| 摘要 |
A programmable electronic device ( 10 ) stores a number of cipher-text software modules ( 14 ) to which access is granted after evaluating a user's token ( 55, 80, 82 ), a software-restriction class ( 58 ) for a requested software module ( 14 ), and/or a currently active access-control model ( 60 ). Access-control models ( 60 ) span a range from uncontrolled to highly restrictive. Models ( 60 ) become automatically activated and deactivated as users are added to and deleted from the device ( 10 ). A virtual internal user proxy that does not require users to provide tokens ( 80, 82 ) is used to enable access to modules ( 16 ) classified in a global software-restriction class ( 62 ) or when an uncontrolled-access-control model ( 68 ) is active. Both licensed modules ( 76 ) and unlicensed modules ( 18,78 ) may be loaded in the device ( 10 ). However, no keys are provided to enable decryption of unlicensed modules ( 18,78 ).
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