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System and method for controlled copying and moving of content between devices and domains based on conditional encryption of content key depending on usage state

  • US 7,844,821 B2
  • Filed: 08/27/2008
  • Issued: 11/30/2010
  • Est. Priority Date: 10/18/2001
  • Status: Expired due to Fees
First Claim
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1. A method, comprising:

  • receiving a voucher at an apparatus from a further apparatus;

    computing a cryptographic hashing function over at least part of the voucher;

    decrypting an encrypted hash value stored in the voucher with a public key of the further apparatus; and

    comparing the computed hash value with the stored hash value,wherein the voucher contains an encrypted content key, a usage state record, and a domain traversal flag, wherein the usage state record enforces play limits,wherein all apparatuses in an authorized domain have ability to decrypt the encrypted content key, andwherein said all apparatuses in the authorized domain are apparatuses of one or more of a user and a family.

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