usm DH User Authentication Key Change

1.3.6.1.3.101.1.1.2.1.1

The object used to change any given user's Authentication Key using a Diffie-Hellman key exchange. The right-most n bits of the shared secret 'sk', where 'n' is the number of bits required for the protocol defined by usmUserAuthProtocol, are installed as the operational authentication key for this row after a successful SET.