File extension
.rar
RAR 2.00 Format
.rar files are RAR archives: a proprietary compressed archive format known for strong compression, solid archives, recovery records, multi-volume splitting, and AES encryption.
Known meanings
Formats and reference material for .rar
Details
Format notes
RAR Archive
RAR is a proprietary archive format created by Eugene Roshal (the name stands for
“Roshal Archive”). It bundles files with compression and is valued for high
compression ratios and a set of robustness features aimed at reliable storage
and distribution of large data sets. The format is proprietary: the WinRAR/RAR
tools that create archives are commercial, while a freely redistributable
unrar decoder is provided so archives can be extracted broadly.
RAR supports “solid” archives that compress many files as one stream for better ratios, optional recovery records and recovery volumes that can repair or reconstruct damaged data, splitting an archive across multiple numbered volumes, strong AES encryption of data and optionally file names, and Unicode names.
Format Versions
There are two major on-disk formats. The older RAR4 format (signature
Rar!\x1a\x07\x00) is widely compatible, while RAR5 (Rar!\x1a\x07\x01\x00)
adds stronger encryption, larger dictionaries, and other improvements but is not
readable by pre-5.0 tools. Software should detect the version from the signature
rather than assume from the extension.
Preservation And Security Notes
Because creation is proprietary, RAR is a less common choice for long-term
archiving than open formats such as ZIP, 7z, or tar; migrating important content
to an open format is often advisable. The common media type is
application/vnd.rar. As with any archive, extractors handling untrusted RAR
files should guard against path traversal, decompression bombs, and archives
that rely on encryption to conceal contents.
Further Reading
- RARLAB (WinRAR / RAR):
https://www.rarlab.com/