Sustainability of Digital Formats: Planning for Library of Congress Collections

Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact
Format Description Categories >> Browse Alphabetical List

RAR Archive File Format, Version 3

>> Back
Table of Contents
Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name RAR Archive File Format, Version 3
Description

Roshal ARchive format version 3 (RAR3) is said to be built off RAR1.5 but there is no publicly available information for RAR1.5 to compare it to. Comments welcome. Structurally, RAR3 is comprised of a marker block, archive header and file header(s). These can be augmented as needed with optional comment headers, extra information blocks and subblocks. RAR3 declares a new block type, authenticity information, that was not present in RAR2. See RAR_Family for details on the file structure.

A key feature of RAR3 is the switch from proprietary and not open compression algorithms to PPMII and Lempel-Ziv (LZSS) algorithms. Wikipedia states that "encryption now uses cipher block chaining (CBC) instead of Advanced Encryption Standard (AES)" but documentation from WinRAR declares AES for RAR4 and RAR5.

Production phase See RAR_Family
Relationship to other formats
    Subtype of RAR_Family, RAR Archive File Format Family
    Has earlier version RAR2, RAR Archive File Format, Version 2
    Has later version RAR4, RAR Archive File Format, Version 4

Local use Explanation of format description terms

LC experience or existing holdings See RAR_Family.
LC preference None

Sustainability factors Explanation of format description terms

Disclosure See RAR_Family
    Documentation See RAR_Family
Adoption See RAR_Family
    Licensing and patents See RAR_Family
Transparency See RAR_Family
Self-documentation See RAR_Family
External dependencies See RAR_Family
Technical protection considerations See RAR_Family

Quality and functionality factors Explanation of format description terms

Other
Bundling/compression See RAR_Family

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension See note.  See RAR_Family
Internet Media Type See note.  See RAR_Family
File signature Hex: 52 61 72 21 1A 07 00
ASCII: Rar!
Wikipedia states that this magic number is applicable for RAR1.5 - RAR4 although Gary Kessler's File Signature Table and RAR 5.0 archive format tech note only specifically list this magic number for RAR4, not earlier versions. Acritum Software's description of RAR version 3.93 (not described at this site) lists this value for all versions since RAR1.5.
Pronom PUID See note.  No PUID as of March 2017.
Wikidata Title ID See note.  See RAR_Family.

Notes Explanation of format description terms

General See RAR_Family.
History See RAR_Family.

Format specifications Explanation of format description terms


Useful references

URLs


Last Updated: Friday, 21-Apr-2017 09:36:35 EDT