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3. Encapsulating Security Protocol Processing

3. Encapsulating Security Protocol Processing​

This section describes the processing of ESP packets in both outbound and inbound directions.

3.1. ESP Header Location​

ESP may be employed in two ways: transport mode or tunnel mode.

3.1.1. Transport Mode Processing​

Details of transport mode processing.

3.1.2. Tunnel Mode Processing​

Details of tunnel mode processing.

3.2. Algorithms​

The mandatory-to-implement algorithms for use with ESP.

3.2.1. Encryption Algorithms​

Encryption algorithm specifications.

3.2.2. Integrity Algorithms​

Integrity algorithm specifications.

3.2.3. Combined Mode Algorithms​

Combined mode algorithm specifications.

3.3. Outbound Packet Processing​

Processing of outbound ESP packets.

3.3.1. Security Association Lookup​

SA lookup for outbound packets.

3.3.2. Packet Encryption and ICV Calculation​

Encryption and ICV calculation procedures.

3.3.3. Sequence Number Generation​

Sequence number generation rules.

3.3.4. Fragmentation​

Fragmentation handling.

3.4. Inbound Packet Processing​

Processing of inbound ESP packets.

3.4.1. Reassembly​

Packet reassembly procedures.

3.4.2. Security Association Lookup​

SA lookup for inbound packets.

3.4.3. Sequence Number Verification​

Sequence number verification procedures.

3.4.4. Integrity Check Value Verification​

ICV verification procedures.