DIGITAL SIGNATURE

We are all familiar with signatures. We have our own unique signatures which we use for various reasons. Such signatures are mainly used to identify us when doing some transactions somewhere. The same is true with digital signatures in this world of computing. But what really is a digital signature?

Wikipedia describes digital signature as a mathematical scheme for demonstrating the authenticity of a digital message or document.

The scheme of digital signatures is vital in a way that it assures you as a user of who the sender or writer of the document or piece of software is. Secondly, it proves that the document or software certificate is valid and not an expired one; which simply means that the the integrity of the document or software was not in any way modified after the signature. Thirdly, it assures that the document or software originated from a trusted source. It is good idea to verify the digital signature of the document or software you want to use. Windows XP or later Versions will warn you that the Software you are trying to install is not "digitally signed". When you see this warning, it simply tells you that the source cannot be trusted or the contents were tampered with after the digital signing. If you continue with your installation, you do so at your own risk.

Implementation of digital signature is based on asymmetric cryptography. Asymmetric Cryptography involves a pair of private and public keys used for encrypting or decrypting message or document in order to provide security up to its intended recipient.This enhances security of data by transforming text into unreadable form. It is the responsibility of the user to ensure secrecy of his private key which should not be accessed to by anyone else. The public key can be freely distributed to other users. It should be noted here that as a requirement, data messages encrypted using public key can be decrypted using the relevant private key. This is done to ensure that the sender is real and the integrity of the message can be trusted or the sender has truly signed it.