Method and network for communicating between a group of entities a text encrypted using an encryption key intrinsic to the group of entities in a network having a plurality of entities and a center

• US 5,966,449 A
• Filed: 12/20/1994
• Issued: 10/12/1999
• Est. Priority Date: 12/22/1993
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Yamamoto, Takahisa, Iwamura, Keiichi
• Primary Examiner(s): Hayes, Gail O.
• Assistant Examiner(s): SAYADIAN, HRAYR
• Application Number:
  US08/359,636
• Time in Patent Office: 1,757 Days
• Field of Search: 380/21, 380/49, 380/44
• US Class Current: 380/44
• CPC Class Codes: H04L 9/0847 involving identity based encryption [IBE] schemes

Abstract

In a network having a plurality of entities and a center, the center creates random numbers for all the combinations of two of the entities within the network, and delivers to each entity random numbers created for those combinations involving that entity. A sender entity selects a random number corresponding to the combination of that entity and the destination entity from a group of random numbers delivered to the sender entity, encrypts a communication text using an encryption key determined by the selected random number and sends the encrypted text to the destination entity. The destination entity selects a random number corresponding to the combination of itself and the sender entity from the random numbers delivered to the destination entity, and decodes a cipher text received using an encryption key determined by the selected random number.

Claims

1. A communication method for communication between entities in a network having a plurality of entities and a center, comprising the steps of:

said center converting one-to-one identifiers of the plurality of entities into identification numbers, respectively, in terms of a predetermined function;

said center creating pieces of information which are independent of one another for all combinations composed of two of the identification numbers;

said center delivering to each entity a group of pieces of information created for combinations of two identification numbers involving an identification number obtained by converting an identifier of that entity;

a sender entity converting an identifier of a destination entity into an identification number thereof in terms of the predetermined function, selecting information corresponding to the identification number of said destination entity obtained by conversion from a group of pieces of information delivered to the sender entity, encrypting a communication text using an encryption key depending on the selected information corresponding to the identification number of said destination entity, and sending encrypted text to said destination entity; and

said destination entity receiving the encrypted text, converting an identifier of said sender entity into an identification number thereof in terms of the predetermined function, selecting information corresponding to the identification number of said sender entity obtained by conversion from the group of pieces of information delivered to the destination entity, and decoding the encrypted text using an encryption key depending on the selected information corresponding to the identification number of said sender entity.

2. A method according to claim 1, further comprising the step of storing for each identification number a group of piece information created for all combinations involving that identification number in a memory at an address corresponding to that identification number.

3. A method according to claim 1, wherein said information is a random number of predetermined bits.

4. A method according to claim 3, wherein the encryption key determined by selected information is the selected information itself.

5. A method according to claim 1, wherein said information is information for designating an algorithm.

6. A method according to claim 1, wherein an entity has a plurality of sub-entities, and in the communication between sub-entities, an encryption key is determined by further using intrinsic information between said sub-entities.

7. A method according to claim 6, wherein said intrinsic information is a password determined between specific two entities.

8. A method according to claim 1, wherein an entity has a plurality of sub-entities, and in the communication between sub-entities of specific two entities, an encryption key is determined by further using intrinsic information between said specific two entities.

9. A method according to claim 1, wherein said intrinsic information is an identifier of each sub-entity.

10. A communication method for communication between entities in a network having a plurality of entities and a center, comprising the steps of:

said center converting one-to-one identifiers of said plurality of entities into identification numbers, respectively, in terms of a predetermined function and dividing each of the identification numbers at every nth digit, where n is a predetermined number, to produce portions of those identification numbers;

said center creating pieces of information which are independent of one another for all combinations composed of two numbers from among the portions of the identification numbers;

said center delivering to each entity a group of pieces of information created for combinations of two identification numbers involving the values of portions of the identification number obtained by converting the identifier of that entity, and dividing the converted identification number at every nth digit;

