User:Closeapple/info/Comparison of ZIP file archiver support
Archivers in the chart are chosen primarily by how widespread they have been; the chart can be used to get an idea of what features of ZIP files can be expected to be generally available. It is not intended to be a "me-too" list for every archiver available.
- Info-ZIP's Zip 1.1 was the last version to support creating Shrinking and Imploding, and is probably therefore the last easily-available program to do so.
- As of 2009[update], Info-ZIP's Zip 2.32 and UnZip 5.52 were the most widespread versions on most Linux distributions. Zip 2.32's man page explicitly says it supports only store (method 0) and deflate (method 8). Some binary distributions of UnZip 5.52 have USE_UNSHRINK (method 1) and USE_DEFLATE64 (method 9).
- Info-Zip's Zip 3.0 and UnZip 6.0 are the newest, but not as widespread yet. Both Zip 3.0 and UnZip 6.0 mention bzip2 (method 12) support in their new features lists.
- Windows Explorer:
- Windows has had native support for ZIP files since Windows Me, and support was also included in the Windows 98 Plus! pack. Windows 98 Plus! and Windows Me sometimes saves ZIP passwords in the clear to the file Dynazip.log in the main Windows directory.
- Windows 2000 does not have native support.
- Windows XP has support.
- Windows Vista and Windows Server 2008 can compress with Deflate64.
- Windows Vista and Windows 7 cannot decrypt ZIP files natively, even files encrypted with previous versions of Windows Explorer.
- WinZip is the software that first introduced compression methods 96 (12.0), 97 (11.0), and 98. As of 28 October 2009[update], the latest WinZip is 14.0 and the latest with new compression methods is 12.0 with LZMA and Compressed JPEG. 12.1 introduced the extension .zipx for ZIP files with nontraditional compression.
- The most important methods for widespread support are 8 then 0. As of 2009[update], far third might be 9.
- Method 0 (Store) is no compression, and is not listed in the chart.
- Methods 2–5 (Reduce) were probably only files created in 1989 by PKZIP prior to 1.01. Wikipedia PKZIP article implies that Reduce became decompress-only in PKZIP 1.01. Info-ZIP FTP site file claims: unreduce algorithm used in some early beta versions of PKZIP 2.0 and described in PKWARE's appnote.txt ... was never used in the "real" world
- Method 8 (DEFLATE) is the compression method used by every ZIP archiver since 1993; support for this method is, as a practical matter, mandatory for compatibility with other ZIP archivers and the majority of ZIP files publicly available.
- Method 10 (DCL Imploding) is sometimes referred to as "old IBM TERSE" in documentation, in contrast to method 18.
- Method 12 (bzip2) was introducted with PKZIP and SecureZIP 6.0.
- Method 18 (IBM TERSE) is sometimes referred to as "new IBM TERSE" in documentation, to distinguish from method 10.
- Method 96 (Compressed JPEG) is a recompression method first introducted in WinZip 12.
- Method 98 (PPMd Version I revision 1) is not supported as a writable format in ZIP by 7-Zip 4.65 despite PPMd being supported in 7-Zip's native 7z format. It is supported from 9.11 on.
Older software versions in this table are those historically significant to the coverage of ZIP support, and/or were the last of their kind to support one of the old Implode or Reduce methods.
|Info-UnZip 5.52u||Read||Non-free Patch||Read||No||Read||Read||No||No||No||No||No||No||No||No|
|Info-UnZip 6.0u||Read||Non-free Patch||Read||No||Read||Read||No||Read||No||No||No||No||No||No|
|Windows 98 Plus!|
- "Old" is the traditional ZIP password encryption from PKZIP 1 and 2; it is now considered easy to crack.
- "WZ-AE" is AE-1 and AE-2, the secure AES encryption method introduced in WinZip 9.0
- "SES-AES" is AES with the secure encryption method introduced in PKZIP/SecureZIP
- "Directory encryption" indicates Central Directory Encryption — the ability to encrypt the headers and directory information itself
|WinZip 9.0 Beta 3||Yes||Yes||Read||?|
|Windows 98 Plus!||Yes||No||No||?|
- ^a Ancient legacy version, but notable because of old features or effect on the ZIP format
- ^D Last version of this program available for MS-DOS
- ^u Unzips only: extracts files from ZIP archives only; does not modify.
- ^z Zips only: modifies ZIP archives only; does not extract.
- Pavlov, Igor (2010-11-02). "History of the 7-Zip". Retrieved 2010-11-11.
- "Description of Zip (.zip) Files (Q259177)". Microsoft. 2007-01-27. Retrieved 2009-10-28. Unknown parameter
- "Microsoft Security Bulletin (MS01-019): Passwords for Compressed Folders are Recoverable". Microsoft TechNet. Microsoft Corporation. 2003-06-23. Retrieved 2010-11-12.
- "Encrypted Compressed Folder Password Saved to Local File (Q265131)". Microsoft. 2007-01-27. Retrieved 2009-10-28. Unknown parameter
- "How to create and use compressed (zipped) folders in Windows XP (Q306531)". Microsoft. 2008-11-06. Retrieved 2009-10-28. Unknown parameter
- "Compressed folder becomes corrupted when larger than 2 gigabytes (Q301325)". Microsoft Knowledge Base. 3.0. Microsoft Corporation. May 14, 2009. Retrieved 2010-11-10.
In Windows Vista and in Windows Server 2008, compressed folders can be larger than 2 GB. The folders are compressed by the DEFLATE64 algorithm. However, the DEFLATE64 algorithm is not backward compatible with earlier versions of Microsoft Windows.
- GBorn (2010-02-01). "Password Protecting a zip folder in Windows 7". Microsoft Answers. Retrieved 2010-11-10.
- Info-ZIP un-reduce support requires a source code file that prohibits commercial use. See README.unreduce, dated 2001-01-13, in src/unred550.zip on the Info-ZIP FTP site. Retrieved 2009-10-28.
- "PKWare adds RSA Cryptography across Zip line" (Press release). PKWare. ComputerWire. 2003-01-26. Retrieved 2010-12-17.
- Encryption in PKZIP 1.x can be decrypted by later versions, but encryption by later versions cannot be decrypted by 1.x. In addition, later ZIP programs set the version field in ZIP files to "20" when encrypting, causing 1.1 to emit "PKUNZIP: Warning! I don't know how to handle" instead of attempting decryption. (If this is changed by modifying the ZIP data in place, 1.1 still claims the password is wrong on the file even when it is right.)
- Leyden, John (2004-01-21). "Zip file encryption compromise thrashed out". The Register. Retrieved 2010-12-17.
The latest beta of WinZip's software is able to read files wrapped up and encrypted using PKWare's PKZip.Links to whatsnew90.htm#beta3 (now dead link) as its own reference.
- "History of the 7-Zip" — 7-Zip history through current stable
- APPNOTE.TXT - .ZIP File Format Specification — PKWARE official ZIP specification
- Info-ZIP APPNOTE-IZ (ZIP format) — Info-ZIP official version ZIP specification, based on PKWARE APPNOTE 6.2.0 with extra commentary and edits
- APPNOTE.TXT 6.2.0 — version referenced by Microsoft Office Open XML Open Packaging Conventions (ECMA-376-2), but ECMA-376 does not support any compression method but 0 (Store) and 8 (Deflate), and does not support any encryption.