<s>
Hardware-based	B-Device
encryption	I-Device
is	O
the	O
use	O
of	O
computer	B-Architecture
hardware	I-Architecture
to	O
assist	O
software	O
,	O
or	O
sometimes	O
replace	O
software	O
,	O
in	O
the	O
process	O
of	O
data	O
encryption	O
.	O
</s>
<s>
Typically	O
,	O
this	O
is	O
implemented	O
as	O
part	O
of	O
the	O
processor	B-Device
's	O
instruction	O
set	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
AES	B-Algorithm
encryption	I-Algorithm
algorithm	O
(	O
a	O
modern	O
cipher	B-Application
)	O
can	O
be	O
implemented	O
using	O
the	O
AES	B-Algorithm
instruction	I-Algorithm
set	I-Algorithm
on	O
the	O
ubiquitous	O
x86	B-Operating_System
architecture	I-Operating_System
.	O
</s>
<s>
Such	O
instructions	O
also	O
exist	O
on	O
the	O
ARM	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
However	O
,	O
more	O
unusual	O
systems	O
exist	O
where	O
the	O
cryptography	O
module	O
is	O
separate	O
from	O
the	O
central	O
processor	B-Device
,	O
instead	O
being	O
implemented	O
as	O
a	O
coprocessor	B-General_Concept
,	O
in	O
particular	O
a	O
secure	O
cryptoprocessor	O
or	O
cryptographic	B-General_Concept
accelerator	I-General_Concept
,	O
of	O
which	O
an	O
example	O
is	O
the	O
IBM	B-Device
4758	I-Device
,	O
or	O
its	O
successor	O
,	O
the	O
IBM	B-Device
4764	I-Device
.	O
</s>
<s>
Hardware	B-Architecture
implementations	O
can	O
be	O
faster	O
and	O
less	O
prone	O
to	O
exploitation	O
than	O
traditional	O
software	O
implementations	O
,	O
and	O
furthermore	O
can	O
be	O
protected	O
against	O
tampering	O
.	O
</s>
<s>
Prior	O
to	O
the	O
use	O
of	O
computer	B-Architecture
hardware	I-Architecture
,	O
cryptography	O
could	O
be	O
performed	O
through	O
various	O
mechanical	O
or	O
electro-mechanical	O
means	O
.	O
</s>
<s>
An	O
early	O
example	O
is	O
the	O
Scytale	O
used	O
by	O
the	O
Spartans	B-Application
.	O
</s>
<s>
The	O
Enigma	O
machine	O
was	O
an	O
electro-mechanical	O
system	O
cipher	B-Application
machine	O
notably	O
used	O
by	O
the	O
Germans	O
in	O
World	O
War	O
II	O
.	O
</s>
<s>
However	O
,	O
the	O
application	O
of	O
computers	O
to	O
cryptography	O
in	O
general	O
dates	O
back	O
to	O
the	O
1940s	O
and	O
Bletchley	O
Park	O
,	O
where	O
the	O
Colossus	B-Device
computer	I-Device
was	O
used	O
to	O
break	O
the	O
encryption	O
used	O
by	O
German	O
High	O
Command	O
during	O
World	O
War	O
II	O
.	O
</s>
<s>
It	O
was	O
only	O
with	O
the	O
development	O
of	O
the	O
microcomputer	B-Architecture
that	O
computer	O
encryption	O
became	O
feasible	O
,	O
outside	O
of	O
niche	O
applications	O
.	O
</s>
<s>
The	O
X86	B-Operating_System
architecture	I-Operating_System
,	O
as	O
a	O
CISC	O
(	O
Complex	B-Architecture
Instruction	I-Architecture
Set	I-Architecture
Computer	I-Architecture
)	O
Architecture	B-General_Concept
,	O
typically	O
implements	O
complex	O
algorithms	O
in	O
hardware	B-Architecture
.	O
</s>
<s>
The	O
x86	B-Operating_System
architecture	I-Operating_System
implements	O
significant	O
components	O
of	O
the	O
AES	B-Algorithm
(	O
Advanced	O
Encryption	O
Standard	O
)	O
algorithm	O
,	O
which	O
can	O
be	O
used	O
by	O
the	O
NSA	O
for	O
Top	B-Application
Secret	I-Application
information	O
.	O
</s>
<s>
The	O
architecture	B-General_Concept
also	O
includes	O
support	O
for	O
the	O
SHA	O
Hashing	B-Error_Name
Algorithms	I-Error_Name
through	O
the	O
Intel	B-Device
SHA	I-Device
extensions	I-Device
.	O
</s>
<s>
Whereas	O
AES	B-Algorithm
is	O
a	O
cipher	B-Application
,	O
which	O
is	O
useful	O
for	O
encrypting	O
documents	O
,	O
hashing	B-Error_Name
is	O
used	O
for	O
verification	O
,	O
such	O
as	O
of	O
passwords	O
(	O
see	O
PBKDF2	O
