Question

alice sends bob an email. she signs the email with a digital signature, created by using her private key. bob can validate the digital signature by using alice's public key. if the signature is valid, it proves that alice sent the email to bob. provided only alice knows her private key, bob is certain the message came from alice. which security service does this demonstrate?

Answer 1

The process described in the scenario is authentication, a security service that verifies a user's identity. It is achieved using a digital signature validated by a public key in the email communication between Alice and Bob.

Step-by-step explanation:

When Alice sends Bob an email with a digital signature using her private key, and Bob verifies the signature with Alice's public key, it demonstrates the security service of authentication. Authentication is a process that confirms a user's identity; in this case, it ensures Bob that the message indeed came from Alice, provided that only Alice has access to her private key. This security service is part of the wider field of cryptography, which provides various methods to secure communication.