WinRAR
WinRAR and the RAR file format have evolved over time. Support for the archive format RAR5, using the same RAR file extension as earlier versions, was added in version 5.0; the older RAR file format has since been referred to as RAR4. WinRAR versions before 5.0 do not support RAR5 archives; only older versions of WinRAR run on Windows versions prior to Windows Vista, and cannot open RAR5 archives. The RAR5 file format increased the maximum dictionary size to 1 GB; 11 different compression directory sizes from 1 MB to 1 GB are available, with the default in version 5 increased from 4 MB to 32 MB, typically improving compression ratio. AES encryption, when used, is in CBC mode and was increased in strength from 128- to 256-bit. Maximum path length for files in RAR and ZIP archives is increased to 2,048 characters. Options added in v5.0 include 256-bit BLAKE2 file-hashing algorithm instead of default 32-bit CRC32, duplicate file detection, NTFS hard and symbolic links, and Quick Open record to allow large archives to be opened faster. The RAR5 file format removed comments for each file (though archive comment still remains), authenticity verification, and specialized compression algorithms for text and multimedia files. RAR5 also changed the file name for split volumes from "archivename.rNN" to "archivename.partNN.rar". When creating RAR archives: The software is distributed as "try before you buy"; it may be used without charge for 40 days. When the period expires, the non-enterprise functionalities remain available, a move intended to discourage piracy. In China, a free-to-use personal edition has been provided officially since 2015. Although archiving with the RAR format is proprietary, RARLAB supplies as copyrighted freeware the C++ source code of the current UnRAR unpacker, with a license allowing it to be used in any software, thus enabling others to produce software capable of unpacking, but not creating, RAR archives. RAR for Android is free of charge. It displays advertisements; for a payment they can be disabled. A license for WinRAR does not provide ad-suppression for RAR for Android. In February 2019, a major security vulnerability in the unacev2.dll library which is used by WinRAR to decompress ACE archives was discovered. Consequently, WinRAR dropped the support for the ACE format from version 5.70. Self-extracting archives created with versions before 5.31 (including the executable installer of WinRAR itself) are vulnerable to DLL hijacking: they may load and use DLLs named UXTheme.dll, RichEd32.dll and RichEd20.dll if they are in the same folder as the executable file. It was widely reported that WinRAR v5.21 and earlier had a remote code execution (RCE) vulnerability which could allow a remote attacker to insert malicious code into a self-extracting executable (SFX) file being created by a user, "putting over 500 million users of the software at risk". However, examination of the claim revealed that, while the vulnerability existed, the result was merely an SFX which delivered its payload when executed; published responses dismissed the threat, one saying "If you can find suckers who will trust a .exe labelled as self-extracting archive ... then you can trick them into running your smuggled JavaScript". More recent versions do not support many older operating systems. Versions supporting older operating systems may still be available, but not maintained:
Security
WinRAR supports creating encrypted, multi-part and self-extracting archives.