PKZIP is a classic data compression software developed by Phil Katz and his company, PKWARE, Inc. , which essentially created the ZIP file format that became the industry standard.

: Every ZIP file contains a unique "record separator" marked with the initials "PK" as a tribute to Phil Katz.

: Katz distributed the ZIP standard for free, allowing any developer to write programs that could read and write the format.

The software traditionally consists of two main utilities, as detailed in IBM's usage guide :