Simultaneous electronic transactions

• US 6,134,326 A
• Filed: 04/02/1997
• Issued: 10/17/2000
• Est. Priority Date: 11/18/1996
• Status: Expired due to Term

• Current Assignee: Silvio Micali
• Original Assignee: Bankers Trust Corporation
• Inventors: Micali, Silvio
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/832,071
• Time in Patent Office: 1,294 Days
• Field of Search: 380/30, 380/282, 380/285, 455/899
• US Class Current: 380/30
• CPC Class Codes: G06F 2211/008 Public Key, Asymmetric Key, Asymmetric Encryption
• CPC Class Codes: G06F 2211/009 Trust
• CPC Class Codes: G06Q 20/00 Payment architectures, schemes or protocols apparatus for performing or posting payment transactions G07F7/08, G07F19/00; electronic cash registers G07G1/12
• CPC Class Codes: G06Q 20/02 involving a neutral party, e.g. certification authority, notary or trusted third party [TTP]
• CPC Class Codes: G06Q 20/341 Active cards, i.e. cards including their own processing means, e.g. including an IC or chip
• CPC Class Codes: G06Q 20/389 Keeping log of transactions for guaranteeing non-repudiation of a transaction
• CPC Class Codes: G06Q 20/40975 using encryption therefor
• CPC Class Codes: G07F 7/1008 Active credit-cards provided with means to personalise their use, e.g. with PIN-introduction/comparison system
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2463/102 applying security measure for e-commerce
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 9/321 involving a third party or a trusted authority
• CPC Class Codes: H04L 9/3218 using proof of knowledge, e.g. Fiat-Shamir, GQ, Schnorr, ornon-interactive zero-knowledge proofs
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

A communication method between a first and second party, in the presence of a trusted party, that enables a transaction in which the second party receives a first value produced by the first party and unpredictable to the second party if and only if the first party receives a second value produced by the second party and unpredictable to the first party. The method includes two basic steps: exchanging a first set of communications between the first and second parties without participation of the trusted party to attempt completion of the transaction, and if the transaction is not completed using the first set of communications between the first and second parties, having the trusted party take action to complete the transaction.

Claims

1. A method of communicating between a first and second party, comprising the steps of:

initiating an exchange of messages between the first and second parties without intervention of a trusted third party; and

in response to one of the first and second parties not receiving at least one of the messages from an other one of the first and second parties, having the trusted third party take action to provide appropriate messages to the first and second parties.

2. An electronic communication method comprising:

sending from a first party a first message to be received by a second party without intervention by a trusted third party, at least some of the contents of the first message being unintelligible to the second party;

receiving by the first party a second message from the second party verifying that the second party received the first message; and

sending from the first party a third message enabling the second party to understand the contents of the first message unintelligible to the second party;

wherein the at least some of the contents are able to be rendered intelligible to the second party through assistance of the first party, and

the at least some of the contents are able to be rendered intelligible to the second party through assistance of the trusted third party.

3. The electronic communication method of claim 2, further comprising generating, by the first party, the first message using information not known by the second party.

4. The electronic communication method of claim 2, wherein the first message includes a valid digital signature by the first party of at least some of the contents unintelligible to the second party.

5. The electronic communication method of claim 2, wherein the first message includes information indicating the first party is involved in the message.

6. The electronic communication method of claim 2, wherein the first message includes information indicating the second party is involved in the message.

7. The electronic communication method of claim 2, wherein the second message has a portion unpredictable to the first party.

8. The electronic communication method of claim 2, wherein the second message includes a valid signature of the second party of information representative of the first message.

9. An electronic communication method comprising:

sending from a first party a first message to be received by a second party without intervention by a trusted third party, at least some of the contents of the first message being unintelligible to the second party; and

receiving by the first party a second message from the trusted third party, the second message verifying that the second party received the first message;

wherein the at least some of the contents are able to be rendered intelligible to the second party through assistance of the first party, and

the at least some of the contents are able to be rendered intelligible to the second party through assistance of the trusted third party.

10. The electronic communication method of claim 9, further comprising generating, by the first party, the first message using information not known by the second party.

11. The electronic communication method of claim 9, wherein the first message includes a valid digital signature by the first party of at least some of the contents unintelligible to the second party.