)	O
.	O
</s>
<s>
ARM	B-Architecture
processors	I-Architecture
can	O
optionally	O
support	O
Security	O
Extensions	O
.	O
</s>
<s>
Although	O
ARM	O
is	O
a	O
RISC	B-Architecture
(	O
Reduced	B-Architecture
Instruction	I-Architecture
Set	I-Architecture
Computer	I-Architecture
)	O
architecture	B-General_Concept
,	O
there	O
are	O
several	O
optional	O
extensions	O
specified	O
by	O
ARM	O
Holdings	O
.	O
</s>
<s>
IBM	B-Device
4758	I-Device
–	O
The	O
predecessor	O
to	O
the	O
IBM	B-Device
4764	I-Device
.	O
</s>
<s>
This	O
includes	O
its	O
own	O
specialised	O
processor	B-Device
,	O
memory	B-Architecture
and	O
a	O
Random	O
Number	O
Generator	O
.	O
</s>
<s>
IBM	B-Device
4764	I-Device
and	O
IBM	B-Device
4765	I-Device
,	O
identical	O
except	O
for	O
the	O
connection	O
used	O
.	O
</s>
<s>
Both	O
are	O
peripheral	B-Device
devices	I-Device
that	O
plug	O
into	O
the	O
motherboard	B-Device
.	O
</s>
<s>
Advanced	O
Micro	O
Devices	O
(	O
AMD	O
)	O
processors	O
are	O
also	O
x86	B-Operating_System
devices	O
,	O
and	O
have	O
supported	O
the	O
AES	B-Algorithm
instructions	I-Algorithm
since	O
the	O
2011	O
Bulldozer	O
processor	B-Device
iteration	O
.	O
</s>
<s>
They	O
also	O
exist	O
on	O
many	O
tablets	O
and	O
smartphones	O
due	O
to	O
their	O
implementation	O
in	O
ARM	B-Architecture
processors	I-Architecture
.	O
</s>
<s>
Implementing	O
cryptography	O
in	O
hardware	B-Architecture
means	O
that	O
part	O
of	O
the	O
processor	B-Device
is	O
dedicated	O
to	O
the	O
task	O
.	O
</s>
<s>
In	O
particular	O
,	O
modern	O
processor	B-Device
architectures	O
that	O
support	O
pipelining	B-General_Concept
can	O
often	O
perform	O
other	O
instructions	O
concurrently	O
with	O
the	O
execution	O
of	O
the	O
encryption	O
instruction	O
.	O
</s>
<s>
Furthermore	O
,	O
hardware	B-Architecture
can	O
have	O
methods	O
of	O
protecting	O
data	O
from	O
software	O
.	O
</s>
<s>
Consequently	O
,	O
even	O
if	O
the	O
operating	B-General_Concept
system	I-General_Concept
is	O
compromised	O
,	O
the	O
data	O
may	O
still	O
be	O
secure	O
(	O
see	O
Software	O
Guard	O
Extensions	O
)	O
.	O
</s>
<s>
If	O
,	O
however	O
,	O
the	O
hardware	B-Architecture
implementation	O
is	O
compromised	O
,	O
major	O
issues	O
arise	O
.	O
</s>
<s>
Malicious	O
software	O
can	O
retrieve	O
the	O
data	O
from	O
the	O
(	O
supposedly	O
)	O
secure	O
hardware	B-Architecture
–	O
a	O
large	O
class	O
of	O
method	O
used	O
is	O
the	O
timing	O
attack	O
.	O
</s>
<s>
This	O
is	O
far	O
more	O
problematic	O
to	O
solve	O
than	O
a	O
software	O
bug	O
,	O
even	O
within	O
the	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Similarly	O
,	O
regular	O
security	O
updates	O
are	O
released	O
for	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
and	O
Linux	B-Application
,	O
as	O
well	O
as	O
mobile	O
operating	B-General_Concept
systems	I-General_Concept
like	O
iOS	B-Application
,	O
Android	B-Application
,	O
and	O
Windows	B-Protocol
Phone	I-Protocol
.	O
</s>
<s>
However	O
,	O
hardware	B-Architecture
is	O
a	O
different	O
issue	O
.	O
</s>
<s>
Sometimes	O
,	O
the	O
issue	O
will	O
be	O
fixable	O
through	O
updates	O
to	O
the	O
processor	B-Device
's	O
microcode	B-Device
(	O
a	O
low	O
level	O
type	O
of	O
software	O
)	O
.	O
</s>
<s>
However	O
,	O
other	O
issues	O
may	O
only	O
be	O
resolvable	O
through	O
replacing	O
the	O
hardware	B-Architecture
,	O
or	O
a	O
workaround	O
in	O
the	O
operating	B-General_Concept
system	I-General_Concept
which	O
mitigates	O
the	O
performance	O
benefit	O
of	O
the	O
hardware	B-Architecture
implementation	O
,	O
such	O
as	O
in	O
the	O
Spectre	B-Error_Name
exploit	I-Error_Name
.	O
</s>
