Chapter 14: Virtual Private Networks—VPN LANCOM Reference Manual LCOS 3.50
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Virtual Private Networks—
VPN
The AH process in the sender
In the sender, the authentication data is generated in 3 steps.
햲A checksum is calculated for the complete package using a hash
algorithm.
햳This checksum is once again sent through a hash algorithm together with
a key known to both the sender and the recipient.
햴This results in the required authentication data which is inserted in the AH
header.
Checking of integrity and authenticity by the recipient
The AH protocol works in a very similar manner at the recipient's end. The
recipient also uses his key to calculate the authentication data for the received
Authentication data,
ICV
Checksum
(hash code)
햲
햳
햴
IP header AH header Data
햴