What Is a Digital Signature?

Click here for Digital Signature How does a Digital Signature Work?

The digital signature can be considered as a numerical value that is represented as a sequence of characters. The creation of a digital signature is a complex mathematical process that can only be created by a computer.

Consider a scenario where Alice has to digitally sign a file or an email and send it to Bob.

• Alice selects the file to be digitally signed or clicks on 'sign' in her email application
• The hash value of the file content or the message is calculated by Alice's computer
• This hash value is encrypted with Alice's Signing Key (which is a Private Key) to create the Digital Signature.
• Now, the original file or email message along with its Digital Signature are sent to Bob.

• After Bob receives the signed message, the associated application (such as email application) identifies that the message has been signed. Bob's computer then proceeds to:

  • Decrypt the Digital Signature using Alice's Public Key
  • Calculate the hash of the original message
  • Compare the (a) hash it has computed from the received message with the (b) decrypted hash received with Alice's message.