Simultaneous electronic transactions with visible trusted parties

• US 5,629,982 A
• Filed: 08/20/1996
• Issued: 05/13/1997
• Est. Priority Date: 03/21/1995
• Status: Expired due to Term

• Current Assignee: DocuSign Incorporated
• Original Assignee: Silvio Micali
• Inventors: Micali, Silvio
• Primary Examiner(s): CANGIALOSI, SALVATORE A
• Application Number:
  US08/700,270
• Time in Patent Office: 266 Days
• Field of Search: 380/30
• 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 20/3825 Use of electronic signatures
• CPC Class Codes: G06Q 20/388 using mutual authentication without cards, e.g. challenge-response
• CPC Class Codes: G06Q 20/389 Keeping log of transactions for guaranteeing non-repudiation of a transaction
• CPC Class Codes: G06Q 20/401 Transaction verification
• CPC Class Codes: G06Q 20/40975 using encryption therefor
• CPC Class Codes: G06Q 50/188 Electronic negotiation
• 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 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 2463/102 applying security measure for e-commerce
• CPC Class Codes: H04L 51/23 Reliability checks, e.g. acknowledgments or fault reporting
• 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 9/0841 involving Diffie-Hellman or related key agreement protocols
• CPC Class Codes: H04L 9/085 : Secret sharing or secret splitting, e.g. threshold schemes
• CPC Class Codes: H04L 9/321 : involving a third party or a trusted authority
• CPC Class Codes: H04L 9/3247 : involving digital signatures

Abstract

A number of electronic communications methods are described involving a first and a second party (i.e., sender and recipient), with assistance from at least a trusted party, enabling electronic transactions in which the first party has a message for the second party. The first party, the second party and the trusted party undertake an exchange of transmissions, such that if all transmissions reach their destinations the second party only receives the message if the first party receives at least one receipt. Preferably, the identity of the first party is temporarily withheld from the second party during the transaction. At least one receipt received to the first party enables the first party to prove the content of the message received by the second party.

Claims

1. A method of transmitting a message using a trusted party, comprising the steps of:

(a) a sender causing the trusted party to be provided with a version of the message that is encrypted in a key that is not available to the trusted party, and causing the trusted party to receive information identifying the sender and information identifying a recipient;

(b) the trusted party using the information identifying the recipient to cause information to be provided to the recipient that allows the recipient to retrieve the message and identify the sender; and

(c) the trusted party causing a receipt for the message to be provided to the sender.

2. A method according to claim 1, wherein the message is intelligible to the recipient.

3. A method according to claim 1, wherein the trusted party is implemented using a tamper-proof device.

4. A method according to claim 2, wherein the message is encrypted with a key of the recipient.

5. A method according to claim 1, wherein the sender provides a proof that the sender causes the message to be provided to the recipient.

6. A method according to claim 5, wherein the proof includes a digital signature.

7. A method according to claim 5, wherein the proof is provided to the trusted party.

8. A method according to claim 7, wherein the trusted party provides a proof to the recipient.

9. A method, according to claim 1, wherein the receipt is provided by the recipient.

10. A method, according to claim 9, wherein the receipt proves the contents of the message.

11. A method, according to claims 10, wherein the receipt contains a digital signature of the recipient.

12. A method, according to claim 1 wherein the receipt proves the contents of the message.

13. A method of transmitting a message using a trusted party, comprising the steps of:

(a) a sender causing the trusted party to be provided with an encrypted version of the message, information identifying the sender, and information identifying a recipient;

(b) the trusted party using the information identifying the recipient to cause information to be provided to the recipient that allows the recipient to retrieve the message and identify the sender even if the recipient does not receive the message, or any version thereof, directly from the sender; and

(c) the trusted party causing a receipt for the message to be provided to the sender.

14. A method according to claim 13, wherein the encrypted version of the message is unintelligible to the trusted party.

15. A method according to claim 13, wherein the trusted party is implemented using a tamper-proof device.

16. A method according to claim 13, wherein the message is encrypted with a key of the recipient.

17. A method according to claim 13, wherein the sender provides a proof that the sender caused the message to be provided to the recipient.

18. A method according to claim 17, wherein the proof includes a digital signature.

19. A method according to claim 17, wherein the receipt is provided to the trusted party by the recipient.

20. A method, according to claim 19, wherein the receipt proves the contents of the message.

21. A method, according to claim 20, wherein the receipt contains a digital signature of the recipient.

22. A method of transmitting a message using a trusted party, comprising the steps of:

(a) a sender causing the trusted party to be provided with a first encrypted version of the message;

(b) the trusted party causing a second encrypted version of the message to be provided to the recipient, wherein the second encrypted version of the message commits the contents of the message but is unintelligible to the recipient; and

(c) in response to the recipient providing an acknowledgement for receiving the second encrypted version of the message, the trusted party causing information to be provided to the recipient that allows the recipient to retrieve the message and identify the sender and the trusted party causing the sender to receive a receipt for the message.

23. A method according to claim 22, wherein the first encrypted version of the message is unintelligible to the trusted party.

24. A method according to claim 22, wherein the second encrypted version of the message does not reveal the identity of the sender to the recipient.

25. A method according to claim 22, wherein the receipt includes the acknowledgement.

26. A method according to claim 22, wherein the receipt indicates that the recipient has been provided with the message.

27. A method according to claim 22, wherein the receipt proves the contents of the message.

28. A method according to claim 22, further comprising the step of:

(d) in response to the trusted party not receiving the acknowledgement, having the trusted party cause the message to be provided to the recipient by alternative means.

29. A method according to claim 28, wherein the alternative means produces an alternative receipt for delivery of the message.

30. A method according to claim 22, wherein the acknowledgement commits the contents of the message.

31. A method according to claim 22, further comprising the steps of:

(d) the trusted party requesting from the recipient a proof that the recipient has obtained an intelligible version of the message; and

(e) if the trusted party does not receive the proof, having the trusted party deliver the message by alternative means.

32. A method according to claim 31, wherein the alternative means produces an alternative receipt for delivery of the message.

33. A method according to claim 31, wherein the receipt includes the proof.

35. A method according to claim 22, wherein the first encrypted version of the message is identical to the second encrypted version of the message.

34. A method according to clam 31, wherein the receipt includes the alternative receipt.