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Библиогр.: 7 назв.

Inserting malicious sub-circuits that may cause a
circuit failure or lead to theft of confidential information from a
system containing the logical circuit demands detection of such
sub-circuits followed by their masking if possible. We propose an
approach to selection of nodes in sequential circuit, where
insertion of Trojan Circuit (TC) is likely. The method is based on
applying precise (not heuristic) probabilistic calculations of
controllability and observability of combinational part internal
nodes and algorithms of a transfer sequence detection for a set of
internal states. Note that TC may be inserted in an internal node
out of working area (don’t care set) represented by State
Transition Graph (STG). The out of working area states are
compactly represented by Reduced Ordered Binary Decision
Diagram (ROBDD) that is derived when the precise estimations
are being calculated. ROBDD operations characterizing by
polynomial complexity are used both for calculation of precise
controllability and observability estimations and detection of
transfer sequence. As the suggested approach considers facilities
of inserting TCs out of the working area, they cannot be detected
both under verification and testing in the working area (care set).
The technique of masking TCs with rather small overhead is
proposed. The experimental results on MCNC benchmarks
illustrate applicability of the approach.