry a destructive "payload" and attempt to hide themselves—the defining characteristic of viruses is that they are self-replicating computer programs which modify other software without user consent.