Working with digital signatures

A digital signature is a cryptographic technique that uses asymmetric encryption to provide several services for both sender and receiver. Instead of encrypting an entire document, a digital signature encrypts only a hash of the message, therefore using a smaller footprint.

In this section, we'll see how a digital signature can ensure message authentication, integrity, and non-repudiation. Then, we'll step through the process so that you can see how all of these are accomplished when creating a signature.

Let's start with how we can provide three core security services.

Providing core security services

Because of the vast anonymous nature of the internet, many felt that there needed to be a way of creating and signing a document, using a digital format. The method was to address the issue of being able to complete transactions on the internet without requiring a physical or wet signature, whereby someone physically marks...