초록 ▼

A data delivery system providing multipoint delivery of encrypted digital data to specific destinations. A plurality of pieces of key information are generated on the basis of an encryption key specific to each digital data item to be delivered. The multiple pieces of key information are delivered o

A data delivery system providing multipoint delivery of encrypted digital data to specific destinations. A plurality of pieces of key information are generated on the basis of an encryption key specific to each digital data item to be delivered. The multiple pieces of key information are delivered over routes which differ from the routes used to deliver the digital data and which further differ from each other. Physically different media or transmission over a network at different times are used to separately transmit different sets of key information.

대표청구항 ▼

What is claimed is: 1. A digital data delivery method for use in delivering digital data from an upstream system to a downstream system, said upstream system providing multipoint delivery of encrypted digital data to specific destinations, and said downstream system decrypting the delivered digital

What is claimed is: 1. A digital data delivery method for use in delivering digital data from an upstream system to a downstream system, said upstream system providing multipoint delivery of encrypted digital data to specific destinations, and said downstream system decrypting the delivered digital data, said method comprising the steps of: encrypting digital data at said upstream system using an encryption key; generating on the basis of said encryption key, sets of passkeys, each set having at least two passkeys and each set of passkeys specific to a respective one of said specific destinations by dividing said encryption key by a division pattern that is: (a) unique to each of said specific destinations and (b) based on the content of said digital data; generating a plurality of partial keys based on a portion of the passkeys in said set or a portion of passkey information from which said passkeys may be reproduced; delivering either said plurality of partial keys or partial key information, from which said partial keys may be reproduced, and delivering the remaining passkeys in a set not used to generate said partial keys or the remaining passkey information, to a respective one of said specific destinations over a plurality of delivery routes which differ from routes for delivering said digital data and which are further different from each other; delivering the encrypted digital data; restoring said encryption key by using said downstream system using either said plurality of partial keys or said partial key information and using either said remaining passkeys or said remaining passkey information in a set delivered over said plurality of delivery routes; and using the restored encryption key to decrypt the encrypted digital data. 2. The method of claim 1, wherein a set of said partial keys is generated by dividing a portion of said set of passkeys specific to a destination by a predetermined division pattern specific to the destination of said set of partial keys. 3. A signal processing method for use with an upstream system providing multipoint delivery of encrypted digital data to specific destinations, said method comprising the steps of: encrypting digital data at said upstream system using an encryption key; generating on the basis of said encryption key, sets of passkeys, each set having at least two passkeys and each set of passkeys specific to a respective one of said specific destinations by dividing said encryption key by a division pattern that is: (a) unique to each of said specific destinations and (b) based on the content of said digital data; generating a plurality of partial keys based on a portion of the passkeys in said set or a portion of passkey information from which said passkeys may be reproduced; delivering either said plurality of partial keys or partial key information, from which said partial keys may be reproduced, and delivering the remaining passkeys in a set not used to generate said partial keys or the remaining passkey information, to a respective one of said specific destinations over a plurality of delivery routes which differ from routes for delivering said digital data and which are further different from each other; and delivering the encrypted digital data. 4. The method of claim 3 wherein a set of said partial keys is generated by dividing a portion of said set of passkeys specific to a destination by a predetermined division pattern specific to the destination of said set of partial keys. 5. A digital data delivery system comprising an upstream system providing multipoint delivery of encrypted digital data to specific destinations and a downstream system decrypting the delivered digital data; said upstream system including: an encrypting element for encrypting digital data using an encryption key; a first key information generator for generating, on the basis of said encryption key, sets of passkeys, each set having at least two passkeys and each set of passkeys specific to a respective one of said specific destinations by dividing said encryption key by a division pattern that is: (a) unique to each of said specific destinations and (b) based on the content of said digital data; a second key information generator for generating a plurality of partial keys based on a portion of the passkeys in said set or a portion of passkey information, from which said passkeys may be reproduced; a key information delivery element for delivering either said plurality of partial keys or partial key information, from which said partial keys may be reproduced, and for delivering the remaining passkeys in a set not used to generate said partial keys or the remaining passkey information, to a respective one of said specific destinations over a plurality of delivery routes which differ from routes for delivering said digital data and which are further different from each other; and a digital data delivery element for delivering the encrypted digital data; and said downstream system including: an encryption key restoring element for restoring said encryption key using either said plurality of partial keys or said partial key information and using either said remaining passkeys or said remaining passkey information in a set delivered over said plurality of delivery routes; and a decrypting element for decrypting the encrypted digital data using the restored encryption key. 6. An upstream system for providing multipoint delivery of encrypted digital data to specific destinations, comprising: an encrypting element for encrypting digital data using an encryption key; a first generator for generating on the basis of said encryption key, sets of passkeys, each set having at least two passkeys and each set of passkeys specific to a respective one of said specific destinations by dividing said encryption key by a division pattern that is: (a) unique to each of said specific destinations and (b) based on the content of said digital data; a second generator for generating a plurality of partial keys based on a portion of the passkeys in said set or a portion of passkey information from which said passkeys may be reproduced; a key information delivery element for delivering either said plurality of partial keys or partial key information, from which said partial keys may be reproduced, and delivering the remaining passkeys in a set not used to generate said partial keys or the remaining passkey information, to a respective one of said specific destinations over a plurality of delivery routes which differ from routes for delivering said digital data and which are further different from each other; and a digital data delivery element for delivering the encrypted digital data. 7. The system of claim 6, wherein said second key information generator generates a set of said partial keys by dividing a portion of said set of passkeys specific to a destination by a predetermined division pattern specific to the destination of said set of partial keys. 8. A storage medium which stores a computer-readable program for controlling the steps of: encrypting digital data using an encryption key; generating on the basis of said encryption key, sets of passkeys, each set having at least two passkeys and each set of passkeys specific to a respective one of specific destinations by dividing said encryption key by a division pattern that is: (a) unique to each of said specific destinations and (b) based on the content of said digital data; generating a plurality of partial keys based on a portion of the passkeys in said set or a portion of passkey information from which said passkeys may be reproduced; delivering either said plurality of partial keys or partial key information, from which said partial keys may be reproduced, and delivering the remaining passkeys in a set not used to generate said partial keys or the remaining passkey information, to a respective one of said specific destinations over a plurality of delivery routes which differ from routes for delivering said digital data and which are further different from each other; and performing multipoint delivery of the encrypted digital data to said specific destinations. 9. The storage medium of claim 8, wherein a set of said partial keys is generated by dividing a portion of said set of passkeys specific to a destination by a predetermined division pattern specific to the destination of said set of partial keys.