Within the Encrypted Security Payload extension header, which of the following uniquely identifies
each packet?

A.
Padding

B.
Sequence number

C.
Security parameters index

D.
Payload type

Explanation:
The sequence number is a 32-bit unsigned number used to provide anti-replay abilities. It uniquely
identifies the message within the data stream.
Incorrect Answers:
A: Padding is used to control the size and alignment of the message. The Pad Length indicates
the number of 8-bit passing bytes to be added after the data.
D: The ESP header does not have a field called the payload type. There is payload data and
payload length, for the length of the payload. The type of payload is actually stored in the next
header field.