PKZIP
PKZIP is a compression program originally written by Phil Katz and marketed by his company PKWARE Inc. PKZIP is an abbreviation for P hil K atz ' ZIP program .
The first version of PKZIP appeared in 1989. It was a DOS command line program and was distributed as shareware with a registration fee of $ 25. PKZIP 1 used three different compression algorithms called shrinking , reducing and imploding , one of which was chosen based on the characteristics of the file to be compressed. Although these files were very common back then, files in the PKZIP-1 format are rarely found today, and many modern unzip programs are no longer able to deal with these compression methods.
In 1993 PKWARE released PKZIP 2. This version replaced the various compression methods of the first version with a single new method, which Katz called deflating . The resulting file format has since been ubiquitous on Microsoft Windows and on the Internet - almost all files with the .zip- filename extension are in PKZIP-2 format, and programs for reading and writing these files are available on all common platforms.
PKWARE continues to develop PKZIP, but newer versions of the PKZIP format incorporate proprietary compression techniques.
In addition, in 2004 PKWARE introduced a new line of products called SecureZIP . This is PKZIP + encryption with up to 256 bits according to the AES standard. The peculiarity of SecureZIP is that the entire block of data is encrypted and is backed not only by a password, there is also the possibility x.509 - Certificates to use.