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

, 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 compressi ...

WinAce

WinAce, maintained by e-merge GmbH, is used to compress and decompress ACE files under

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 ...

. When installed, it lets the user choose between paying for a registration or installing WhenU SaveNow

adware Adware, often called advertising-supported software by its developers, is software that generates revenue by automatically displaying Online advertising, online advertisements in the user interface or on a screen presented during the installatio ...

. e-merge GmbH also produces a Commandline ACE for DOS; and a freeware

command-line interface A command-line interface (CLI) is a means of interacting with software via command (computing), commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user ...

decompression tool for

Linux Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

(

i386 The Intel 386, originally released as the 80386 and later renamed i386, is the third-generation x86 architecture microprocessor from Intel. It was the first 32-bit processor in the line, making it a significant evolution in the x86 archite ...

) and

macOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac computers. With ...

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 Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...

free software Free software, libre software, libreware sometimes known as freedom-respecting software is computer software distributed open-source license, under terms that allow users to run the software for any purpose as well as to study, change, distribut ...

. 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 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

source available Source-available software is software released through a source code distribution model that includes arrangements where the source can be viewed, and in some cases modified, but without necessarily meeting the criteria to be called ''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 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 Malware (a portmanteau of ''malicious software'')Tahir, R. (2018)A study on malware and malware detection techniques . ''International Journal of Education and Management Engineering'', ''8''(2), 20. is any software intentionally designed to caus ...

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 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, 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 integrity of archive ...

and other archiving products. Since WinACE support is discontinued, 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.

References

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
{{DEFAULTSORT:Ace (File Format) Archive formats