\HeadingLevelB{Ascend and Phantom}
\label{sec:sgx_related_ascend}

The Ascend \citep{fletcher2012ascend} and Phantom \citep{maas2013phantom} secure
processors introduced practical implementations of Oblivious RAM
\citep{goldreich1987oram} techniques in the CPU's memory controller. These
processors are resilient to attackers who can probe the DRAM address bus and
attempt to learn a container's private information from its DRAM memory access
pattern.

Implementing an ORAM scheme in a memory controller is largely orthogonal to the
other secure architectures described above. It follows, for example, that
Ascend's ORAM implementation can be combined with Aegis' memory encryption and
authentication, and with Sanctum's hardware extensions and security monitor,
yielding a secure processor that can withstand both software attacks and
physical DRAM attacks.
