computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...

, ACE is a proprietary

data compression In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compressio ...

archive file format developed by Marcel Lemke, and later bought by e-merge GmbH. The peak of its popularity was 1999–2001, when it provided slightly better compression rates than RAR, which has since become more popular.

WinAce

WinAce WinAce is a legacy archiving app for Windows. It works primarily with the eponymous ACE archive format but supports ZIP, RAR and CAB. The app is not free, but its developer also developed a freeware, CLI app called Unace for macOS and Linux tha ...

, maintained by e-merge GmbH, is used to compress and decompress ACE files under Microsoft Windows. When installed, it lets the user choose between paying for a registration or installing

WhenU SaveNow WhenU Save/SaveNow (commonly referred to simply as WhenU or SaveNow), developed by the company WhenU, is a piece of advertising software generally considered to be adware or spyware. The program delivers advertisements, compares shopping results a ...

adware Adware, often called advertising-supported software by its developers, is software that generates revenue for its developer by automatically generating online advertisements in the user interface of the software or on a screen presented to the ...

. e-merge GmbH also produces a Commandline ACE for DOS; and a freeware command-line interface decompression tool for

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

(

i386 The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistors macOS macOS (; previously OS X and originally Mac OS X) is a Unix operating system developed and marketed by Apple Inc. since 2001. It is the primary operating system for Apple's Mac computers. Within the market of desktop and lapt ...

called "Unace". e-merge GmbH also provides several libraries for developers, including a freeware decompression DLL called "unace.dll". Some third-party archivers can read the format using this DLL. None of the above is open source

free software Free software or libre software is computer software distributed under terms that allow users to run the software for any purpose as well as to study, change, and distribute it and any adapted versions. Free software is a matter of liberty, no ...

. On November 23, 2007, version 2.69 of WinACE was released, including a less-intrusive

application, MeMedia AdVantage, which replaces WhenU. No other major changes are in this release.

Other implementations

An older version of an Unace 1.2b is

and licensed under the

GPL The GNU General Public License (GNU GPL or simply GPL) is a series of widely used free software licenses that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general u ...

by the author Marcel Lemke, but it cannot extract ACE archives from version 2.0 and newer. A newer version of Unace 2.5 that supports ACE 2.0 archives is available under a restrictive open source license, also by Marcel Lemke. An older, independent C implementation is part of XAD-Master libxad by Dirk Stöcker. It is limited to unpacking ACE 1.0 archives. Since 2017, there is a BSD licensed

python Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (pro ...

module and

CLI CLI may refer to: Computing * Call Level Interface, an SQL database management API * Command-line interface, of a computer program * Command-line interpreter or command language interpreter; see List of command-line interpreters * CLI (x86 instruc ...

utility by Daniel Roethlisberger, that supports unpacking of ACE 2.0 format archives.

Third-party support

''Packing'' of ACE files is licensed as proprietary information and only available through WinACE, while ''unpacking'' of ACE files is supported by a number of third-party archivers. However, virtually all of them (the ones that support ACE 2.x format) do this by using the proprietary "unace.dll" from e-merge GmbH.

Use for malware distribution

Since at least 2015, ACE archives have been used to deliver malware to victims by e-mail. This tactic was viable because popular archiving software was able to uncompress ACE archives, but support for the ACE format in security products such as mail filters, web content filters and

anti-virus software Antivirus software (abbreviated to AV software), also known as anti-malware, is a computer program used to prevent, detect, and remove malware. Antivirus software was originally developed to detect and remove computer viruses, hence the name. ...

was generally weak.

Security vulnerabilities

In February 2019 several major security vulnerabilities were found in the unacev2.dll library which is used by

WinRAR WinRAR is a trialware file archiver utility for Windows, developed by Eugene Roshal of win.rar GmbH. It can create and view archives in RAR or ZIP file formats, and unpack numerous archive file formats. To enable the user to test the integrit ...

and other archiving products. Since WinACE is

abandonware Abandonware is a product, typically software, ignored by its owner and manufacturer, and for which no official support is available. Within an intellectual rights contextual background, abandonware is a software (or hardware) sub-case of the ...

, users are advised against opening ACE archives in WinRAR and possibly other products using this library. WinRAR stopped supporting ACE as of version 5.70, and similar products are following suit.

External links

Official Website - Web Archive Snapshot from 14.07.2017

Download link for last Version 2.69i - Web Archive Snapshot from 21.01.2011

References

{{DEFAULTSORT:Ace (File Format) Archive formats