What is the function of a digital signature?

• A. To encrypt messages for secure transmission
• B. To authenticate the source and ensure message integrity
• C. To create a temporary session key
• D. To compress data for quicker transmission

Answer: (B)

A digital signature plays a crucial role in the realm of cybersecurity and information privacy by providing a means to authenticate the source of a message and ensure its integrity. When a sender signs a document or message with their private key, they create a unique digital signature that is mathematically linked to the content of that message. This allows the recipient to verify that the message originated from the claimed sender and that it has not been altered in transit.

The authentication process is established because only the sender possesses the corresponding private key, enabling the recipient to verify the signature using the sender's public key. If the message were tampered with after being signed, the signature would become invalid, signaling that the integrity of the message has been compromised.

In contrast, encrypting messages for secure transmission would primarily focus on confidentiality rather than the dual function of authentication and integrity that digital signatures provide. A digital signature does not create a temporary session key or compress data for quicker transmission, as those functions pertain to other aspects of data handling and transmission protocols. Thus, the essence of a digital signature resides in its ability to confirm identity and safeguard against unauthorized modifications.