Long description

Part (a): There is a vertical block with two partitions. The first partition has three squared blocks from left to right. The first squared block is labeled Client, the second is labeled Server, and the third is labeled Collaborator. The second partition is labeled as Kernel. Part (b): There is a vertical block with two partitions. The first partition has three squared blocks from left to right. The second squared block is encircled and labeled as Encapsulated server and a circular dashed line labeled Covert channel from the second squared block points to the third squared block. The second partition is labeled Kernel.