RAR stands for Roshal ARchive. It is a non-documented archive file format that supports data compression, error recovery, and file spanning. It was developed by a Russian software engineer, Eugene Roshal (the first letter of his surname contributing to the name of the archive format), and is currently licensed by win.rar GmbH.
An RAR file is a special computer file format that can store single or multiple documents and folders in a highly compressed form. The file can later be decompressed to extract the original documents and folders. It works like ZIP files do on Windows, and like Stuff-It files do on the Mac. RAR files are 'archives' which can contain one or more compressed files.
It enables users to compress all kinds of computer documents and folders and store them under a single RAR file. This compressed file could now be used as an archive for backup purposes. It could also be easily transferred to another computer through a floppy disk or over the Internet. Since the RAR format decreases the size of the file considerably, one needs lesser amount of disks or used lesser bandwidth on the Internet to transfer the compressed files. Once the files are transferred to the destination, they could then be decompressed to extract the original content intact.
Apart from these useful features the RAR format also has others that make it a versatile compression and archiving tool. For instance, it packs within its file format, chunks of data known as recovery records which help in restoring the original content even if the RAR file gets damaged during storage or transfer. It also uses AES or Advanced Encryption Standard which is a strong 128 bit encryption algorithm to protect the file. RAR further supports Unicode in order to store non-English filenames within its archive. This particular feature has made it popular in non-English speaking countries like Russia and others.