ETIC SIG, User Manual, Page: 78 / 83

APPENDIX2
VPN basic mechanisms
Page 78
User’s guide ref 9017409-01 SIG Router & VPN server
2 Functions
A VPN provides the functions described hereafter :
Authentication
The VPN ensures that the party with which the communication is set is
actually
the one it claims to be.
Data integrity
The VPN mechanism ensures that information being transmitted over the
public Internet is not altered in any way during transit
Confidentiality
A VPN protects the privacy of information being exchanged between
communicating parties.
3 Operation
Authentication phase
The first operation the end-points carry out is authentication.
2 levels of authentication can be performed using a VPN :
Device level authentication
A code is stored in each end-point (i.e. router or PC); it can be a Key
or a certificate delivered by a certification authority.
During the initial phase, the two end-point exchange their codes; each
party checks that the other party code is valid.
User level authentication
The SIG router holds a user list; once a VPN has been set with the
remote user PC, the remote user identification code and password is
checked.
Encrypted tunnel transmission phase
Once the end-points have exchanged and checked each other identity
code, they set the VPN tunnel.
It is an IP packets exchange; the source and destination IP addresses
are the end-points.
That tunnel encapsulates the encrypted IP data flow transmitted between
any of the devices connected to each end-point.