Method of secure anonymous query by electronic messages transported via a public network and method of response

• US 6,023,510 A
• Filed: 12/24/1997
• Issued: 02/08/2000
• Est. Priority Date: 12/24/1997
• Status: Expired due to Fees

• Current Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Original Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Inventors: Epstein, Michael A.
• Primary Examiner(s): Swann, Tod R.
• Assistant Examiner(s): JACK, TODD M
• Application Number:
  US08/998,046
• Time in Patent Office: 776 Days
• Field of Search: 380/25, 380/49, 395/200.59
• US Class Current: 705/74
• CPC Class Codes: G06Q 20/383 Anonymous user system
• CPC Class Codes: H04L 51/00 User-to-user messaging in packet-switching networks, transmitted according to store-and-forward or real-time protocols, e.g. e-mail
• CPC Class Codes: H04L 63/0421 Anonymous communication, i.e. the party's identifiers are hidden from the other party or parties, e.g. using an anonymizer
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30

Abstract

A method for secure anonymous querying by a user of an information provider by electronic mail and for obtaining a reply uses a public key of the provider to form an electronic encrypted query package containing information including a query, a generated random number sequence, a hash of the query, a generated public key of the user, and an identification of a public bulletin board. The query package is preferably sent to the provider via a network from a public terminal. At the information provider the query package is received and decrypted. If the result of hashing the decrypted query is equal to the decrypted hash, a response R is formulated. A response package is formed therefrom by using a generated symmetric key of the information provider and the public key of the user. The response package is posted to the public bulletin board along with the random number sequence. The public bulletin board is accessed by the user in an anonymous manner and the response package, which is identified by the random number sequence, is downloaded and decrypted to obtain response R.

Claims

1. A method for secure anonymous querying by a user of a provider to whom a public key, private key pair is assigned, the public key of the of the provider being publicly obtainable by the user, the method comprising:

formulating by the user of a query to be sent to the provider,

generating by the user of a random number sequence, a public key of the user, and a corresponding private key of the user for sole use with said formulated query;

forming an electronic encrypted query package by the user by operations including encryption with the public key of the provider obtained by the user, said electronic encrypted query package containing information including the formulated query, the generated random number sequence, the generated public key of the user, and an identification of a public bulletin board for posting a message comprising the random number sequence in association with an encrypted response to the query, and said query package being structured such that the contained information can be obtained by the provider by operations including a decryption with the private key of the provider; and

sending by the user of the query package to the provider via a network in a manner that the user is not identifiable to the provider, wherein the generated private key and the generated random number sequence are retained by the user.

2. The method as claimed in claim 1, wherein the query package is sent by the user to the provider from a public terminal.

3. The method as claimed in claim 1, further comprising generating a hash of the query by the user, and wherein said electronic encrypted query package contains information further including the generated hash of the query.

4. The method as claimed in claim 1, further comprising generating a symmetric key by the user, and wherein forming said electronic encrypted query package further comprises encrypting a first part including at least the query using the generated symmetric key of the user and encrypting a second part including at least the generated symmetric key of the user using the public key of the provider.

5. The method as claimed in claim 3, further comprising generating a symmetric key by the user, and wherein forming said electronic encrypted query package further comprises encrypting a first part including at least the query using the generated symmetric key of the user and encrypting a second part including at least the generated symmetric key of the user using the public key of the provider.

15. The method of claim 1 further comprising

accessing the identified bulletin board by the user in order to download the response package associated with that message posted by the provider including the random number sequence generated by the user, and

obtaining by the user by operations including decryption with the private key of the user of the response information in said response package.

