Encrypted digital circuit description allowing signal delay simulation
AssigneeWisconsin Alumni Research Foundation
InventorsParameswaran Ramanathan, Kewal Saluja
Life of this patent
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Abstract
A system for creating protected functional descriptions of integrated circuits provides encrypted gate delay information preventing deduction of gate function from gate delay but allowing simulation of the integrated circuit with accurate propagation delay calculation. Individual gate delay values may be modified so that they obscure actual gate delays but so that the modified individual gate delays total to equal the actual cumulative gate delay along a given data propagation path.
Claims20
An encryptor for digital circuit description files comprising:
- an electronic computer executing a program stored in non-transient medium to:
- (a) receive electronically readable input data defining an underlying digital circuit having multiple interconnected nodes each implementing standard Boolean functions and interconnected between a set of inputs and a set of outputs, the input data describing the interconnection of the nodes, the Boolean functions of the nodes, and actual signal propagation delays associated with the nodes;
- (b) create encrypted output data describing the interconnection of the nodes and providing an encryption of the actual signal propagation delays, the encryption of the actual signal propagation delays permitting computation of cumulative signal propagation delays between the set of inputs and set of outputs without knowledge of the actual signal propagation delays of the nodes;
- and
- (c) output the encrypted output data in a form adapted to permit a simulation of the underlying digital circuit to provide a simulation set of outputs having propagation delays with respect to a simulation set of inputs identical to propagation delays at the set of outputs of the underlying digital circuit receiving the simulation inputs at the set of inputs of the underlying digital circuit.
A method of encrypting a digital circuit file description using an electronic computer executing a program stored in non-transient medium to:
- (a) receive electronically readable input data defining an underlying digital circuit having multiple interconnected nodes each implementing standard Boolean functions and interconnected between a set of inputs and a set of outputs, the input data describing the interconnection of the nodes, the Boolean functions of the nodes, and actual signal propagation delays associated with the nodes;
- (b) create encrypted output data describing the interconnection of the nodes and providing an encryption of the actual signal propagation delays, the encryption of the actual signal propagation delays permitting computation of cumulative signal propagation delays between the set of inputs and set of outputs without knowledge of the actual signal propagation delays of the nodes;
- and
- (c) output the encrypted output data in a form adapted to permit a simulation of the underlying digital circuit to provide a simulation set of outputs having propagation delays with respect to a simulation set of inputs identical to propagation delays at the set of outputs of the underlying digital circuit receiving the simulation inputs at the set of inputs of the underlying digital circuit.
Dependencies are inferred from the claim text.