12. The electronic communication method of claim 9, wherein the first message includes information indicating the first party is involved in the message.

13. The electronic communication method of claim 9, wherein the first message includes information indicating the second party is involved in the message.

14. The electronic communication method of claim 9, wherein the second message has a portion unpredictable to the first party.

15. The electronic communication method of claim 9, wherein the second message includes a valid signature of the second party of information representative of the first message.

16. The electronic communication method of claim 9, wherein at least a part of the first message is unintelligible to the trusted third party.

17. The electronic communication method of claim 9, wherein the second message is based on information not known by the trusted third party.

18. The electronic communication method of claim 9, wherein at least a part of the second message is unintelligible to the trusted party.

19. The electronic communication method of claim 9, further comprising receiving, by the first party after sending the first message and before receiving the second message, a third message.

20. The electronic communication method of claim 19, wherein:

the third message verifies receipt of the first message by the second party; and

the first party sends no other messages to the second party before receiving the second message.

21. The electronic communication method of claim 19, wherein the third message does not verify receipt of the first message by the second party.

22. The electronic communication method of claim 21, wherein the third message does not verify receipt of the first message by the second party because it does not include a valid signature by the second party of information representative of the first message.

23. The electronic communication method of claim 22, further comprising determining, by the first party, that a signature in the third message is not a valid signature of the second party.

24. The electronic communication method of claim 22, further comprising determining, by the first party, that a signature in the third message is not a signature of a given portion of the first message.

25. The electronic communication method of claim 24, further comprising sending, by the first party after sending the first message and before receiving the second message, a third message to be received by the second party, where the third message does not satisfy a predetermined criterion.

26. The electronic communication method of claim 25, wherein the predetermined criterion is one of that the third message enables intelligible disclosure of the contents of the first message unpredictable to the second party.

27. The electronic communication method of claim 25, wherein the predetermined criterion is that the third message does not include a valid signature of information representative of the contents of the first message unpredictable to the second party.

28. An electronic communication method comprising:

receiving by a first party a first message from a second party without intervention of a trusted third party, at least some of the contents of the first message being unintelligible to the first party;

sending by the first party a second message verifying that the first party received the first message; and

receiving by the first party a third message from the second party enabling the first party to understand the contents of the first message unintelligible to the first party;

wherein the at least some of the contents are able to be rendered intelligible to the first party through assistance of the second party, and

the at least some of the contents are able to be rendered intelligible to the first party through assistance of the trusted third party.

29. The electronic communication method of claim 28, wherein the first message includes a valid digital signature by the second party of at least some of the contents unintelligible to the first party.

30. The electronic communication method of claim 28, wherein the first message includes information indicating the second party is involved in the message.

31. The electronic communication method of claim 28, wherein the first message includes information indicating the first party is involved in the message.

32. The electronic communication method of claim 28, wherein the second message has a portion unpredictable to the second party.

33. The electronic communication method of claim 28, wherein the second message includes a valid signature of the first party of information representative of the first message.

34. An electronic communication method comprising:

receiving by a first party a first message from a second party without intervention of a trusted third party, at least some of the contents of the first message being unintelligible to the first party;

sending by the first party a second message to the trusted third party, the second message verifying that the first party received the first message; and

receiving by the first party a third message from the trusted third party, the third message enabling the first party to understand the contents of the first message unintelligible to the first party;

wherein the at least some of the contents are able to be rendered intelligible to the first party through assistance of the second party, and

the at least some of the contents are able to be rendered intelligible to the first party through assistance of the trusted third party.

35. The electronic communication method of claim 34, wherein the first message is based on information not known by the first party.

36. The electronic communication method of claim 34, wherein at least a part of the second message is unpredictable to the trusted third party.

37. The electronic communication method of claim 34, wherein the second message is based on information not known by the trusted third party.

38. The electronic communication method of claim 34, further comprising sending, by the first party after receiving the first message and before receiving the trusted third message, a fourth message to the second party.

39. The electronic communication method of claim 38, wherein:

the fourth message verifies receipt of the first message by the first party; and

the first party receives no other messages from the second party before receiving the trusted third message.

40. The electronic communication method of claim 38, wherein the fourth message does not verify receipt of the first message by the first party.

41. The electronic communication method of claim 38, wherein the fourth message does not verify receipt of the first message by the first party because it does not include a valid signature by the second party of information representative of the first message.

