Data transmission method, data receiving method, data transmission system and program recording medium

Claim 2

A data transmission method comprising the steps of: providing a plurality of types of encryption for each type of data management information; selecting one of the plurality of types of encryption applied to transmission of data depending on a type of data management information for said data to be transmitted; encrypting said data based on said selected type of encryption; and transmitting said encrypted data and said data management information.

Claim 3

A data receiving method comprising the steps of: receiving transmission data transmitted from the data transmission method as set forth in claim 1 ; retrieving said data management information from said received data; and sending said retrieved data management information to the source of said transmitted data and requesting decryption information corresponding to said transmitted data management information.

Claim 4

The data transmission method as set forth in claim 2 , further comprising the step of, transmitting said decryption information corresponding to said data management information to said requesting device.

Claim 5

The data receiving method as set forth in claim 3 , further comprising the steps of: decrypting said received data based on said decryption information and determining how to process said decrypted received data according to said retrieved data management information.

Claim 6

The data receiving method as set forth in claim 2 , wherein sending said data management information is to send said retrieved data management information as is, or to send said retrieved data management information after predetermined conversion.

Claim 7

A program recording medium recording a program for causing a computer to execute all or parts of steps as set forth in claim 2 .

Claim 8

The data transmission method as set forth in claim 1 , wherein determining the type of encryption applied to transmission of said data according to said data management information is to make a key used for encryption different depending on said data management information.

Claim 9

The data transmission method as set forth in claim 1 , wherein determining the type of encryption applied to transmission of said data according to said data management information is to make an algorithm used for encryption different depending on said data management information.

Claim 10

The data transmission method as set forth in claim 1 , wherein said data management information is copy management information which includes information indicating that said data is copy-freely, copy-one-generation, or copy-prohibited.

Claim 11

The data transmission method as set forth in claim 9 , wherein said information indicating copy-prohibited includes two types of information, one indicating that the data is originally copy-prohibited, the other indicating no-more-copies meaning that the data is prohibited for subsequent copy as it is originally copy-one-generation and the one generation is performed, and said type of encryption differs depending on these two types of information.

Claim 12

The data receiving method as set forth in claim 10 , further comprising the step of: in recording data with said information indicating copy-one-generation as the data management information in a predetermined recording medium, changing the content of said data management information from said copy-one-generation to said no-more-copies, and performing said recording together with the data management information indicating said no-more-copies.

Claim 13

The data receiving method as set forth in claim 9 , further comprising the step of: in recording data with said information indicating copy-one-generation as the data management information in a predetermined recording medium, changing the content of said data management information from said copy-one-generation to copy-prohibited, and performing said recording together with the data management information indicating said copy-prohibited.

Claim 14

A program recording medium recording a program for causing a computer to execute all or parts of steps as set forth in claim 1 .

Claim 15

The data transmission method of claim 1 in which encrypting is performed by a plurality of keys, and a key for encrypting one type of encryption for one type of data management information is not common with any other key for encrypting any other type of encryption provided for another type of data management information.

Claim 16

The data transmission method of claim 1 in which encrypting is performed by one of a plurality of keys and a plurality of algorithms, and one of a key and an algorithm for encrypting one type of encryption for one type of data management information is not similar to any other respective key and algorithm for encrypting any other type of encryption provided for another type of data management information.

Claim 17

A data transmission method comprising the steps of: determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted; encrypting said data based on said determined type of encryption; transmitting said encrypted data and said management information; updating said type of encryption by time even if said data management information is identical; encrypting said data to be transmitted with said updated type of encryption; and transmitting previous notification information previously notifying that said update is performed before transmitting said encrypted data.

Claim 18

A data transmission method comprising the steps of: determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted; encrypting said data based on said determined type of encryption; transmitting said encrypted data and said management information; updating said type of encryption by time even if said data management information is identical; encrypting said data to be transmitted with said updated type of encryption; and transmitting previous notification information previously notifying that said update is performed before transmitting said encrypted data.

Claim 19

The data transmission method as set forth in claim 16 , wherein, when said type of encryption is updated by time, said updated type of encryption does not overlap said another type of encryption determined according to said data management information.

Claim 20

The data transmission method as set forth in claim 16 , further comprising the steps of: receiving, by a sink of the transmitted information, said previous notification information; sending by the sink said data management information to a source of said transmitted data according to the previous notification information, and requesting by the sink said decryption information.

Claim 21

A data transmission method comprising the steps of; determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted; encrypting said data based on said determined type of encryption; transmitting said encrypted data and said data management information; updating said type of encryption by time even if said data management information is identical; transmitting information indicating that said update has been performed; and when decryption information corresponding to said data management information is requested, transmitting both decryption information to be used at the moment and decryption information to be used the next time.

Claim 22

A data transmission method comprising the steps of; determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted; encrypting said data based on said determined type of encryption; transmitting said encrypted data and said data management information; updating said type of encryption by time even if said data management information is identical; transmitting information indicating that said update has been performed; and when decryption information corresponding to said data management information is requested, transmitting both decryption information to be used at the moment and decryption information to be used the next time.

