Which of the following is the PRIMARY reason for using a digital signature?

A digital signature uses the sender's private key to encrypt a hash of the message, which can then be decrypted by anyone with the sender's public key, proving that the sender indeed originated the message. This process establishes both sender authenticity and message integrity, as any alteration to the message would result in a different hash.

Digital signatures do not provide confidentiality; that is typically achieved through encryption using symmetric or asymmetric keys for the entire message content.

While digital signatures verify data integrity, they authenticate the sender, not the recipient; recipient identity verification is a separate process.

Digital signatures have no direct role in providing availability to a transmission; availability relates to the system's ability to remain accessible and operational.