nagendra modadugu 927e01da02 g: rework DCRYPTO_app_cipher (AES-CTR) for speed ...

The previous implementation of DCRYPTO_app_cipher
consumed roughly 16ms to cipher a 16kB buffer
(i.e. performance that is far worse than the
hardware is capable of).

This change speeds up the implementation by about
85%, to the tune of roughly 2.2ms for a 16kB buffer.

The gains originate from various sources: loop
unrolling, data-pipelining, eliminating local
variables (to reduce register pressure), eliminating
support for unaligned input/output data, compiling
hot code with -O (rather the default -Os), and
using the hidden key-ladder, which need only be
setup once per reset.

This change also switches from AES-128 to AES-256.

BRANCH=none
BUG=chrome-os-partner:62260
TEST=make buildall succeeds;
	cipher command succeeds;
        TCG tests pass

Change-Id: I133741be6d9f1353d6ae732d0e863b4b18cc8c9e
Signed-off-by: nagendra modadugu <ngm@google.com>
Reviewed-on: https://chromium-review.googlesource.com/433359
Commit-Ready: Nagendra Modadugu <ngm@google.com>
Tested-by: Nagendra Modadugu <ngm@google.com>
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>

2017-01-28 21:37:58 -08:00

835 B

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