A sender S sends a message m to receiver R, which is digitally signed by S…
2025
A sender S sends a message m to receiver R, which is digitally signed by S with its private key. In this scenario, one or more of the following security violations can take place.
I. S can launch a birthday attack to replace m with a fraudulent message II. A third party attacker can launch a birthday attack to replace m with a fraudulent message III. R can launch a birthday attack to replace m with a fraudulent message
Which of the following are possible security violations?
- A.
I and II only
- B.
I only
- C.
III only
- D.
II and III only
Attempted by 40 students.
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Correct answer: B
In digital signatures, the sender S can launch a birthday attack to find hash collisions. This allows S to replace message m with a fraudulent one while maintaining the same signature. Third parties cannot forge signatures without S's private key, and R cannot alter m after verification.