authpriv

authPriv is a security level defined in SNMPv3 (Simple Network Management Protocol version 3) within the User-Based Security Model (USM). It provides both authentication and privacy for SNMP messages, meaning that the sender is verified and the message payload is encrypted to protect confidentiality.

Implementation involves configuring SNMPv3 users with an authentication protocol (for example HMAC-SHA-1 or HMAC-SHA-2) and a privacy protocol (for example DES or AES). When a message is transmitted, it is first authenticated to verify the sender, and then encrypted so that the content cannot be read by onlookers. The receiving engine authenticates and decrypts the message before processing it. This level ensures both integrity and confidentiality of SNMP traffic.

Common algorithm choices today favor AES for privacy and SHA-2 for authentication, with DES considered deprecated due to weaknesses. Keys are derived from user credentials and managed by the SNMP engine; effective use depends on secure key provisioning, storage, and periodic rotation.

authPriv is appropriate for environments where monitoring data, device credentials, or configuration details must be protected from eavesdropping and tampering. It introduces additional computational and bandwidth overhead compared to lower security levels and requires compatible hardware and software on both sides. Interoperability may require matching algorithm and key configurations across devices.

In relation to other SNMPv3 security levels, authPriv combines authentication with privacy, offering more protection than authNoPriv or noAuthNoPriv but at greater complexity and cost. It is not applicable to SNMPv1/v2c, which lack the USM-based security model.