Claim 23

The data transmission method as set forth in claim 19 , further comprising the steps of: receiving by a sink of the transmitted information that said update has been performed; and requesting by the sink said decryption information based on the received information.

Claim 24

The data transmission method as set forth in claim 20 , fixer comprising the steps of: in recording data with said management information in which the information indicates copy-one-generation in a predetermined recording medium, changing the content of said data management information from said copy-one-generation to copy-prohibited and performing said recording together with the data management information indicating said copy-prohibited.

Claim 25

The data receiving method as set forth in claim 21 , further comprising the steps of: in recording data wit said management information indicating copy-one-generation, changing the content of said data management information from said copy-one-generation to no-more-copies, and performing said recording together with the data management information indicating said no-more-copies.

Claim 26

The data receiving method as set forth in claim 19 , further comprising the step of, indicating that said update has been performed is received, requesting said decryption information for the source of said information based on the received information.

Claim 27

The data transmission method as set forth in claim 19 , wherein, when said type of encryption is updated by time, said updated type of encryption does not overlap said another type of encryption determined according to said data management information.

Claim 28

A data transmission system comprising: mode determination means of determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted; encryption means of encrypting said data based on said determined type of encryption; data transmission means of transmitting said encrypted data and said data management information; data receiving means of receiving the transmission data transmitted by said data transmission means; data management information retrieving means of retrieving said data management information from said received data; decryption information requesting means of sending said retrieved data management information to a source of said transmitted data and requesting decryption information corresponding to said transmitted data management information; decryption information transmitting means of transmitting said decryption information corresponding to said data management information to said requesting device when said decryption information is requested; decryption means of decrypting said received data based on said decryption information being sent; processing method determination means of determining how to process said decrypted received data according to said retrieved data management information; encryption type updating means of updating said type of encryption by time even if said data management information is identical; and previous notification information generation means of generating previous notification information for previously noting that said update is performed, wherein when said encryption means encrypts data to be transmitted, said encryption means encrypts it according to said updated type of encryption, and said generated previous notification information is transmitted before said data encrypted according to said updated type of encryption is transmitted.

Claim 29

A data transmission system comprising: mode determination means of determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted; encryption means of encrypting said data based on said determined type of encryption; data transmission means of transmitting said encrypted data and said data management information; data receiving means of receiving the transmission data transmitted by said data transmission means; data management information retrieving means of retrieving said data management information from said received data; decryption information requesting means of sending said retrieved data management information to a source of said transmitted data and requesting decryption information corresponding to said transmitted data management information; decryption information transmitting means of transmitting said decryption information corresponding to said data management information to said requesting device when said decryption information is requested; decryption means of decrypting said received data based on said decryption information being sent; processing method determination means of determining how to process said decrypted received data according to said retrieved data management information; encryption type updating means of updating said type of encryption by time even if said data management information is identical; and previous notification information generation means of generating previous notification information for previously noting that said update is performed, wherein when said encryption means encrypts data to be transmitted, said encryption means encrypts it according to said updated type of encryption, and said generated previous notification information is transmitted before said data encrypted according to said updated type of encryption is transmitted.

Claim 30

The data transmission system as set forth in claim 25 , wherein said decryption information requesting means requests said decryption information to said source of said transmitted data in response to said received previous notification information.

Claim 31

The data transmission system as set forth in claim 25 , wherein, when said type of encryption is updated by time, said updated type of encryption does not overlap said another type of encryption determined according to said data management information.

Claim 32

A data transmission system comprising: mode determination means of determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted; encryption means of encrypting said data based on said determined type of encryption; data transmission means of transmitting said encrypted data and said data management information; data receiving means of receiving the transmission data transmitted by said data transmission means; data management information retrieving means of retrieving said data management information from said received data; decryption information requesting means of sending said retrieved data management information to a source of said transmitted data and requesting decryption information corresponding to said transmitted data management information; decryption information transmitting means of transmitting said decryption information corresponding to said data management information to said requesting device when said decryption information is requested; decryption means of decrypting said received data based on said decryption information being sent; processing method determination means of deter g how to process said decrypted received data according to said retrieved data management information; encryption type updating means of updating said type of encrypting by time even if said data management information is identical; and update execution information generation means of generating update information for notifying that said update has been performed, wherein when said encryption meant encrypts data to be transmitted, said encryption means encrypts it according to said updated type of encryption, and said update information is transmitted when the data encrypted according to said updated type of encryption is started to be remitted.

