The correct answer is Digital Signature.Digital Signature: ?A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents.A digital signature provides message integrity, message authentication but not confidentiality.Important PointsMessage authentication: It ensures that message has been sent by a genuine identity and not by an imposter.In this, the receiver needs to be sure of the senders identity.It is a service beyond message integrity. Message integrity:It means that data must arrive at the receiver exactly as they were sent.There must be no changes during the transmission, neither accidentally nor maliciously.Message confidentiality:It means that the sender and the receiver expect confidentiality.The transmitted message must make sense to only the intended receiver.To all others, the message must be garbage.?