IP security option (IP) (IPSO)

The IP Security Option ( IPSO) is a U.S. government specification of an optional data field in the IP header for hierarchical security levels. IPSO is described in the TCP/IP standards documentRFC 1038.

IPSO uses sensitive labels that are used in special routers and switches to transmit trusted data to the appropriate receiving devices. For this purpose, an optional data field is inserted in the IP header of the IPSO protocol, which consists of four different data fields: protocol type, header length, classification and protection level, and protection authority flag. The header length field has a variable size and is at least 4 bytes, and the classification field specifies one of four classifications: Top Secret, Secret, Confidential or Unclassified, and in the Protection Authorities flags the accredited institutions are entered.