Question

Digital signature provides what all security mechanisms

Answer 1

A digital signature is a mathematical scheme for demonstrating the authenticity of digital messages or documents. A valid digital signature gives a recipient reason to believe that the message was created by a known sender (authentication), that the sender cannot deny having sent the message (non-repudiation), and that the message was not altered in transit (integrity).

Answer 2

The security mechanism is as follows :
A digital code is generated and authenticated by public key encryption which is attached to an electronically transmitted document to verify its contents and the sender's identity.