<s>
Blacker	B-General_Concept
(	O
styled	O
BLACKER	B-General_Concept
)	O
is	O
a	O
U.S.	O
Department	O
of	O
Defense	O
computer	O
network	O
security	O
project	O
designed	O
to	O
achieve	O
A1	O
class	O
ratings	O
(	O
very	O
high	O
assurance	O
)	O
of	O
the	O
Trusted	O
Computer	O
System	O
Evaluation	O
Criteria	O
(	O
TCSEC	O
)	O
.	O
</s>
<s>
The	O
first	O
Blacker	B-General_Concept
program	O
began	O
in	O
the	O
late	O
1970s	O
,	O
with	O
a	O
follow-on	O
eventually	O
producing	O
fielded	O
devices	O
in	O
the	O
late	O
1980s	O
.	O
</s>
