Authentication of SKIP Packets

Authentication is used to guarantee the integrity of SKIP packets. In this process, AH authentication protects the integrity of the packets and the mutual authentication of the sender and the receiver.

AH stands for Authentication Header. This header has been defined for the authentication of IP packets by the IPSEC working group of the ETIF. Packet authentication is performed with a keyed hash function to create a MAC that guarantees the integrity of the packet. When the sender transmits a packet, it calculates a hash of the IP packet along with a key and includes it in the packet. When the packet is received, the receiver calculates the hash over the IP packet and the key as well. If the value that the receiver calculates is the same as the one that the sender included in the packet, the packet has been authenticated. If someone modified the packet in transmission, the value that the receiver calculates will not match the one that the sender calculated and the packet fails authentication and is discarded.