Presented herein are methodologies for implementing multi-domain cloud security and ways to partition end-points in data center/cloud network topologies into hierarchical domains to increase security and key negotiation efficiency. The methodology includes receiving, from a first endpoint, at a cloud security protocol stack, a packet encrypted in accordance with a cloud security key negotiated between the first endpoint and a second endpoint; extracting a cloud security globally unique domain-id from the packet; querying a cloud security domain repository using the cloud security globally unique domain-id as an index to identify a first cloud security domain, among a plurality of cloud security domains, to which the first endpoint and the second endpoint belong; and selecting the first cloud security domain to process the packet.