a sender entity converting an identifier of a destination entity into an identification number thereof in terms of the predetermined function, dividing the identification number at every nth digit to produce portions of that identification number, selecting information corresponding to portions of the identification number of said destination entity from a group of pieces of information delivered to the sender entity, encrypting a communication text using an encryption key depending on the selected information corresponding to the portions of the identification number of said destination entity, and sending encrypted text to said destination entity; and

said destination entity receiving the encrypted text, converting an identifier of the sender entity into an identification number thereof in terms of the predetermined function, dividing the identification number at every nth digit to produce portions of that identification number, selecting information corresponding to portions of the identification number of said destination entity from the group of pieces of information delivered to the destination entity and decrypting the encrypted text using an encryption key depending on the selected information corresponding to the portions of the identification number of said sender entity.

11. A method according to claim 10, wherein said information is a random number of predetermined bits.

12. A method according to claim 11, wherein the encryption key determined by selected information is a sum of information selected for a combination of the portions of the identification numbers.

13. A method according to claim 10, wherein said information is information for designating an algorithm.

14. A communication method between groups of a predetermined number of entities in a network having a plurality of entities and a center, comprising the steps of:

said center converting one-to-one identifiers of said plurality of entities into identification numbers, respectively, in terms of a predetermined function;

said center creating pieces of information which are independent of one another for all combinations composed of the predetermined number of the identification numbers;

said center delivering to each entity a group of pieces of information created for combinations of two identification numbers involving an identification number obtained by converting an identifier of a respective entity;

a sender entity converting identifiers of destination entities into respective identification numbers in terms of the predetermined function, selecting information corresponding to a combination of the identification numbers of said destination entities obtained by conversion from a group of pieces of information delivered to the sender entity, encrypting a communication text using an encryption key depending on the selected information corresponding to the identification numbers of said destination entities, and sending encrypted text to said destination entities; and

each of said destination entities receiving the encrypted text converting the identifiers of other entities in the group into respective identification numbers in terms of the predetermined function, selecting information corresponding to a combination of the identification numbers of the other entities obtained by conversion from the group of pieces of information delivered to respective destination entities, and decrypting the encrypted text using an encryption key depending on the selected information corresponding to the-identification numbers of the other entities.

15. A method according to claim 14, further comprising the step of storing for each identification number a group of pieces of information created for all combinations involving that identification number in a memory at an address corresponding to that identification number.

16. A method according to claim 14, wherein said information is a random number of predetermined bits.

17. A method according to claim 16, wherein said encryption key is a random number of predetermined bits which is said selected information.

18. A method according to claim 14, wherein said information is information for designating an algorithm.

19. A communication network having a plurality of entities and a center, wherein said center comprises:

conversion means for converting one-to-one identifiers of said plurality of entities into identification numbers, respectively, in terms of a predetermined function;

creating means for creating pieces of information which are independent of one another for all combinations composed of two of the identification numbers; and

delivering means for delivering to each entity a group of pieces of information created for combinations of two identification numbers involving an identification number obtained by converting an identifier of that entity,

and said each entity comprising;

sender means for converting an identifier of a destination entity into an identification number thereof in terms of the predetermined function, selecting information corresponding to the identification number of the destination entity obtained by conversion from a group of pieces of information delivered to the sender entity, encrypting a communication text using an encryption key depending on the selected information corresponding to the identification number of the destination entity, and sending encrypted text to said destination entity; and

receiver means for receiving the encrypted text, converting an identifier of a sender entity into an identification number thereof in terms of the predetermined function, selecting information corresponding to the identification number of the sender entity obtained by conversion from the group of pieces of information delivered to the destination entity, and decoding the encrypted text using an encryption key depending on the selected information corresponding to the identification number of the sender entity.

20. A network according to claim 19, wherein, for each identification number, a group of pieces of information created for all the combinations involving the identification number for that identification number at an address corresponding to that identification number is stored.

