Patent ID: 7203958

Claim:
A program use authorization method for authorizing the use of programs on a computer, using a memory medium connected to the computer, the method comprising: accepting an input of an install key generated on the basis of first and second codes specific to each program; sending the first code contained in the install key to the memory medium, and receiving a first encrypted code generated by encrypting the first code by the memory medium; reading out a second encrypted code generated by encrypting the second code by the first code and stored in the memory medium; and executing installation authorization regarding authorization/rejection of the program installation on the basis of the relationship between the install key and the second encrypted code; wherein the install key is a combination of the first code and the second encrypted code; and the executing installation authorization includes decrypting the second encrypted code contained in the install key, and the second encrypted code read out from the memory medium, into second codes using the received first encrypted code, and determining agreement/disagreement between the two decrypted second codes.