Method and apparatus for uniquely encrypting a plurality of services at a transmission site
First Claim
1. In a communications system wherein a plurality of services are to be transmitted from a transmission site to a reception site, a method for uniquely encrypting each service at the transmission site comprising the steps of:
- a) generating a unique spreading function for each service to be transmitted, wherein each unique spreading function comprises a unique N-bit quantity;
b) generating a random quantity;
c) for each service, (i) convolving the random quantity with the spreading function generated for that service in step (a) to produce a unique encryption seed for that service, and (ii) encrypting at least a portion of that service in accordance with an encryption algorithm upon the encryption algorithm being keyed with the unique encryption seed; and
d) transmitting the random quantity to the reception site along with said encrypted portions of each service, but not transmitting the unique encryption seeds produced for each service in step (c)(i).
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Accused Products
Abstract
Methods and apparatus are described for uniquely encrypting a plurality services at a transmission site and for decrypting selected services at a reception site while reducing the amount of encryption related information that must be transmitted to the reception site for decryption purposes. A unique spreading function is generated at the transmission site for each service to be transmitted. A random quantity is then transmitted, and the random quantity is convolved with each spreading function to produce a unique encryption seed for each service. At least a portion of each service is then encrypted using the unique encryption seeds produced for each service. Only the random quantity is transmitted to the reception site along with the encrypted portions of each service. None of the unique encryption seeds are transmitted. At the reception site, the unique spreading functions generated at the transmission site for each service are regenerated. A selected service is then decrypted by (i) convolving the received random quantity with the regenerated spreading function associated with the selected service to reproduce the unique encryption seed used to encrypt the received encrypted portion of the selected service at the transmission site, and (ii) decrypting the received encrypted portion of the selected service using the reproduced encryption seed. By transmitting only the random quantity, and then reproducing the encryption seeds at the reception site, the amount of encryption related information transmitted to the reception site is greatly reduced.
201 Citations
17 Claims
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1. In a communications system wherein a plurality of services are to be transmitted from a transmission site to a reception site, a method for uniquely encrypting each service at the transmission site comprising the steps of:
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a) generating a unique spreading function for each service to be transmitted, wherein each unique spreading function comprises a unique N-bit quantity; b) generating a random quantity; c) for each service, (i) convolving the random quantity with the spreading function generated for that service in step (a) to produce a unique encryption seed for that service, and (ii) encrypting at least a portion of that service in accordance with an encryption algorithm upon the encryption algorithm being keyed with the unique encryption seed; and d) transmitting the random quantity to the reception site along with said encrypted portions of each service, but not transmitting the unique encryption seeds produced for each service in step (c)(i). - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a communications system wherein a plurality of encrypted services are transmitted from a transmission site to a reception site, and wherein each of said services was uniquely encrypted at the transmission site by (i) generating a unique spreading function for each service, each spreading function comprising a unique N-bit quantity, (ii) generating a random quantity, (iii) independently convolving the random quantity with the spreading function generated for each service to produce a unique encryption seed for each service, and then (iv) encrypting each service in accordance with an encryption algorithm upon the encryption algorithm being keyed with the respective unique encryption seed produced for that service, and further wherein only the random quantity, and not each of the unique encryption seeds, is transmitted to the reception site along with the encrypted services, a method of decrypting a selected service at the reception site comprising the steps of:
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a) receiving the random quantity and the encrypted services from the transmission site; b) selecting one of said received encrypted services for decryption; c) regenerating at the reception site, in a manner identical to that performed at the transmission site, the unique spreading function generated at the transmission site for the selected service; d) convolving, in a manner identical to that performed at the transmission site, the regenerated spreading function with the received random quantity to reproduce, at the reception site, the unique encryption seed produced at the transmission site and used at the transmission site to key said encryption algorithm in order to encrypt the selected received encrypted service; and e) decrypting the selected received encrypted service using the reproduced encryption seed.
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9. An encryption apparatus for uniquely encrypting a plurality of services at a transmission site and for transmitting the encrypted services to a remote reception site comprising:
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spreading function generator means for generating a spreading function for each of said services to be transmitted, each spreading function comprising a unique N-bit quantity and being associated with a respective one of said services; a random signal generator for generating a random quantity; seed generator means electrically coupled to the random signal generator and to the spreading function generator means for independently convolving the random quantity with each of the spreading functions generated by the spreading function generator means to produce a unique encryption seed for each respective service; a plurality of service encryptors each electrically coupled to the seed generator means and each electrically coupled to receive a respective one of said services for encrypting the respective service in accordance with an encryption algorithm upon said encryption algorithm being keyed by the unique encryption seed produced for that respective service; and a transmitter electrically coupled to the service encryptors and to the random signal generator for transmitting the random quantity and each of the encrypted services to a remote reception site, but not transmitting the unique encryption seeds produced by the seed generator means. - View Dependent Claims (10, 11, 12, 13)
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14. A decryption apparatus for use at a reception site in a communications system wherein a plurality of encrypted services are transmitted from a transmission site to the reception site, and wherein each of said services is uniquely encrypted by an encryption apparatus at the transmission site by (i) generating a unique spreading function for each service, each unique spreading function comprising a unique N-bit quantity, (ii) generating a random quantity, (iii) independently convolving the random quantity with the spreading function generated for each service to produce a unique encryption seed for each service, and then encrypting each service in accordance with an encryption algorithm upon said encryption algorithm being keyed with the respective unique encryption seed produced for that service, and further wherein only the random quantity, and not each of the unique encryption seeds, is transmitted to the reception site along with the encrypted services, said decryption apparatus comprising:
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a receiver for receiving the random quantity and the encrypted services from the transmission site; a selection switch for selecting one of said received encrypted services for decryption; a spreading function generator for regenerating, in a manner identical to that performed at the transmission site by the encryption apparatus, the unique spreading function generated by the encryption apparatus for the selected service; a seed generator electrically coupled to the receiver and to the spreading function generator for convolving, in a manner identical to that performed at the transmission site by the encryption apparatus, the regenerated spreading function with the received random quantity to reproduce the unique encryption seed produced by the encryption apparatus and used to key said encryption algorithm in order to encrypt the selected received encrypted service; and a service decryptor electrically coupled to the receiver and to the seed generator for decrypting the selected received encrypted service using the reproduced encryption seed. - View Dependent Claims (15, 16, 17)
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Specification