4. Symmetric Privacy Protocol

This section describes the Symmetric Privacy Protocol. It provides for protection from disclosure of a received message. An appropriate portion of the message is encrypted according to a secret key known only to the originator and recipient of the message.

This protocol assumes the underlying mechanism is a symmetric encryption algorithm. In addition, the message to be encrypted must be protected according to the conventions of the Digest Authentication Protocol.

Recall from [1] that a SNMPv2 private management communication is represented by an ASN.1 value with the following syntax:

        SnmpPrivMsg ::= [1] IMPLICIT SEQUENCE {
          privDst
             OBJECT IDENTIFIER,
          privData
             [1] IMPLICIT OCTET STRING
        }

For each SnmpPrivMsg value that represents a SNMPv2 private management communication, the following statements are true:

• Its privDst component is called the privacy destination and identifies the SNMPv2 party to which the communication is directed.

• Its privData component is called the privacy data and represents the (possibly encrypted) serialization (according to the conventions of [13] and [12]) of a SNMPv2 authenticated management communication.

• 4.1. Generating a Message
• 4.2. Receiving a Message