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1829 Dec 2015 - 17:40ThomasMisa 
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You are here: UMWiki>CBI_ComputerSecurity Web>Systems>SystemsBlacker (revision 17)

Current Activitieslock Who is Who?lock People Programs Publications CSHW_2014 Systems Events Mechanisms



BLACKER was the first wide-area computer-network security project -- and only the second or third system of any kind -- to achieve the "top" Trusted Computer System Evaluation Criteria (TCSEC) A1 rating, which it earned in 1991. (Boeing's Secure Local Area Network was also so designated in 1991.) A U.S. Department of Defense project conducted jointly by System Development Corporation and Burroughs, BLACKER was the first end-to-end trusted encryption system on the U.S. Defense Data Network (DDN).(1)

Four elements of the system were developed by the military systems division of Unisys. (In 1980 SDC had been sold to Burroughs, and in 1986 Burroughs and Sperry merged to form Unisys.) (1) The BLACKER front end (BFE) was an encryption box that sat between the host computer and the packet switched network. (2) The BLACKER initialization-parameters carrier (BIC), a "cigarette-box sized" removable device, provided host-specific operational and security parameters. The two other devices on the network (3-4) controlled the permissions for message exchange (this Access Control Center was described as the "brains" of the system) and distributed security keys (Key Distribution Center). There were provisions for 50 secure hosts per backbone and up to 1,000 hosts per domain, with internetworking allowing a system of up to 50,000 hosts.(2)

BLACKER employed the Bell-LaPadula security model, where a host computer served as a "subject," and the encrypted network was the "object." However, applying the highly logical Bell-LaPadula model to networked security was not straightforward. These difficulties pointed to limitations in the Bell-LaPadula model in computer security.(3) (4)

BLACKER was implemented on the DDN using Cisco Systems X.25. The front-end encryption (BFE) allowed host computers to communicate securely over unsecured packet-switched networks. The virtual network between the BFE-secured machines was called the "red" network. The packet-switched network, carrying both the secured BFE traffic as well as unsecured traffic, was called the "black" network.(5)

Blacker DDN diagram (from Weissman 1992):


1 , 4 : Donald MacKenzie, Mechanizing Proof: Computing, Risk, and Trust (MIT Press, 2001), 181, 190-191.

2 : lock Clark Weissman, BLACKER: Security for the DDN Examples of A1 Security Engineering Trades IEEE Computer Society Symposium on Research in Security and Privacy (IEEE, 1992), 286. (Login required)

3 : lock Clark Weissman, BLACKER: Security for the DDN Examples of A1 Security Engineering Trades IEEE Computer Society Symposium on Research in Security and Privacy (IEEE, 1992), 287. (Login required)

5 : lock Emil V. DeRenzo, et al, The Integrated Tactical Data Network (ITDN): Multi-Security Level Tactical/Strategic Connectivity Through Existing Packet Switching Technology Military Communications Conference, 1990. MILCOM Conference Record, A New Era (IEEE, 1990), 2-4, 6. (Login required)

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Topic revision: r17 - 29 Dec 2015 - 17:39:31 - ThomasMisa
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