Info-ZIP is a set of

open-source software Open-source software (OSS) is Software, computer software that is released under a Open-source license, license in which the copyright holder grants users the rights to use, study, change, and Software distribution, distribute the software an ...

to handle ZIP archives. It has been in circulation since 1989. It consists of 4 separately-installable packages: the Zip and UnZip command-line utilities; and WiZ and MacZip, which are

graphical user interface A graphical user interface, or GUI, is a form of user interface that allows user (computing), users to human–computer interaction, interact with electronic devices through Graphics, graphical icon (computing), icons and visual indicators such ...

s for archiving programs in

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

and

classic Mac OS Mac OS (originally System Software; retronym: Classic Mac OS) is the series of operating systems developed for the Mac (computer), Macintosh family of personal computers by Apple Computer, Inc. from 1984 to 2001, starting with System 1 and end ...

, respectively. Info-ZIP's Zip and UnZip have been

ported In software engineering, porting is the process of adapting software for the purpose of achieving some form of execution in a computing environment that is different from the one that a given program (meant for such execution) was originally desig ...

to dozens of

computing platform A computing platform, digital platform, or software platform is the infrastructure on which software is executed. While the individual components of a computing platform may be obfuscated under layers of abstraction, the ''summation of the requi ...

s. The UnZip web page describes UnZip as "The Third Most Portable Program in the World", surpassed by

Hello World Hello World may refer to: * "Hello, World!" program, a computer program that outputs or displays the message "Hello, World!" Music * "Hello World!" (composition), song by the Iamus computer * "Hello World" (Tremeloes song), 1969 * "Hello World" ...

, C-Kermit, and possibly the

Linux kernel The Linux kernel is a Free and open-source software, free and open source Unix-like kernel (operating system), kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the k ...

. The "zip" and "unzip" programs included with most Linux and Unix distributions are Info-ZIP's Zip and UnZip. In addition to the Info-ZIP releases themselves, parts of Info-ZIP, including

zlib zlib ( or "zeta-lib", ) is a software library used for data compression as well as a data format. zlib was written by Jean-loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compre ...

, have been used in numerous other

file archiver In computing, a file archiver is utility software that combines computer file, files into a single archive file or in less common cases, multiple files. A minimally designed archiver might concatenate the content of files along with file file n ...

s and other programs. Many Info-ZIP programmers have also been involved in other projects closely related to the DEFLATE compression algorithm, such as the PNG image format and the

software library.

Features

The UnZip package also includes three additional utilities: * fUnZip extracts a file in a ZIP or

gzip gzip is a file format and a software application used for file compression and decompression. The program was created by Jean-loup Gailly and Mark Adler as a free software replacement for the compress program used in early Unix systems, and ...

file directly to output from archives or other piped input. * UnZipSFX is software to make a ZIP file into an executable

self-extracting archive A self-extracting archive (SFX or SEA) is a computer executable program which combines compressed data in an archive file with machine-executable code to extract the information. Running on a compatible operating system, it does not need a ...

. * ZipInfo outputs, in a variety of formats, information about ZIP files and their contents. The Zip package includes three additional utilities: * ZipCloak adds or removes password encryption from file in a ZIP archive. * ZipNote allows the modification of comment fields in ZIP archives. * ZipSplit splits a ZIP archive into sections for separate disks or downloads.

History

UnZip

UnZip 1.0 (March 1989) was released by Samuel M. Smith. It was written in Pascal and C. Pascal was abandoned soon after. UnZip 2.0 (September 1989) was released by Samuel M. Smith. It included support for the "unimploding" (method 6) introduced by

PKZIP PKZIP is a file archiving computer program A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. It is one component of software, which also includes softwar ...

1.01. George Sipe created Unix version. UnZip 2.0a (December 1989) was released by Carl Mascott and John Cowan. In Spring 1990, Info-ZIP was formed as a

mailing list A mailing list is a collection of names and addresses used by an individual or an organization to send material to multiple recipients. Mailing lists are often rented or sold. If rented, the renter agrees to use the mailing list only at contra ...

on SIMTEL20, and released UnZip 3.0 (May 1990) became the first public release by Info-ZIP group. UnZip 4.0 (December 1990) adds support of "central directory" within .ZIP archive. UnZip 5.0 (August 1992) introduces support of DEFLATE (method 8) compression method, used in

1.93a. Method 8 has become the de facto base standard for ZIP archives. In 1994 and 1995 Info-ZIP turned a corner, and effectively became the ''de facto'' ZIP program on non-

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few op ...

systems. A huge number of ports were released that year, including numerous

minicomputer A minicomputer, or colloquially mini, is a type of general-purpose computer mostly developed from the mid-1960s, built significantly smaller and sold at a much lower price than mainframe computers . By 21st century-standards however, a mini is ...

mainframes A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise ...

and practically every

microcomputer A microcomputer is a small, relatively inexpensive computer having a central processing unit (CPU) made out of a microprocessor. The computer also includes memory and input/output (I/O) circuitry together mounted on a printed circuit board (P ...

ever developed. UnZip 5.41 (April 2000) was relicensed under Info-ZIP License. UnZip 5.50 (February 2002) adds support of Deflate64 (method 9) decompression. UnZip 6.0 adds support of "Zip64" .ZIP archive and bzip2 (method 12) decompression. Support for bzip2-style compression was also in Zip from 3.0f beta.

