ZIP is a popular, widespread file format for compressing and archiving data. A ZIP compressed file contains one or more files that have been compressed to reduce the size of stored data. The ZIP format uses a 32-bit CRC algorithm and includes two copies of the directory structure of the archive to provide greater protection against data loss. ZIP format was created in 1989 by Phil Katz for PKZIP program, but nowadays it works with many other programs. By the end of the nineties ZIP format has been integrated into its own interface supporting more and more file managers. Since 2002, all extended operating systems support ZIP file, which is represented as a directory (folder), and allows the transfer of similar files. Microsoft® has included built-in ZIP support ("compressed folders") in versions of its Windows® operating system since 1998. Apple® has included built-in ZIP support in Mac OS® X 10.3 and later, along with other compression formats.
A zombie computer, or zombie, is a computer connected to the Internet that has been infiltrated and compromised by a hacker, virus, or trojan. A zombie is only one of many in a botnet, used to perform malicious tasks under remote control. Most zombie owners are unaware that their computer is being used in this manner.