PKLITE

Revision as of 16:55, 19 February 2022

PKLITE is an executable compression utility, from the makers of PKZIP (see ZIP). There was a free-for-noncommercial-use version, and a "Professional" version. There was a separate PKLITE32 product for 32-bit Windows.

It supports mainly DOS .EXE and .COM formats. Version 2.01 added the ability to compress Windows 3.x executables.

Many files compressed by PKLITE can be decompressed by PKLITE, using the -x option. The main exception is files compressed with -e, an option only available in the Professional version.

Identification

The PKLITE software includes CHK4LITE, a utility that tries to identify PKLITE-compressed files, and the version of PKLITE they were created with.

PKLITE-compressed files normally contain a copyright message near the beginning of the file (though this is not a very robust way to identify them). Based on limited testing, the message starts with either "PKLITE" or "PKlite". It is at offset 46 or 48 for COM files, 30 for DOS EXE files, 66 for Windows EXE files. Exception: COM files from v1.00β have "PK Copyr" at offset 38.

It's likely that all DOS EXE files made by v1.00 through v2.01 (though not the leaked v1.00β) have bytes 00 00 or 01 00 at offset 6, and 00 01 f0 ff at offset 20. This is fairly distinctive, though false positives are possible.

Technical notes

Version number

For pristine PKLITE-compressed EXE files, the 16-bit little-endian integer at offset 28 characterizes, in broad terms, the version of PKLITE that was used, and the type of compression. The low 12 bits are the version number; for example, 0x10f means version 1.15. The 0x1000 bit is set if "extra" compression was used. The 0x2000 bit is another compression setting.

Version 1.20

There was no free v1.20 release, but legitimate files do exist with that version number. Most of them are self-extracting ZIP files made by PKZIP v2.04's ZIP2EXE utility.

There is also a fake version that claims to be v1.20, but is actually a hacked copy of v1.12 Professional. The files it creates are (correctly) labeled as v1.12.

Specifications

• ModdingWiki: PKLite
• PKLITE V1.12 compression format

Software

• PKLITE freeware/shareware, for DOS
  • v1.00 1990-12-01: [1]
  • v1.03 1990-12-20: [2]
  • v1.05 1991-03-20: [3]
  • v1.12 1991-06-15: [4]
  • v1.13 1991-08-01: [5]
  • v1.14 1992-06-01: [6]
  • v1.15 1992-07-30: [7]
  • v1.50 1995-04-10: [8]
  • v2.01 1996-03-15: [9]
• PKLITE - other/various
  • PKLite at old-dos.ru - various versions
  • v1.00β 1990-05-29: [10] (not an authorized release[11])
  • fake v1.20 (1992-08-20): [12], [13], [14]

Static decompression:

• PKLITE (with -x option)
• depklite (Not a complete decompression utility, but maybe useful.)
• mz-explode
• Deark (with -m pklite option)

Dynamic decompression:

• DISLITE (notable because its source code was released)
  • v1.17a: [15], [16]
  • Source code
• A number of other DOS utilities exist to decompress PKLITE files; a few are at [17].

Protectors (utilities that modify a PKLITE-compressed file to make it more difficult to identify and/or decompress):

• PKFOOL v1.0 (requires BRUN45.EXE, not included)
• PKLTEFIX
• UN²PACK v2.0

Sample files

• https://github.com/camoto-project/testexe/tree/master/compress

Links

• Archived copy of PKLITE web page