<s>
Dynamic	B-Application
Network	I-Application
Authentication	I-Application
System	I-Application
(	O
DNAS	B-Application
)	O
was	O
a	O
proprietary	O
authentication	O
system	O
created	O
by	O
Sony	O
Computer	O
Entertainment	O
Inc	O
made	O
for	O
the	O
Playstation	B-Device
2	I-Device
,	O
Playstation	B-Operating_System
Portable	I-Operating_System
,	O
and	O
PSX	B-Device
(	O
digital	O
video	O
recorder	O
)	O
.	O
</s>
<s>
DNAS	B-Application
retrieved	O
information	O
about	O
a	O
user	O
's	O
hardware	O
and	O
software	O
for	O
authentication	O
,	O
copy	B-Application
protection	I-Application
,	O
account	O
blocking	O
,	O
system	O
,	O
rules	O
,	O
or	O
game	O
management	O
and	O
other	O
purposes	O
.	O
</s>
<s>
DNAS	B-Application
used	O
a	O
set	O
of	O
codes	O
in	O
a	O
protected	O
area	O
of	O
the	O
game	O
DVD	O
together	O
with	O
serial	O
numbers	O
from	O
the	O
console	O
EEPROM	B-General_Concept
for	O
online	O
authentication	O
.	O
</s>
<s>
Some	O
games	O
have	O
a	O
double	O
DNAS	B-Application
check	O
to	O
prevent	O
people	O
from	O
patching	O
them	O
.	O
</s>
<s>
The	O
DNAS	B-Application
service	O
was	O
terminated	O
on	O
4	O
April	O
2016	O
for	O
NTSC/U	O
and	O
PAL	O
regions	O
after	O
the	O
last	O
official	O
online	O
game	O
,	O
Final	B-Protocol
Fantasy	I-Protocol
XI	I-Protocol
,	O
was	O
taken	O
offline	O
on	O
31	O
March	O
2016	O
,	O
but	O
continued	O
to	O
support	O
NTSC/J	O
PS2	B-Device
titles	O
and	O
the	O
Playstation	O
Store	O
on	O
the	O
Playstation	B-Operating_System
Portable	I-Operating_System
.	O
</s>
<s>
However	O
unofficial	O
private	O
servers	O
allowed	O
game	O
play	O
on	O
other	O
PS2	B-Device
games	O
until	O
4	O
April	O
.	O
</s>
