An overview of IPSec
IPSec is a standard suite of protocols that provides security at layer 3, or the IP layer, and was designed to provide the following security features when transferring packets across a network:
Authentication: This verifies that the received packet is from the legitimate sender
Integrity: This ensures that the contents of the packet did not change during transit
Confidentiality: This conceals the payload through the use of encryption
IPSec contains many elements, which will be discussed in the following sections.
Encapsulating Security Payload
Encapsulating Security Payload (ESP) provides authentication, integrity, and confidentiality, which help protect against data tampering and provide message content protection. IPSec implements industry standard algorithms, such as SHA and MD5, to produce a unique identifier for each packet that cannot be forged. These "fingerprints" allow the receiver to determine whether a packet has been tampered with. Packets that are not authenticated...
