sign_official_build: switch from dgst to pkeyutl

For sign_update_payload, using openssl dgst results in double hashing.
Switch over to pkeyutl to only hash once.

BUG=b:299105459
TEST=unit-test
BRANCH=None

Signed-off-by: Benjamin Shai <bshai@google.com>
Change-Id: Iff09422469c697e1d4b08bf869367404b2109a0a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/5120408
Reviewed-by: Ching-Kang Yen <chingkang@chromium.org>
Reviewed-by: Jack Neus <jackneus@google.com>
Reviewed-by: George Engelbrecht <engeg@google.com>
Reviewed-by: John L Chen <zuan@chromium.org>
1 file changed