Anonymous peer-to-peer communication

• US 20070113274A1
• Filed: 11/14/2006
• Published: 05/17/2007
• Est. Priority Date: 10/04/2002
• Status: Active Grant

• Current Assignee: Rajaraman Hariharan, Ramakrishnan Kannan
• Original Assignee: Rajaraman Hariharan, Ramakrishnan Kannan
• Inventors: Kannan, Ramakrishnan, Hariharan, Rajaraman
• Granted Patent: US 7,877,597 B2
• Time in Patent Office: Days
• US Class Current: 726/13
• CPC Class Codes: H04L 2209/42 Anonymization, e.g. involving pseudonyms
• CPC Class Codes: H04L 63/0414 during transmission, i.e. party's identity is protected against eavesdropping, e.g. by using temporary identifiers, but is known to the other party or parties involved in the communication
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/3271 using challenge-response

Abstract

An anonymous peer-to-peer network has a security protocol that allows hosts in the network to determine whether data received from the network is valid. The requesting host can explicitly determine the data transfer route in packet header information. Each host address on route is encrypted with a public key of a directly preceding host. Consequently, the requesting host can exclude from the data transfer route any host through which the requesting host does not wish to route data. Error detecting codes are used to validate the transmitted data.

Claims

1. A method of transmitting packets, the method comprising the steps of:

a) receiving a packet transmitted between a requesting host and a responding host in a network, wherein the transmitting includes transmitting via a sequence of intermediate hosts between the requesting and responding hosts, whereby intermediate hosts have respective immediately preceding and succeeding hosts in the sequence, wherein a header of the packet contains encrypted addresses for the respective hosts in the sequence, the address for each host being encrypted by a public key of an immediately preceding host in the sequence;

b) decrypting, by the host receiving the packet in step a), the address in the packet header for a succeeding host in the sequence, wherein the decrypting uses a private key of the receiving host, and

c) forwarding the received packet to the succeeding host in the sequence at the decrypted address.

2. The method as claimed in claim 1, wherein the packet received in step a) includes a validation flag encrypted with a public key of the responding host and an offset value, and wherein if the host receiving the packet in step a) is the responding host, the method includes the steps of:

decrypting the validation flag with the receiving hosts private key;

inserting in a response packet a value determined by the decrypting of the validation flag at a certain location in the response packet, the certain location being determined responsive to the offset value; and

forwarding the response packet.

3. The method as claimed in claim 1, wherein the packet received in step a) contains padding data between the packet header and packet data.

4. The method as claimed in claim 3, wherein the padding data is random in length and an encrypted value of this length is contained in the packet header.

5. The method as claimed in claim 1, wherein the addresses are decomposed into discrete values (x₁, x₂, . . . x_n) prior to encryption, such that each address is represented as a function of these discrete values (f(x₁, x₂, . . . x_n)).

6. The method as claimed in claim 1, wherein the sequence of intermediate hosts avoids a particular host.

23. The method as claimed in claim 1, comprising the step of:

registering by the host receiving the packet in step a), wherein the registering includes the step of;

sending a public key to a device accessible by the requesting host.

7-22. -22. (canceled)

24. A computer program product for transmitting packets, the computer program product having instructions for a computer stored on a tangible, computer readable medium, wherein executing the instructions by the computer causes the computer to implement a method comprising the steps of:

a) receiving a packet transmitted between a requesting host and a responding host in a network, wherein the transmitting includes transmitting via a sequence of intermediate hosts between the requesting and responding hosts, whereby intermediate hosts have respective immediately preceding and succeeding hosts in the sequence, wherein a header of the packet contains encrypted addresses for the respective hosts in the sequence, the address for each host being encrypted by a public key of an immediately preceding host in the sequence;

b) decrypting, by the host receiving the packet in step a), the address in the packet header for a succeeding host in the sequence, wherein the decrypting uses a private key of the receiving host; and

c) forwarding the received packet to the succeeding host in the sequence at the decrypted address.

25. The computer program product of claim 24, wherein the packet received in step a) includes a validation flag encrypted with a public key of the responding host and an offset value, and the computer program product includes instructions such that if the host receiving the packet in step a) is the responding host, the executing by the computer causes the computer to implement a method comprising the steps of:

decrypting the validation flag with the receiving hosts private key;

inserting in a response packet a value determined by the decrypting of the validation flag at a certain location in the response packet, the certain location being determined responsive to the offset value; and

forwarding the response packet.

26. The computer program product of claim 24, wherein the incoming packet received in step a) contains padding data between the packet header and packet data.

27. The computer program product of claim 26, wherein the padding data is random in length and an encrypted value of this length is contained in the packet header.

28. The computer program product of claim 24, wherein the addresses are decomposed into discrete values (x₁, x₂, . . . x_n) prior to encryption, such that each address is represented as a function of these discrete values (f(x₁, x₂, . . . x_n)).

29. The computer program product of claim 24 including instructions such that the executing by the computer causes the computer to implement a method comprising the step of:

registering by the host receiving the packet in step a), wherein the registering includes the step of;

sending a public key to a device accessible by the requesting host.

30. A computer system comprising:

a processor; and

a storage device connected to the processor, wherein the storage device has stored thereon a packet transmitting program for controlling the processor, and wherein the processor is operative with the program to execute the program for performing the steps of;

a) receiving a packet transmitted between a requesting host and a responding host in a network, wherein the transmitting includes transmitting via a sequence of intermediate hosts between the requesting and responding hosts, whereby intermediate hosts have respective immediately preceding and succeeding hosts in the sequence, wherein a header of the packet contains encrypted addresses for the respective hosts in the sequence, the address for each host being encrypted by a public key of an immediately preceding host in the sequence;

b) decrypting, by the host receiving the packet in step a), the address in the packet header for a succeeding host in the sequence, wherein the decrypting uses a private key of the receiving host; and

c) forwarding the received packet to the succeeding host in the sequence at the decrypted address.

31. The computer system of claim 30, wherein the packet received in step a) includes a validation flag encrypted with a public key of the responding host and an offset value, and wherein the processor is operative with the program, if the host receiving the packet in step a) is the responding host, to execute the program for performing the steps of:

decrypting the validation flag with the receiving hosts private key;

inserting in a response packet a value determined by the decrypting of the validation flag at a certain location in the response packet, the certain location being determined responsive to the offset value; and

forwarding the response packet.

32. The computer system of claim 30, wherein the incoming packet received in step a) contains padding data between the packet header and packet data.

33. The computer system of claim 32, wherein the padding data is random in length and an encrypted value of this length is contained in the packet header.

34. The computer system of claim 30, wherein the addresses are decomposed into discrete values (x₁, x₂, . . . x_n) prior to encryption, such that each address is represented as a function of these discrete values (f(x₁, x₂, . . . x_n)).

35. The computer system of claim 30, wherein the processor is operative with the program to execute the program for performing the step of:

registering by the host receiving the packet in step a), wherein the registering includes the step of;

sending a public key to a device accessible by the requesting host.