Introduction to Digital Signatures

The Process & Validity behind Digital Signature Technology.

Public Key Infrastructure – PKI

A cryptographic system that uses two keys, a public key known to everyone and a private key, the private key has full control to the key owner, and has to keep in secured environment. A unique element to the public key system is that the public and private keys are related in such a way that only the public key can be used to encrypt messages and only the corresponding private key can be used to decrypt them. Moreover, it is virtually impossible to deduce the private key if you know the public key.

When David wants to send a secure message to Donna, he uses Donna’s public key to encrypt the message. Donna then uses her private key to decrypt it.

Public key cryptography was invented in 1976 by Whitfield Diffie and Martin Hellman. It is also called asymmetric encryption because it uses two keys instead of one key (symmetric encryption).

Digital Signatures Process

Using David and Donna, we can demonstrate how digital signatures are work.

From David’s point of view, the signing process operation is simple. But few steps are happening while signing process is started. :

Generating a Private and Public Key

For digitally sign documents, David needs to obtain a Private and Public Key – a one-time process , it’s done by Secured Signing Service while user registered. The Private Key isn’t shared and is used only by David sign documents. The Public Key is available for all, used for validate the signatory’s digital signature.