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Service A hashes a message, resulting in message digest X. Service A encrypts message digest X with its private key, resulting in cipher text X1. Service A sends the message and X1 to Service B. Service B hashes the message, resulting in message digest Y. Service B decrypts X1 with Service A's public key, recovering message digest X1. Service B compares X and Y and finds them not to be equal. This proves that;
Suggested Answer: D
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30 comments · newest first
LE
Lemuel
10 months ago
All of the above sounds right to me!
GE
Geoffrey
10 months ago
Public key cryptography was definitely used here.
BR
Brett
10 months ago
The message was definitely altered.
DU
Dulce
11 months ago
Wait, how can we be sure the message was altered?
EL
Elenore
11 months ago
I agree, that's the only conclusion.
SH
Shaquana
11 months ago
I think all of the options could be true in this context, especially since the message digest comparison is a key part of verifying integrity.
MA
Margurite
11 months ago
I feel like the fact that Service B decrypted with the public key is important, but I can't recall if that alone proves anything about the message being altered.
AR
Arthur
11 months ago
This scenario seems similar to a practice question we did about digital signatures. I think if the digests don’t match, it indicates tampering.
ED
Edward
12 months ago
I remember studying how hashing and encryption work together, but I'm not entirely sure if the comparison of digests directly proves the message was altered.
AV
Avery
12 months ago
Alright, let me break this down. The fact that the message digests don't match means the message was altered. I've got this!
LA
Lavonna
1 year ago
This looks like a classic cryptography question. I'm feeling pretty confident I can work through this step-by-step.
ER
Ernest
1 year ago
I'm a bit confused about the role of the public and private keys here. I'll need to review that part of the material again.
EL
Elmira
1 year ago
Okay, I think I've got this. The key is to focus on the comparison of the message digests and what that implies.
LA
Laila
1 year ago
Hmm, this seems like a tricky one. I'll need to carefully think through the steps to make sure I understand what's happening.
NG
Ngoc
1 year ago
I wonder if Service A and Service B are on speaking terms after this little mix-up. Maybe they need to have a 'hash it out' session.
RE
Reita
1 year ago
I think the answer is D) All of the above, as it covers all possibilities.
AN
Annett
1 year ago
I agree with Joaquin, C) public key cryptography makes more sense.
RO
Robt
1 year ago
This is a tricky one, but I'll go with D. All of the above. The differences in the message digests indicate the message was altered, and the use of public key cryptography is evident.
WA
Wai
1 year ago
I think D is the right answer too. The mismatch in the message digests shows the message was tampered with.
MA
Margot
1 year ago
I agree, D seems like the correct choice. The message was altered and public key cryptography was used.
JA
Janessa
1 year ago
I'm going with B. Only Service A sent this particular message. The decryption of the cipher text with Service A's public key confirms the sender's identity.
GA
Galen
1 year ago
Definitely D. The fact that the message digests don't match proves the message was altered, and the use of public key cryptography is a clear giveaway.
HI
Hillary
1 year ago
User 2: Agreed. It's a clever way to ensure the integrity and authenticity of the message.
PA
Paris
1 year ago
User 1: Definitely D. The fact that the message digests don't match proves the message was altered, and the use of public key cryptography is a clear giveaway.
JO
Joaquin
1 year ago
I disagree, I believe the answer is C) public key cryptography was used.
WI
Willis
1 year ago
I think the answer is A) the message was altered.
GI
Gianna
1 year ago
Hmm, I think the answer is D. All of the above. The message was altered, and public key cryptography was used to verify the sender's identity.
MA
Matt
1 year ago
Definitely D. It's the most comprehensive option that covers all the scenarios.
CO
Cordie
1 year ago
Yes, D makes sense. It shows that the message was altered and public key cryptography was used.
LA
Lavelle
1 year ago
I agree, D seems like the correct answer. It covers all the possibilities.