What is the less secure AES encryption mode?

Which of the following enables secure and private data exchange/transfer on an unsecure public network ?

Which of the following is a VALID ephemeral key?

Which of the following keys are used to encrypt other keys using symmetric key algorithms ?

Which of the following are the public keys of asymmetric (public) key pairs that are used to encrypt keys using a public key algorithm?

What does the Linux kernal use to sandbox running programs?

Allen wants to sign a message which he is sending to Mark. Which key will Allen use to sign the message?

The ability to exploit a vulnerability is called:

Which goal cannot be achieved with Symmetric cryptography?

Which protocol use UDP:

Select the objectives of E-mail security.