(PHP 5 >= 5.4.0)
SNMP::setSecurity — Configures security-related SNMPv3 session parameters
$sec_level
   [, string $auth_protocol = 
   [, string $auth_passphrase = 
   [, string $priv_protocol = 
   [, string $priv_passphrase = 
   [, string $contextName = 
   [, string $contextEngineID = 
  ]]]]]] )setSecurity configures security-related session parameters used in SNMP protocol version 3
sec_level
    the security level (noAuthNoPriv|authNoPriv|authPriv)
auth_protocol
    the authentication protocol (MD5 or SHA)
auth_passphrase
    the authentication pass phrase
priv_protocol
    the privacy protocol (DES or AES)
priv_passphrase
    the privacy pass phrase
contextName
    the context name
contextEngineID
    the context EngineID
   Returns TRUE on success or FALSE on failure.
  
Example #1 SNMP::setSecurity() example
<?php
  $session = new SNMP(SNMP::VERSION_3, $hostname, $rwuser, $timeout, $retries);
  $session->setSecurity('authPriv', 'MD5', $auth_pass, 'AES', $priv_pass, '', 'aeeeff');
?>