Claim 33

A data transmission system comprising: mode determination means of determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted; encryption means of encrypting said data based on said determined type of encryption; data transmission means of transmitting said encrypted data and said data management information; data receiving means of receiving the transmission data transmitted by said data transmission means; data management information retrieving means of retrieving said data management information from said received data; decryption information requesting means of sending said retrieved data management information to a source of said transmitted data and requesting decryption information corresponding to said transmitted data management information; decryption information transmitting means of transmitting said decryption information corresponding to said data management information to said requesting device when said decryption information is requested; decryption means of decrypting said received data based on said decryption information being sent; processing method determination means of deter g how to process said decrypted received data according to said retrieved data management information; encryption type updating means of updating said type of encrypting by time even if said data management information is identical; and update execution information generation means of generating update information for notifying that said update has been performed, wherein when said encryption meant encrypts data to be transmitted, said encryption means encrypts it according to said updated type of encryption, and said update information is transmitted when the data encrypted according to said updated type of encryption is started to be remitted.

Claim 34

The data transmission system as set forth in claim 28 , wherein said decryption information requesting means requests said decryption information for said source of said transmitted data in response to change of said received update information.

Claim 35

The data transmission system as set forth in claim 28 , wherein, when said type of encryption is updated by time, said updated type of encryption does not overlap said another type of encryption determined according to said data management information.

Claim 36

A data transmission system comprising: mode determination means of determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted in which said type of encryption is one of a plurality of types of encryption provided for each type of management information; encryption means of encrypting said data based on said determined type of encryption; data transmission means of transmitting said encrypted data and said management information; data receiving means of receiving the transmission data transmitted by said data transmission means; data management information retrieving means of retrieving said data management information from said received data; decryption information requesting means of sending said retrieved data management information to the source of said transmitted data and requesting decryption information corresponding to said transmitted data management information; decryption information transmitting means of transmitting said decryption information corresponding to said data management informing to said requesting device when said decryption information is requested; decryption means of decrypting said received data based on said decryption information being sent; and processing method determination means of determining how to process said decrypted received data according to said retrieved data management information.

Claim 37

A data transmission system comprising: mode determination means of determining a type of encryption applied to transmission of data depending on management information for said data to be transmitted in which said type of encryption is one of a plurality of types of encryption provided for each type of management information; encryption means of encrypting said data based on said determined type of encryption; data transmission means of transmitting said encrypted data and said management information; data receiving means of receiving the transmission data transmitted by said data transmission means; data management information retrieving means of retrieving said data management information from said received data; decryption information requesting means of sending said retrieved data management information to the source of said transmitted data and requesting decryption information corresponding to said transmitted data management information; decryption information transmitting means of transmitting said decryption information corresponding to said data management informing to said requesting device when said decryption information is requested; decryption means of decrypting said received data based on said decryption information being sent; and processing method determination means of determining how to process said decrypted received data according to said retrieved data management information.

Claim 38

The data transmission system as set forth in claim 31 , wherein sending said data management information is to send said retrieved data management information as is, or to send said retrieved data management information after predetermined conversion.

Claim 39

The data transmission system as set forth in claim 31 , wherein determining the type of encryption applied to transmission of said data according to said data management information is to make a key used for encryption different depending on said data management information.

Claim 40

The data transmission system as set forth in claim 31 , wherein determining the type of encryption applied to transmission of said data according to said data management information is to make an algorithm used for encryption different depending on said data management information.

Claim 41

The data transmission system as set forth in claim 31 , wherein said data management information is copy management information which includes information indicating that said data is copy-freely, copy-one-generation, or copy-prohibited.

Claim 42

The data transmission system as set forth in claim 35 , wherein said information indicating copy-prohibited includes two types of information, one indicating that the data is originally copy-prohibited, the other indicating no-more-copies meaning that the data is prohibited for subsequent copy as it is originally copy-one-generation and the one generation is performed, and said type of encryption depends on these two types of information.

Claim 43

The data transmission system as set forth in claim 36 , further comprising the step of: when the data management information sent by said data transmission means indicates copy-one-generation, in recording data with said information indicating copy-one-generation as the data management information in a predetermined recording medium, changing the content of said data management information from said copy-one-generation to no-more-copies, and performing said recording together with the data management information indicating no-more-copies.

Claim 44

The data transmission system as set forth in claim 35 , further comprising the step of: when the data management information sent by said data transmission means indicates copy-one-generation, in recording data with said information indicating copy-one-generation as the data management information in a predetermined recording medium, changing the content of said data management information from said copy-one-generation to copy-prohibited, and performing said recording together with the data management information indicating copy-prohibited.

Claim 45

A program recording medium recording a program for causing a computer to execute all or parts of functions of each means as set forth in claim 31 .

Claim 46

The data transmission system of claim 31 in which said encrypting means includes a plurality of keys, and a key for encrypting one type of encryption for one type of management information is not common with any other key for encrypting any other type of encryption provided for another type of management information.

Claim 47

The data transmission system of claim 31 in which said encrypting means includes one of a plurality of keys and a plurality of algorithms, and one of a key and an algorithm for encrypting one type of enctypion for one type of management information is not similar to any other respective key and algorithm for encrypting any other type of encryption provided for another type of management information.