IPSec

IPsec is a security protocol for the Internet Protocol layer that you can use, for example, to set up a secure tunnel between machines or networks.

It consists of these subprotocols:

AH (Authentication Header)

Guarantees the integrity of the IP packet and protects it from intermediate alteration or impersonation, by attaching a cryptographic checksum computed by one-way hash functions.

ESP (Encapsulated Security Payload)

Protects the IP payload from wire-tapping, by encrypting it using secret-key cryptography algorithms.

IPsec has these modes of operation:

Transport

Protects peer-to-peer communication between end nodes.

Tunnel

Supports IP-in-IP encapsulation operation and is designed for security gateways, such as VPN configurations.

For more information, see IPSec in the QNX OS C Library Reference (I page).