42. The electronic communication method of claim 38, further comprising receiving, by the first party after sending the fourth message and before receiving the trusted third message, a fifth message from the second party, where the fifth message does not satisfy a predetermined criterion.

43. The electronic communication method of claim 42, wherein the predetermined criterion is that the fifth message does not include the contents of the first message unintelligible to the second party.

44. The electronic communication method of claim 42, wherein the predetermined criterion is that the fifth message does not include a valid signature of the contents of the first message unintelligible to the second party.

45. An electronic communication method comprising:

receiving by a trusted first party a first message from a second party verifying that the second party received a second message from a third party without intervention of the trusted first party, the second message including a portion unintelligible to the second party;

sending by the trusted first party a trusted third message to the third party, the trusted third message verifying that the second party received the second message from the third party; and

sending by the trusted first party a trusted fourth message to the second party, the trusted fourth message enabling intelligible disclosure to the second party of the portion of the second message unintelligible to the second party;

wherein the portion is able to be rendered intelligible to the second party through assistance of the third party.

46. The electronic communication method of claim 45, wherein at least a portion of the first message is unintelligible to the trusted first party.

47. The electronic communication method of claim 45, wherein the first message is based on information not known to the trusted first party.

48. The electronic communication method of claim 45, wherein the first message includes a digital signature of the third party.

49. The electronic communication method of claim 48, wherein the digital signature of the third party signs at least a portion of a message from the second party to the third party.

50. The electronic communication method of claim 45, wherein at least a portion of the trusted third message is unpredictable to the trusted first party.

51. The electronic communication method of claim 45, wherein the trusted third message is based on information not known by the trusted first party.

52. The electronic communication method of claim 45, wherein at least a portion of the trusted fourth message is unintelligible to the trusted first party.

53. The electronic communication method of claim 45, wherein at least a portion of the trusted fourth message is based on information not known to the trusted first party.

54. A method of processing an electronic message comprising:

processing an original message with a first key to produce a first processed message readable only by a party having a second key;

customizing the first processed message to indicate the party having the second key as a recipient thereof, thereby producing a customized first processed message; and

encrypting the customized first processed message with a third key to produce a second processed message readable only by a party having a fourth key.

55. The method of claim 54, wherein the first and second keys are different from one another.

56. The method of claim 54, wherein the third and fourth keys are different from one another.

57. The method of claim 54, wherein customizing comprises customizing the first processed message to indicate a party producing the first processed message as a sender thereof.

58. The method of claim 54, wherein the party having the fourth key is a trusted party.

59. The method of claim 54, further comprising processing the second encrypted message with a fifth key to produce a third processed message.

60. The method of claim 59, wherein the party having the fifth key is the party having the second key.

61. The method of claim 60, wherein the second key and the fifth key are identical.

62. The method of claim 59, where the third processed message uniquely identifies a party which produces it.

63. The method of claim 62, wherein the party which generates the third processed message is the party having the second key.

64. The method of claim 59, further comprising processing the third processed message with the sixth key to produce the second processed message.

65. The method of claim 64, wherein the third processed message is processed by a trusted party.

66. The method of claim 64, further comprising processing the second processed message, produced by processing the third processed message, with the fourth key to produce the first processed message.

67. The method of claim 66, wherein the second processed message, produced by processing the third processed message, is processed by a trusted party.

68. The method of claim 59, wherein message processed using the first key are readable using the fifth key.

69. A method of processing an electronic message comprising:

processing a first processed message, readable only by a party having a first key, with a second key to produce a second processed message uniquely identifying the party processing the first processed message;

wherein the first processed message is a representation of an original message processed with a third key to obtain a third message, readable only to a party having a fourth key, which is further processed with a fifth key to obtain the first processed message.

70. The method of claim 69, wherein the party processing the first processed message is the party having the fourth key.

71. The method of claim 70, wherein messages processed using the second key are readable by processing them with the third key.

72. The method of claim 69, wherein the party having the first key is a trusted party.

73. The method of claim 69, further comprising processing the second processed message using a sixth key to obtain the first processed message.

74. The method of claim 73, wherein the second processed message is processed by a trusted party.

75. The method of claim 73, wherein messages processed using the second key are readable using the sixth key.