Electrical computers and digital processing systems: support – Data processing protection using cryptography – By stored data protection
Reexamination Certificate
2005-04-19
2005-04-19
Barron, Gilberto (Department: 2132)
Electrical computers and digital processing systems: support
Data processing protection using cryptography
By stored data protection
C380S239000, C380S277000, C705S051000
Reexamination Certificate
active
06883097
ABSTRACT:
A system for protecting content on recordable media for, e.g., DVD audio disks, flash memory media, or other media includes providing a media key block (MKB) on each media, with each MKB including 25,000 encryptions of a media key by 25,000 or so device keys. Each authorized player in the system has a single device key from among the system device keys with which to decrypt the media key. To avoid a coincidence attack in which a hacker can learn the MKB and associated media key and then guess at a device key without knowing its position in the MKB, the media key is XORed with a number representing each position in the MKB, and only then encrypted with the device key corresponding to that position.
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Lotspiech Jeffrey Bruce
Mirles Ariel Virgil
Naor Dalit
Nin Sigfredo Ismael
Barron Gilberto
International Business Machines - Corporation
Lanier Benjamin E.
Rogitz John L.
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