Multiple keys for decrypting data in restricted-access television system
First Claim
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1. In a restricted-access television system, the improvement comprising:
- a) transmitting program material in digital packets which are encrypted by first keys which change at a first rate;
b) encrypting the first keys, by second keys which change at a second rate, less than the first;
c) transmitting information in digital packets which allow customers to recover said first keys, through said second keys; and
d) never exposing said keys to external view, outside an integrated circuit.
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Abstract
An encryption system for restricted-access television systems. Multiple decryption keys are used to decrypt encrypted material which is transmitted to customers of a restricted-access television system.
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Citations
1 Claim
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1. In a restricted-access television system, the improvement comprising:
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a) transmitting program material in digital packets which are encrypted by first keys which change at a first rate;
b) encrypting the first keys, by second keys which change at a second rate, less than the first;
c) transmitting information in digital packets which allow customers to recover said first keys, through said second keys; and
d) never exposing said keys to external view, outside an integrated circuit.
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Specification