IPSEC

Question 1

What are the available protocls in IPSec? explain what they offer.

Answer 1

1. Authentication header - data origin authentication and replay protection.
2. Encapsulated security payload - data origin authentication, confidentiality and replay protection.

Question 2

How does IPSec protect against replay attacks?

Answer 2

Sequence number.
Sequence number is set to zero in the beginning and increased by one with every packet.
receiver checks if the sequence number is within its window and accepts or rejects it.

Question 3

What are the protocol modes existing?

Answer 3

Transport mode - Used when the cryptographic endpoints are also the communication endpoints of the secured packets
tunnel mode - used when at least one cryptographic endpoint is not a communication endpoint