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A file compression and archiver utility for MS-DOS and Microsoft Windows from PKWARE, Inc.. PKZIP uses a variation on the sliding window compression algorithm. It comes with pkunzip and pklite and is available as shareware from most FTP archives in a self-expanding MS-DOS executable.

Current versions as of 1999-10-07: PKZIP 2.60 GUI for Microsoft Windows 3.1x, Windows 9x, Windows NT; PKZIP 2.50 Command Line for Windows 9x NT; PKZIP 2.04g for MS-DOS; PKZIP 2.51 for Unix, (Linux, SPARC Solaris, Digital, HP-UX, IBM AIX and SCO Unix); PKZIP 2.50 for OS/2; PKZIP for Open VMS/VAX.

WINZIP is a version with a GUI for Microsoft Windows.

A distribution in about 1995-06-22 claiming to be "PKZIP 3" was actually a trojan horse which attempted to reformat the hard disk and delete all files on it.

This article is provided by FOLDOC - Free Online Dictionary of Computing (

PK software

A family of compression utilities for DOS, Windows, OS/2, OpenVMS and Unix from PKWARE Inc., Milwaukee, WI ( In 1986, Phil Katz (the PK in PKWARE) developed the ZIP standard that is widely used throughout the world. Originally developed as DOS command line programs, third parties developed graphics-based products that supported the format. Later, PKWARE introduced a Windows version. PKARC and PKXARC were previous compression programs that are no longer supported.

Various Utilities
The PK utilities provide the following functions. PKZIP compresses, and PKUNZIP decompresses. PKSFX and ZIP2EXE create self-extracting archives that automatically decompress when they are run. PKLITE compresses only .EXE and .COM files, which, when run, automatically decompress first. Compression libraries are also available for developers.

In 2001, the ZIP file format was extended to include authentication and encryption features to make ZIP archives secure. Soon after, the company introduced its server-based SecureZIP product family to address the industry-need for not only compression but the secure transfer of data. Another major product was added in 2006; PartnerLink addresses the need to exchange data securely with external business partners.

A Short Career
In 2000, founder Phil Katz, a computer genius who battled many personal problems, died at the young age of 37. He left behind a multimillion-dollar company and one of the most influential pieces of software ever invented for mainstream PC users. See PKZIP abc's, PKZIP cross platform and SecureZIP.

A Zipped Example
The WinZip utility is widely used to compress files using PKZIP. Zipped files are lossless and are restored to their original format bit for bit when decompressed. This example highlights the file size difference. See lossless compression.
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References in periodicals archive ?
TI PKWARE DEBUTS PKZIP AND SECUREZIP FOR SYSTEM Z LINUX >TX PKWARE, Inc., Milwaukee, a leading provider of data-centric security and compression software, has introduced their PKZIP and SecureZIP products for Linux on the System z operating platform.
TELECOMWORLDWIRE-September 30, 2010-PKWARE releases new version of PKZIP and SecureZIP for z/OS on System z(C)1994-2010 M2 COMMUNICATIONS
WORLDWIDE COMPUTER PRODUCTS NEWS-September 30, 2010-PKWARE releases new version of PKZIP and SecureZIP for z/OS on System z(C)1995-2010 M2 COMMUNICATIONS
Today, SecureZIP and PKZIP are used by over 200 government agencies and 30,000 corporate entities, including 90% of the Fortune 100.
Compression/Decompression performance of up to 6Gbps for GZIP, PKZIP and variant protocols with unmatched compression ratios.
"We have been working with Lufthansa Systems since 2000, initially with our PKZIP data compression solutions, which were operating within their data center.
PKzip and WinZIP, commercial implementations of LZW, replace each 11-character string compression with a dictionary pointer to an earlier use of the word compression.
Developers can now integrate the company's PKZIP data compression and SecureZIP data security technologies into their custom applications and packaged software products.
PKWARE, Inc., a provider of trusted ZIP Solutions for the Enterprise, has announced enhancements to its award-winning PKZIP product for Windows.
It compacts the files you want to store into the most common, and proven, compression format--compatible with WinZip and PkZip. Both can be added to run natively within Windows; so that eliminates the problem of proprietary compression software.
The company will today announce that it has segmented its Windows software into two flavors, SecureZIP and PKZip. Previously, SecureZip was just the name of the RSA-based technology PKZip uses to encrypt Zip files.