정답: A
Digital non-repudiation requires a trusted third-party. Non-repudiation is a security property that prevents a party from denying or disputing the validity or authenticity of a digital document, such as a message, transaction, or contract. Non-repudiation can help to ensure the accountability, reliability, and integrity of the digital document, as well as to provide the evidence and proof of the digital document. Non-repudiation can be achieved by using various methods or techniques, such as digital signatures, timestamps, or certificates. Digital non-repudiation is a type of non- repudiation that uses a cryptographic technique to verify the authenticity, integrity, and non- repudiation of a digital document. Digital non-repudiation requires a trusted third-party, which is a person or entity that is independent, impartial, and reliable, and that provides a service or function that facilitates or supports the digital non-repudiation process. A trusted third-party can help to provide digital non-repudiation, by issuing, managing, or verifying the cryptographic keys, certificates, or signatures that are used to create or validate the digital document, as well as by maintaining or providing the records, logs, or timestamps that are used to prove or confirm the digital document. A trusted third- party can also help to resolve any disputes or conflicts that may arise from the digital document, by acting as an arbitrator, mediator, or witness. Appropriate corporate policies, symmetric encryption, or multifunction access cards are not the requirements for digital non-repudiation, as they are either irrelevant, insufficient, or ineffective for digital non- repudiation.
