Internet Protocol Security (IPSec)

Group name: grouppage

What to expect

• What is the difference between SSL and IPSec• And when to use it?• Go through the basics for IPSec• Explain IPSec’s key exchange • Look further into ESP, main protocol of IPSec

Internet Protocol (TCP/IP)

Has no inherent security

Man in the middle can read/write to:The TCP/IP headersThe payload data

SSL/TLS and IPSec can encrypt data

IPSec Compared To SSLIPSec

Application Independent

Authenticates IP headers

Encrypts TCP and Application layer

SSL Must be compiled in

Application Insecure IP headers Encrypts application

layer

Malory can: Create packets that have

A's IP as src address Read A's packets Can change A's packets

•Normal IP

IPSec Malroy can do nothing

When to use?

Reasons not to use NAT Support User authentication

Reasons to use: VPN Application doesn't support

TLS Don't want to use PKI Host authentication

IPSec basics for this presentation

Main protocol in IPSec:

–Encapsulating Security Payload (ESP)

Constructs that guide the operation of IPSec

Security Policy (SP)Security Association (SA)

IPSec basics for this presentation

Security Policies

Governs how IPSec process different

datagrams received by an IPSec device

SA describes a particular kind of secure connection between one device and

another.

AH

Security Associations

Security Associations are key to IPSEC’s

authentication and confidentiality mechanisms.

Security Associations

SAs are needed to negotiate in the exchange

of the “shared secret” process

Security Associations

Sharing the shared secret

Sharing the shared secret

IPSec, like many secure networking protocol sets, is based on the concept

of a “shared secret”.

Sharing the shared secret

Before ESP (IPSec protocols) can be used, any two devices must exchange the “secret”

that the ESP themselves will use.

Sharing the shared secret

So how does this happen?

Exchanging the secret

Internet Key Exchange (IKE).

Internet Key Exchange (IKE)

IPSec-capable devices to exchange security associations (SAs), Populate their security association databases (SADs).

Internet Key Exchange (IKE)

These established SAs are then being used for the actual

exchange of secured datagrams with the ESP protocols.

Sharing the shared secret

Source: http://technet.microsoft.com

IPSec Protocols

Encapsulating Security Payload

Encapsulating Security Payload (ESP)

Main function: Provide privacy for IP datagrams

by encrypting them.

ESP packet in transport mode

ESP packet in tunnel mode

New IP Header

Thank You!

The end and we hope you understand

References

• Understanding IPSEC - Server 2003 http://www.youtube.com/watch?v=DH1zI8QYi4A

• TCPIP Guide– http://www.tcpipguide.com/free/

t_IPSecurityIPSecProtocols.htm