21. A network according to claim 19, wherein said information is random number of predetermined bits.

22. A network according to claim 21, wherein said encryption key determined by selected information is the selected information itself.

23. A network according to claim 22, wherein said information is information for designating an algorithm.

24. A network according to claim 19, wherein an entity has a plurality of sub-entities, and in the communication between sub-entities, an encryption key is determined by further using intrinsic information between said sub-entities.

25. A network according to claim 24, wherein said intrinsic information is an identifier of each sub-entity.

26. A network according to claim 24, wherein said intrinsic information is a password determined between specific two entities.

27. A network according to claim 19, wherein an entity has a plurality of sub-entities, and in the communication between sub-entities of specific two entities, an encryption key is determined by further using intrinsic information between said specific two entities.

28. A network having a plurality of entities and a center, wherein said center comprises:

conversion means for converting one-to-one identifiers of said plurality of entities into identification numbers, respectively, in terms of a predetermined function and dividing each of the identification numbers at every nth digit, where n is a predetermined number;

creating means for creating pieces of information which are independent of one another for all combinations composed of two numbers of the predetermined digits which are portions of identification numbers being divided at every nth digit;

delivering means for delivering to each entity a group of pieces of information created for combinations of two identification numbers involving the values of portions of the identification number obtained by converting the identifier of that entity being divided at every nth digit,

and each said entity comprising;

sender means for converting the identifier of a destination entity into an identification number thereof in terms of the predetermined function, dividing the identification number at every nth digit, selecting information corresponding to the portions of the identification number of said destination entity divided at every nth digit from a group of pieces of information delivered to the sender entity, encrypting a communication text using an encryption key depending on the selected information corresponding to the portions of the identification number of said destination entity, and sending encrypted text to the destination entity; and

receiver means for receiving the encrypted text, converting an identifier of the sender entity into an identification number in terms of said predetermined function, dividing the identification number at every nth digit, selecting information corresponding to portions of the identification number of said destination entity divided at every nth predetermined digit from the group of pieces of information delivered to the destination entity and decoding the encrypted text using an encryption key depending on the selected information corresponding to the portions of the identification number of said sender.

29. A network according to claim 28, wherein said information is a random number of predetermined bits.

30. A network according to claim 29, wherein said encryption key determined by selected information is a sum of information selected for a combination of the portions of the identification numbers.

31. A network according to claim 29, wherein said information is information for designating an algorithm.

32. A network having a plurality of entities and a center, wherein said center comprises:

conversion means for converting one-to-one identifiers of said plurality of entities into identification numbers, respectively, in terms of a predetermined function;

creating means for creating pieces of information which are independent of one another for all combinations composed of a predetermined number of the identification numbers; and

delivering means for delivering to each entity a group of pieces of information created for combinations of two identification numbers involving an identification number obtained by converting the identifier of that entity,

and each said entity comprising;

sender means for converting identifiers of destination entities into respective identification numbers in terms of said predetermined function, selecting information corresponding to a combination of the identification numbers of said destination entities obtained by conversion from a group of pieces of information delivered to the sender entity, encrypting a communication text using an encryption key depending on the selected information corresponding to the identification numbers of said destination entities, and sending encrypted text to the destination entities; and

receiver means for receiving encrypted text, converting the identifiers of other entities within the group into respective identification numbers in terms of said predetermined function, selecting information corresponding to a combination of the identification numbers of those other entities obtained by conversion from the group of pieces of information delivered to respective destination entities, and decoding the encrypted text using an encryption key depending on the selected information corresponding to the identification numbers of the other entities.

33. A network according to claim 32, wherein, for each identification number, a group of pieces of information created for all combinations involving that identification number is stored in a memory means at an address corresponding to that identification number.

34. A network according to claim 32, wherein said information is a random number of predetermined bits.

35. A network according to claim 34, wherein said encryption key is a random number of predetermined bits which is said selected information.

36. A network according to claim 32, wherein said information is information for designating an algorithm.