SecurityKeyServicesis an array of the DataType EndpointDescriptionand definesone or more Security Key Servers(SKS) that manage the security keys for the SecurityGroupassigned to the PubSubGroup. The EndpointDescription DataTypeis defined in OPC 10000-4.

The parameter is null if the SecurityMode is NONE_1.

Each element in the array is an Endpointfor an SKS that can supply the security keys for theSecurityGroupId. Multiple Endpointsexist because an SKS may support multiple transport profiles and/or may have multiple redundant instances. The UserTokenPoliciesin each Endpointspecify what user credentials are required. OPC 10000-4describes UserTokenPoliciesin more detail.