Zip

Zip 1.9 (August 1992) introduces support of DEFLATE (method 8) compression method. Method 8 has become the de facto base standard for ZIP archives. Zip 2.0 (September 1993) has many portability improvements. Zip 2.1 (May 1996) added new "UNIX" time info to preserve file times across timezones and OSes. Zip 2.3 (December 1999) was the first Info-ZIP archiver tool under the new BSD-like Info-ZIP License. Zip 3.0 (2008-07-07) supports "Zip64" .ZIP archive, more than 65536 files per archive, multi-part archive, bzip2 compression, Unicode (UTF-8) filename and (partial) comment, Unix 32-bit UIDs/GIDs

WiZ

WiZ 4.0 (November 1997) was released by Info-ZIP. WiZ 5.01 (April 2000) was relicensed under Info-ZIP License.

MacZip

MacZip 1.05 (July 2000) was released under Info-ZIP License. MacZip 1.06 was released in February 2001. It was written by Dirk Hasse.

Forks and patches

As a slowly-updated open software package, many patches have been written by various Linux distributions to improve info-zip tools. In addition, from 2015 to 2019, 14 unzip vulnerabilities have been published on the CVE list without version or website updates from info-zip. (Three CVEs from 2014 in oCERT-2014-011 are left out of most statistics; info-zip did provide patches on their now-defunct forum.)

Mark Adler Mark Adler (born 1959) is an American software engineer. He is best known for his work in the field of data compression as the author of the Adler-32 checksum function, and a co-author, together with Jean-loup Gailly, of the zlib compression lib ...

has a set of patches for unzip 6.0 that detects zip bombs of the overlapping type. This issue has a CVE ID of CVE-2019-13232. The Debian project provides various patches to correct typographical errors and security issues, including the 17 unzip CVEs. It also hardens against format string injection and other obvious security issues. To deal with pre-UTF-8 Zip files created on other

code pages In computing, a code page is a character encoding and as such it is a specific association of a set of printable character (computing), characters and control characters with unique numbers. Typically each number represents the binary value in a s ...

, Giovanni Scafora created a patch that hooks unzip up with

iconv In Unix and Unix-like operating systems, iconv (an abbreviation of internationalization conversion) is a command-line program and a standardized application programming interface (API) used to convert between different character encodings. "It ...

for encoding conversion. A version of the patch combined with CVE mitigations are provided as a User Package in Arch Linux. The Gentoo project improves upon the hard-coded locales with an external library. Similar approach for Ubuntu is being discussed. The Fedora project (an upstream of

Red Hat Enterprise Linux Red Hat Enterprise Linux (RHEL) is a commercial Linux distribution developed by Red Hat. Red Hat Enterprise Linux is released in server versions for x86-64, Power ISA, ARM64, and IBM Z and a desktop version for x86-64. Fedora Linux and ...

) applies Adler's patch, most of the Debian patches (or similar), as well as extra security patches like a stack non-execution patch to their unzip. The zip patches are similar to Debian patches.

Official betas

Some official improvements to zip and unzip are stuck in beta-stage as zip 3.1c and unzip 6.10b from 2015. Among other things, both added support for PPMd8 and LZMA compressions in files, support for AES encryption, and included iconv-based Unicode improvements (based on unzip-iconv). A newer release candidate, Zip 3.1d, appeared on the official FTP site in 2015, but the SourceForge page was not updated. Partially due to the added compressors, the zipped file size increased from 1.4 MB (3.1c) to 2.9 MB (3.1d). The antinode.info FTP site seems to be hosting an even more cutting-edge source of info-zip utilities. Individual revisions are organized into folders containing files differing from the previous revision, and zip archives for sources are occasionally released. , the site provides Unzip 6.10c (rev. 25, 21 Dec 2018) and a loose-file development version of Zip 3.1e (rev. 21, 14 Dec 2021). The owner of the site, Steven Schweda, maintains these versions. Schweda is a member of the original info-zip team.

Replacements

FreeBSD FreeBSD is a free-software Unix-like operating system descended from the Berkeley Software Distribution (BSD). The first version was released in 1993 developed from 386BSD, one of the first fully functional and free Unix clones on affordable ...

has opted to replace info-zip utilities. It produces a command-line compatible version of based on

libarchive libarchive is a free and open-source library for reading and writing various archive and compression formats. It is written in C and works on most Unix-like systems and Windows. History libarchive's development was started in 2003 as part of ...

, which also supports zipx and AES.

References

External links

*
Official (legacy) FTP siteSourceforge Patch submissions
{{FLOSS 1989 software Cross-platform free software File archivers Free data compression software Unix archivers and compression-related utilities Software using the BSD license