Cryptography – Communication system using cryptography
Reexamination Certificate
2006-08-08
2006-08-08
Revak, Christopher (Department: 2131)
Cryptography
Communication system using cryptography
C380S201000, C380S217000, C380S229000, C380S230000, C380S232000, C726S030000, C726S031000
Reexamination Certificate
active
07088823
ABSTRACT:
A method for controlling access to digital information is performed based on a plurality of decryption keys sent by the information provider. A first type of decryption key instructs a user's host system to reproduce the digital information in accordance with a first level of reproduction quality degradation. Additional keys may specify other degradation levels. The quality of the digital information may be degraded based on a time condition or a use condition. Alternatively, only a portion of the information may be made viewable by a user. In order to obtain full and unrestricted access, the user must obtain a type of decryption key from the provider which removes all previous limitations on reproduction quality degradation.
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Moorthy Aravind K
Revak Christopher
Steinberg William H.
Whitham Curtis Christofferson & Cook PC
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