Question

Explain how timestamping would be used in a protocol to mitigate replay attack.

Answer 1

Replay attack :

For example: when one makes an order to the bank to transfer money to some specified account, the attacker may eavesdrop the frames. If that happens, the attacker can send the same (correct) messages to the bank one more time, hoping that the bank will transfer money again to the same account (probably connected with the intruder).

Using Timestamp to mitigate replay attack.

• Measure for this type of attack is using timestamps on all messages. This prevents hackers from resending messages sent longer ago than a certain length of time, thus reducing the window of opportunity for an attacker to eavesdrop, siphon off the message, and resend it. But alone timestamp can’t prevent replay attack.
• But we can use hash a time-stamp along with the user name and password, and close the window for replay attacks to within a couple of seconds. But still its partial solution only.