RAR

RAR file is a file format which creates file archives to support efficient data transfer. RAR file support data compression, file recovery and file spanning. RAR stands for Roshal archive, named after the Russian software engineer Eugene Roshal. It is currently licensed under Win.RAR GmbH. A RAR file uses the .rar file extension for data archives and the .rev file extension for recovery archives.

Source: “CHIP intelligent computing”, Sep 27 2006
Alternative Source: “http://www.chip.in”

Digital Signature

A digital signature is an encoded signage which is used instead of an actual handwritten signature. It provides authenticity and security to a message in an online document. A message can be any kind of data: an electronic mail, a contract, an online form, etc. You can also add a digital signature to messages encoded with protocols that are more complicated. digital signatures are mainly useful for programs on the internet which transfer data local machine requiring to conform its identity to conform its identity to any third party concern.

Source: “CHIP intelligent computing”, Sep 27 2006
Alternative Source: “http://www.chip.in”