[tor-relays] [tor-talk] HardwareAccel: Current proper use???

coderman coderman at gmail.com
Sat Jan 3 12:34:25 UTC 2015

On 1/3/15, usprey <usprey at gmail.com> wrote:
> Summary:
> The documentation is still somewhat vague on the best use of the
> "HardwareAccel" option.

you could submit a patch ;)

>> *HardwareAccel* *0*|*1*
>> If non-zero, try to use built-in (static) crypto hardware acceleration
>> when available. (Default: 0)

in OpenSSL land, there are two types of crypto offload / hw engines:
 built-in (static), and dynamically loaded (dynamic).

the "HardwareAccel 1" option says to enable the built-in / static
engines.  you may have a patched OpenSSL that will automatically try
dynamic engines without explicitly attempting to load them by name (as
libengine.so dlopen'ed implementations).

> https://www.torservers.net/wiki/setup/server#aes-ni_crypto_acceleration
> claims
> no intervention is needed in regards of aes-ni accelaration, but I would
> like to add an explanation or source to this recommendation.

in some versions of OpenSSL, you will need to enable HardwareAccel
(but not use a dynamic engine - aesni is built-in / static).

you will need to consult the distribution of OpenSSL you are using to
be sure - it varies by version and pkg maintainers.

> Question_1:
> If my CPU supports and have loaded aesni_intel on linux with OpenSSL is
> 1.0.1.j-1, should I leave HardwareAccel off or explicitly enable it?

leave HardwareAccel 1, but do not bother with a dynamic named engine opt.

More information about the tor-relays mailing list