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Secure bootloader for securing digital devices

  • US 7,237,121 B2
  • Filed: 09/17/2001
  • Issued: 06/26/2007
  • Est. Priority Date: 09/17/2001
  • Status: Active Grant
First Claim
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1. A method for ensuring security during the power-on process of a digital device and its contents comprising the steps of:

  • disposing a read only memory storing a bootloader program for control of the programmable data processor, a first read only memory location storing a manufacturer identifier and a second read only memory location storing a device identifier unique to that digital device on a same semiconductor chip as a programmable data processor, the first read only memory location and the second read only memory location not accessible external to the semiconductor chip and not modifiable;

    upon each power-up of the digital device controlling the programmable data processor via the bootloader program to;

    A. read the manufacturer identifier from the first read only memory location;

    B. read the device identifier from the second read only memory location;

    C. compute a first encryption/decryption key using the manufacturer identifier and the device identifier;

    D. read an encrypted second encryption/decryption key from a memory;

    E. decrypt the second encryption/decryption key using the first encryption/decryption key;

    F. read an encrypted program file from a memory;

    G. compute a hashing value for said encrypted program file;

    H. decrypt said encrypted program file using the decrypted second encryption/decryption key;

    I. store said decrypted program file in a memory;

    J. read a hashing value associated with the program file from a memory;

    K. compare said computed hashing value with said read hashing value;

    L. execute said decrypted program file via the programmable data processor if said comparison was equal; and

    M. assert an error message if said comparison was not equal.

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