#Rar format archive
#Rar format rar
#Rar format zip

#Rar format rar

RAR is a proprietary file format created solely by the compression software WinRAR.

#Rar format zip

better data compression rate than ZIP and uses a lossless compression.

#Rar format archive

The full specification is not publicly available but file structure information for RAR5 is available through the RARLab website.Īccording to one report, RAR format has gained much popularity over these years as compared to its competitor archive formats like 7Z, zip, etc. Proprietary format with limited public information. RAR files have appeared in various personal papers collections as a submission format for large PST email files. Often described as the basis for subsequent versions but no detailed information available. The End of Archive Marker follows the last File Header to close out the archive block, after which RAR does not read anything to permit third party tools to add extra information such as a digital signature to archive. Service headers: Optional headers that store supplementary information.If another hash algorithm is used, it is stored in the extra area record. File header: Includes among other data the Compression Record (stored as values 0 - 5 where 0 means no compression) and an optional Hash record for the standard CRC32 checksum.File headers are followed by optional Service headers. Main archive header which, among other things, includes the optional Locator tag to quickly access the positions of different service blocks without scanning the entire archive.Īfter the main archive header but still within the archive block comes one or more file headers, one for each file within the archive.Encryption version is declared in the tag of the same name with only AES-256 (value = 0) supported for RAR5. Size of encrypted header data block is aligned to 16 byte boundary. Every next header after this one is started from 16 byte AES-256 initialization vector followed by encrypted header data. Archive encryption header (optional): Present only in archives with encrypted headers.According to the ad hoc description at RARLab and to PRONOM, the file signatures for RAR2.0, RAR3, RAR4, and RAR5 all begin with 'Rar!' (Hex: 52 61 72 21). The RAR file signature is specific to the version of the format and must be searched for from the beginning of the file past the maximum SFX module size.Self-extracting module (optional): Also known as SFX, this means any data preceding the file signature and the block size and contents are not defined.The archive block is the most complex because it contains the headers for the archive itself as well as the file headers: The order of theseīlocks may vary, but the first block must be a marker block followed byĪn archive header block. At its core, a RAR file is comprised of a marker or introductory block, an archive block which includes the archive header and file header, and closing block which includes additional comments or other information needed to correctly process the file. The precise composition of the blocks evolved over time with the versions. Structurally, a RAR file is comprised of variable length blocks of required and optional data. RAR files are the native format for WinRAR software and can only be created through this tool which is licensed to win.rar GmbH although there are several options to open RAR files. RAR is a proprietary format under copyright, along with RAR's compression applications and libraries to Alexander Roshal, brother of Eugene Roshal. Similar in purpose to ZIP files, RAR files are data containers in which one or more files are stored in compressed form. See Relationships below for more details.

The current version as of this writing is RAR5. RAR4 is also known as RAR version 2.9 in some documentation. The early versions RAR1.3 and especially RAR1.5 are thought to be the base for later versions but no public documentation is available about these early versions. There are at least six main versions and subversions of the RAR format and because the early versions have little formal documentation, only selected versions currently are described at this site. RAR, or the Roshal ARchive format thanks to its namesake creator software developer Eugene Roshal, is a proprietary archive file format that supports data compression, error recovery and file spanning.