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Methods and apparatus for secure data processing and transmission

  • US 7,502,928 B2
  • Filed: 11/12/2004
  • Issued: 03/10/2009
  • Est. Priority Date: 11/12/2004
  • Status: Active Grant
First Claim
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1. An apparatus, comprising:

  • a local memory;

    a bus operable to carry information to and from the local memory;

    one or more arithmetic processing units operable to process data and operatively coupled to the local memory; and

    a security circuit including a secret data area that is not accessible by devices outside the security circuit, the secret data area containing a first key and a second key, and the security circuit includes an accessible data area that is accessible by devices outside the security circuit, the security circuit being operable to;

    place the apparatus into any of a plurality of operational modes, wherein the plurality of operational modes includes at least;

    (i) a first mode whereby the apparatus and an external device are operable to initiate a transfer of information into or out of the local memory over the bus,(ii) a second mode whereby neither the apparatus nor the external device are operable to initiate a transfer of information into or out of the memory over the bus, and(iii) a third mode whereby the apparatus is operable to initiate a transfer of information into or out of the local memory over the bus, but the external device is not operable to initiate a transfer of information into or out of the local memory over the bus; and

    place a copy of the first key in the accessible data area when the apparatus is in the second mode.

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