<s>
In	O
computing	O
,	O
a	O
trusted	B-Protocol
client	I-Protocol
is	O
a	O
device	O
or	O
program	O
controlled	O
by	O
the	O
user	O
of	O
a	O
service	O
,	O
but	O
with	O
restrictions	O
designed	O
to	O
prevent	O
its	O
use	O
in	O
ways	O
not	O
authorized	O
by	O
the	O
provider	O
of	O
the	O
service	O
.	O
</s>
<s>
Examples	O
include	O
video	O
games	O
played	O
over	O
a	O
computer	B-Architecture
network	I-Architecture
or	O
the	O
Content	B-Algorithm
Scramble	I-Algorithm
System	I-Algorithm
(	O
CSS	O
)	O
in	O
DVDs	O
.	O
</s>
<s>
Trusted	B-Protocol
client	I-Protocol
software	O
is	O
considered	O
fundamentally	O
insecure	O
:	O
once	O
the	O
security	O
is	O
broken	O
by	O
one	O
user	O
,	O
the	O
break	O
is	O
trivially	O
copyable	O
and	O
available	O
to	O
others	O
.	O
</s>
<s>
Trusted	B-Protocol
client	I-Protocol
hardware	B-Architecture
is	O
somewhat	O
more	O
secure	O
,	O
but	O
not	O
a	O
complete	O
solution	O
.	O
</s>
<s>
Trusted	B-Protocol
clients	I-Protocol
are	O
attractive	O
to	O
business	O
as	O
a	O
form	O
of	O
vendor	O
lock-in	O
:	O
sell	O
the	O
trusted	B-Protocol
client	I-Protocol
at	O
a	O
loss	O
and	O
charge	O
more	O
than	O
would	O
be	O
otherwise	O
economically	O
viable	O
for	O
the	O
associated	O
service	O
.	O
</s>
<s>
Modern	O
examples	O
include	O
video	O
recorders	O
being	O
forced	O
by	O
law	O
to	O
include	O
Macrovision	O
copy	O
protection	O
,	O
the	O
DVD	O
region	O
code	O
system	O
and	O
region-coded	O
video	B-Device
game	I-Device
consoles	I-Device
.	O
</s>
<s>
Trusted	O
computing	O
aims	O
to	O
create	O
computer	B-Architecture
hardware	I-Architecture
which	O
assists	O
in	O
the	O
implementation	O
of	O
such	O
restrictions	O
in	O
software	O
,	O
and	O
attempts	O
to	O
make	O
circumvention	O
of	O
these	O
restrictions	O
more	O
difficult	O
.	O
</s>
