| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem wherein a software-driven security model is often becomes insecure at execution and requires more processings. <P>SOLUTION: Methods and apparatus are disclosed for setting a processing unit into at least one of a plurality of modes. This apparatus includes a local memory 104, a bus operable to carry information to and from the local memory 104, one or more arithmetic processing units operatively coupled to the local memory 104, and a security circuit operable to set the apparatus into the plurality of operational modes. The plurality of operational modes includes: a first mode whereby the apparatus and an external device are operable to initiate a transfer of information into or out of the memory over the bus; a second mode whereby neither the apparatus nor the external device are operable to initiate the transfer of information into or out of the memory over the bus; and a third mode whereby the apparatus is operable to initiate the transfer of information into or out of the memory over the bus, but the external device is not operable to initiate the transfer of information into or out of the memory over the bus. <P>COPYRIGHT: (C)2009,JPO&INPIT |
