Which of the following would effectively verify the originator of a transaction?

A.
Using a secret password between the originator and the receiver

B.
Encrypting the transaction with the receiver’s public key

C.
Using a portable document format (PDF) to encapsulate transaction content

D.
Digitally signing the transaction with the source’s private key

Explanation:
A digital signature is an electronic identification of a person, created by using a public key algorithm, to verify to
a recipient the identity of the source of a transaction and the integrity of its content. Since they are a ‘shared
secret’ between the user and the system itself, passwords are considered a weaker means of authentication.
Encrypting the transaction with the recipient’s public key will provide confidentiality for the information, while
using a portable document format(PDF) will probe the integrity of the content but not necessarily authorship.