Scientific-Atlanta, Inc.

Michael S Palgon

Howard G Pinder

Glendon Leo Akins, Iii

Anthony John Wasilewski

Robert O Banker

A cable television system provides conditional access to services. The cable television system includes a headend from which service 'instances', or programs, are broadcast and a plurality of set top units for receiving the instances and selectively decrypting the instances for display to system subscribers. The service instances are encrypted using public and/or private keys provided by service providers or central authorization agents. Keys used by the set tops for selective decryption may also be public or private in nature, and such keys may be reassigned at different times to provide a cable television system in which piracy concerns are minimized.

Representing entitlements to service in a conditional access system

A cable television system provides conditional access to services. The cable television system includes a headend from which service &ldquo;instances&rdquo;, or programs, are broadcast and a plurality of set top units for receiving the instances and selectively decrypting the instances for display to system subscribers. The service instances are encrypted using public and/or private keys provided by service providers or central authorization agents. Keys used by the set tops for selective decryption may also be public or private in nature, and such keys may be reassigned at different times to provide a cable television system in which piracy concerns are minimized.

Source authentication of download information in a conditional access system

A cable television system provides conditional access to services. The cable television system includes a headend from which service &ldquo;instances&rdquo;, or programs, are broadcast and a plurality of step top units for receiving the instances and selectively decrypting the instances for display to system subscribers. The service instances are encrypted using public and/or private keys provided by service providers or central authorization agents. Keys used by the set tops for selective decryption may also be public or private in nature, and such keys may be reassigned at different times to provide a cable television system in which piracy concerns are minimized.

Conditional access system

Encryption devices for use in a conditional access system

Verification of the source of program information in a conditional

A method of encrypting clear payload data to form encrypted payload data uses a block cipher, the block cipher being characterized by a predetermined block length. The method includes a step of parsing and first and second steps of encrypting. The step of parsing parses the clear payload data into at least one full clear block and a residual block, the at least one full clear block including a last full clear block. Each full clear block is characterized by the predetermined block length. The residual block is characterized by a residual block length, the residual block length being less than the predetermined block length. The step of parsing further parses the last full clear block into a first part and a second part, the second part being characterized by a length equaling a difference between the predetermined block length and the residual block length. The first step of encrypting encrypts a combination of the second part and the residual block to form a first encrypted block, the first encrypted block having a third part and a fourth part. The third part is characterized by a length equaling the second part length. The second step of encrypting encrypts a combination of the first part and the third part to form a second encrypted block, and it is the combination of the second encrypted block and the fourth part that forms the encrypted payload data.

Growing community of inventors

Atlanta, GA, United States of America

Michael S Palgon