The correct answer is Public.Digital signaturesIt is based on public-key cryptography, also known as asymmetric cryptography.It is the public-key primitives of message authentication.In the physical world, it is common to use handwritten signatures on handwritten or typed messages.It is used to bind the signatory to the message.Similarly, a digital signature is a technique that binds a person/entity to the digital data. This binding can be independently verified by the receiver as well as any third party.It is a cryptographic value that is calculated from the data and a secret key known only by the signer.In the real world, the receiver of the message needs assurance that the message belongs to the sender and he should not be able to repudiate the origination of that message.This requirement is very crucial in business applications since the likelihood of a dispute over exchanged data is very high.