LSI design method and verification method

Abstract

An encryption process is employed in the LSI design so as to improve confidentiality of the circuit design data over conventional examples. In the encryption process, confidential circuit design data is encrypted to produce encrypted design data and a cipher key. The encrypted design data is provided to the user who conducts a design/verification process. The key is also provided as required. In the design/verification process, the encrypted design data is subjected to various processes without disclosing the contents of the original circuit. In a decoding process, the encrypted design data subjected to the design/verification process is decoded to produce original circuit design data.

1 - 22 . (canceled)  
   
   
       23 . A method for designing an LSI, comprising the step of encrypting provided circuit design data, the encrypting step includes the steps of: 
 generating dummy circuit design data;    converting the circuit design data into encrypted circuit design data by combining the circuit design data and the dummy circuit design data; and    generating key data, wherein the output of the circuit of the circuit design data matches an output of the encrypted circuit when the key data is inputted into the LSI.    
   
   
       24 . A method for designing an LSI, comprising the step of encrypting provided circuit design data, the encrypting step includes the steps of: 
 generating dummy circuit design data;    converting the circuit design data into encrypted circuit design data by combining the circuit design data and the dummy circuit design data; and    generating real key data and dummy key data, wherein the circuit design data is selected to operate as targeted with the real key data and the dummy circuit design data is selected to operate with the dummy key data, the output of the circuit of the circuit design data matches an output of the encrypted circuit when the real key data is inputted into the LSI and the output of the circuit of the circuit design data does not match an output of the encrypted circuit when the dummy key data is inputted into the LSI,    wherein the output of the circuit of the circuit design data matches an output of the encrypted circuit when the real key data is inputted into the LSI after the step of converting the circuit design data into encrypted design data.    
   
   
       25 . A method for designing an LSI, comprising the step of encrypting provided circuit design data, the encrypting step includes the steps of: 
 generating dummy circuit design data having a same number of inputs and a same number of outputs as those of said circuit design data;    converting the circuit design data into encrypted circuit design data by combining the circuit design data and the dummy circuit design data; and    generating key data, wherein the output of the circuit of the circuit design data matches an output of the encrypted circuit when the key data is inputted into the LSI after the step of converting the circuit design data into encrypted circuit design data.