Two users need to send each other emails over unsecured channels.
The system should support the principle of non-repudiation.
Which of the following should be used to sign the user's certificates?
Click on the arrows to vote for the correct answer
A. B. C. D.B.
To ensure non-repudiation, which means that the sender of a message cannot later deny having sent it, the users need to sign their emails using digital certificates. Digital certificates are issued and signed by a Certificate Authority (CA) to verify the identity of the sender and recipient of the message.
Therefore, the correct answer to the question is option B, CA.
Option A, RA (Registration Authority), is an entity that assists in the verification of the identity of individuals or organizations requesting digital certificates. It acts as an intermediary between the certificate requester and the CA.
Option C, CRL (Certificate Revocation List), is a list of revoked or invalidated digital certificates that a CA maintains. It is used to check whether a particular digital certificate is still valid.
Option D, CSR (Certificate Signing Request), is a request made by an applicant to a CA to issue a digital certificate. The CSR contains the applicant's public key and other identifying information.