16. The method of claim 1 further comprising

receiving by the provider via a network said query package sent by the user,

obtaining by the provider by operations including decryption with the private key of the provider the information in said query package,

formulating by the provider of a response to the query,

forming an electronic encrypted response package by the provider by operations include encryption with the public key of the user contained in said query package, said electronic encrypted response package containing the formulated response to the query, said response package being structured such that the response to the query can be obtained by the user by operations including a decryption with the private key of the user,

posting by the provider of a message comprising the random number sequence in association with the response package to the identified public bulletin board,

accessing the identified bulletin board by the user in order to download the response package associated with that message posted by the provider including the random number sequence generated by the user, and

obtaining by the user by operations including decryption with the private key of the user of the response information in said response package.

6. A method for secure response by a provider, to whom a private key, public key pair is assigned, to an anonymous query from a user comprising:

receiving by the provider via a network an anonymous electronic encrypted query package containing information including a query, a random number sequence generated by the user for sole use in the query package, a public key of the user generated by the user for sole use in the query package, and an identification of a public bulletin board for posting a message comprising the random number sequence in association with an encrypted response to the query, and said query package being structured such that the contained information can be obtained by the provider by operations including a decryption with the private key of the provider;

obtaining by the provider by operations including decryption with the private key of the provider the information in said query package;

formulating by the provider of a response to the query,

forming an electronic encrypted response package by the provider by operations including encryption with the public key of the user contained in said query package, said electronic encrypted response package containing the formulated response to the query, said response package being structured such that the response to the query can be obtained by the user by operations including a decryption with the private key of the user; and

posting by the provider of a message comprising the random number sequence in association with the response package to the identified public bulletin board.

7. The method as claimed in claim 6, wherein a hash of the query is included by the user in the information contained in the query package, and the method further comprises

computing by the provider of a hash of the query, and

comparing by the provider of the computed hash with the hash included in the information contained in the query package.

8. The method as claimed in claim 6, wherein the query package is constructed by the user in a manner such that a first part including at least the query is encrypted using a symmetric key of the user and a second part including at least the symmetric key of the user is encrypted using the public key of the provider, and the method further comprises

decrypting by the provider of the second part of the query package using the private key of the provider to obtain at least the symmetric key of the user, and

decrypting by the provider of the first part of the query package using the symmetric key of the user to obtain at least the query.

9. The method as claimed in claim 7, wherein the query package is constructed by the user in a manner such that a first part including at least the query is encrypted using a symmetric key of the user and a second part including at least the symmetric key of the user is encrypted using the public key of the provider, and the method further comprises

decrypting by the provider of the second part of the query package using the private key of the provider to obtain at least the symmetric key of the user, and

decrypting by the provider of the first part of the query package using the symmetric key of the user to obtain at least the query.

10. The method as claimed in claim 6, further comprising generating a symmetric key by the provider, and wherein forming the electronic encrypted response package further comprises encrypting a first part including at least the response using the symmetric key of the provider and encrypting a second part including at least the symmetric key of the provider using the public key of the user.

11. The method as claimed in claim 7, further comprising generating a symmetric key by the provider, and wherein forming the electronic encrypted response package further comprises encrypting a first part including at least the response using the symmetric key of the provider and encrypting a second part including at least the symmetric key of the provider using the public key of the user.

12. The method as claimed in claim 8, further comprising generating a symmetric key by the provider, and wherein forming the electronic encrypted response package further comprises encrypting a first part including at least the response using the symmetric key of the provider and encrypting a second part including at least the symmetric key of the provider using the public key of the user.

13. A stored message on a public bulletin board responsive to an anonymous query to a provider by a user, said message comprising

a random number sequence provided by the user in the anonymous query for sole use in the anonymous query, and

an associated encrypted electronic response package containing a response to the anonymous query, said response package being structured such that the response to the query can be obtained by the user by operations including a decryption with a private key of the user, the corresponding public of the user having been provided by the user in the anonymous query for sole use in the anonymous query.

14. The stored message as claimed in claim 13, wherein the response package is constructed in a manner that a first part including at least the response is encrypted using a symmetric key of the provider and a second part including at least the symmetric key of the provider is encrypted using a public key of a user who made the anonymous query.