<s>
TLS	B-Protocol
acceleration	I-Protocol
(	O
formerly	O
known	O
as	O
SSL	B-Protocol
acceleration	I-Protocol
)	O
is	O
a	O
method	O
of	O
offloading	O
processor-intensive	O
public-key	B-Application
encryption	I-Application
for	O
Transport	B-Protocol
Layer	I-Protocol
Security	I-Protocol
(	O
TLS	O
)	O
and	O
its	O
predecessor	O
Secure	B-Protocol
Sockets	I-Protocol
Layer	I-Protocol
(	O
SSL	O
)	O
to	O
a	O
hardware	O
accelerator	O
.	O
</s>
<s>
Typically	O
this	O
means	O
having	O
a	O
separate	O
card	O
that	O
plugs	O
into	O
a	O
PCI	B-Protocol
slot	I-Protocol
in	O
a	O
computer	O
that	O
contains	O
one	O
or	O
more	O
coprocessors	B-General_Concept
able	O
to	O
handle	O
much	O
of	O
the	O
SSL	O
processing	O
.	O
</s>
<s>
TLS	O
accelerators	O
may	O
use	O
off-the-shelf	O
CPUs	B-General_Concept
,	O
but	O
most	O
use	O
custom	O
ASIC	O
and	O
RISC	B-Architecture
chips	O
to	O
do	O
most	O
of	O
the	O
difficult	O
computational	O
work	O
.	O
</s>
<s>
During	O
the	O
TLS	O
handshake	O
the	O
server	O
and	O
the	O
client	O
establish	O
session	O
keys	O
(	O
symmetric	B-Algorithm
keys	I-Algorithm
,	O
used	O
for	O
the	O
duration	O
of	O
a	O
given	O
session	O
)	O
,	O
but	O
the	O
encryption	O
and	O
signature	O
of	O
the	O
TLS	O
handshake	O
messages	O
itself	O
is	O
done	O
using	O
asymmetric	B-Application
keys	I-Application
,	O
which	O
requires	O
more	O
computational	O
power	O
than	O
the	O
symmetric	B-Algorithm
cryptography	I-Algorithm
used	O
for	O
the	O
encryption/decryption	O
of	O
the	O
session	O
data	O
.	O
</s>
<s>
Typically	O
a	O
hardware	O
TLS	O
accelerator	O
will	O
offload	O
processing	O
of	O
the	O
TLS	O
handshake	O
while	O
leaving	O
it	O
to	O
the	O
server	O
software	O
to	O
process	O
the	O
less	O
intense	O
symmetric	B-Algorithm
cryptography	I-Algorithm
of	O
the	O
actual	O
TLS	O
data	B-General_Concept
exchange	I-General_Concept
,	O
but	O
some	O
accelerators	O
handle	O
all	O
TLS	O
operations	O
and	O
terminate	O
the	O
TLS	O
connection	O
,	O
thus	O
leaving	O
the	O
server	O
seeing	O
only	O
decrypted	O
connections	O
.	O
</s>
<s>
Sometimes	O
data	O
centers	O
employ	O
dedicated	O
servers	O
for	O
TLS	B-Protocol
acceleration	I-Protocol
in	O
a	O
reverse	B-General_Concept
proxy	I-General_Concept
configuration	O
.	O
</s>
<s>
Modern	O
x86	B-Operating_System
CPUs	B-General_Concept
support	O
Advanced	B-Algorithm
Encryption	I-Algorithm
Standard	I-Algorithm
(	O
AES	B-Algorithm
)	O
encoding	O
and	O
decoding	O
in	O
hardware	O
,	O
using	O
the	O
AES	B-Algorithm
instruction	I-Algorithm
set	I-Algorithm
proposed	O
by	O
Intel	O
in	O
March	O
2008	O
.	O
</s>
<s>
Allwinner	B-Architecture
Technology	I-Architecture
provides	O
a	O
hardware	O
cryptographic	O
accelerator	O
in	O
its	O
A10	O
,	O
A20	O
,	O
A30	O
and	O
A80	O
ARM	B-Architecture
system-on-chip	B-Architecture
series	O
,	O
and	O
all	O
ARM	B-Architecture
CPUs	B-General_Concept
have	O
acceleration	O
in	O
the	O
later	O
ARMv8	O
architecture	O
.	O
</s>
<s>
The	O
accelerator	O
provides	O
the	O
RSA	B-Architecture
public-key	B-Application
algorithm	O
,	O
several	O
widely	O
used	O
symmetric-key	B-Algorithm
algorithms	I-Algorithm
,	O
cryptographic	B-Algorithm
hash	I-Algorithm
functions	I-Algorithm
,	O
and	O
a	O
cryptographically	O
secure	O
pseudo-random	B-Algorithm
number	I-Algorithm
generator	I-Algorithm
.	O
</s>
