PrepAway - Latest Free Exam Questions & Answers

This objective can be achieved by:

An investment advisor e-mails periodic newsletters to clients and wants reasonable assurance that no one has
modified the newsletter. This objective can be achieved by:

PrepAway - Latest Free Exam Questions & Answers

A.
encrypting the hash of the newsletter using the advisor’s private key.

B.
encrypting the hash of the newsletter using the advisor’s public key.

C.
digitally signing the document using the advisor’s private key.

D.
encrypting the newsletter using the advisor’s private key.

Explanation:
There is no attempt on the part of the investment advisor to prove their identity or to keep the newsletter
confidential. The objective is to assure the receivers that it came to them without any modification, i.e., it has
message integrity. Choice Ais correct because the hash is encrypted using the advisor’s private key. The
recipients can open the newsletter, recompute the hash and decrypt the received hash using the advisor’s
public key. If the two hashes are equal, the newsletter was not modified in transit. Choice B is not feasible, for
no one other than the investment advisor can open it. Choice C addresses sender authentication but not
message integrity. Choice D addresses confidentiality, but not message integrity, because anyone can obtain
the investment advisor’s public key, decrypt the newsletter, modify it and send it to others. The interceptor will
not be able to use the advisor’s private key, because they do not have it. Anything encrypted using the
interceptor’s private key can be decrypted by the receiver only by using their public key.


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