Agile network protocol for secure communications with assured system availability

• US 7,996,539 B2
• Filed: 12/13/2005
• Issued: 08/09/2011
• Est. Priority Date: 10/30/1998
• Status: Expired due to Fees

• Current Assignee: VirnetX Inc. (Virnetx Holding Corporation)
• Original Assignee: VirnetX Inc. (Virnetx Holding Corporation)
• Inventors: Munger, Edmund Colby, Sabio, Vincent J., Short, III, Robert Dunham, Gligor, Virgil D., Schmidt, Douglas Charles
• Primary Examiner(s): Etienne, Ario
• Assistant Examiner(s): Kim, Hee Soo
• Application Number:
  US11/301,022
• Publication Number:
  US 20060123134A1
• Time in Patent Office: 2,065 Days
• Field of Search: 709/226, 709/227
• US Class Current: 709/227
• CPC Class Codes: H04L 2101/604 Address structures or formats
• CPC Class Codes: H04L 45/20 Hop count for routing purposes, e.g. TTL
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 61/2539 Hiding addresses; Keeping addresses anonymous
• CPC Class Codes: H04L 61/30 Managing network names, e.g. use of aliases or nicknames name-to-address mapping H04L61/45
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS
• CPC Class Codes: H04L 61/5092 by self-assignment, e.g. picking addresses at random and testing if they are already in use
• CPC Class Codes: H04L 63/0272 Virtual private networks
• CPC Class Codes: H04L 63/04 for providing a confidential data exchange among entities communicating through data packet networks
• CPC Class Codes: H04L 63/0407 wherein the identity of one or more communicating identities is hidden cryptographic mechanisms or cryptographic arrangements for anonymous credentials or for identity based cryptographic systems H04L9/00
• 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 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• 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 63/1441 Countermeasures against malicious traffic countermeasures against attacks on cryptographic mechanisms H04L9/002
• CPC Class Codes: H04L 63/1491 using deception as countermeasure, e.g. honeypots, honeynets, decoys or entrapment
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 9/065 Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
• CPC Class Codes: H04M 3/42008 Systems for anonymous communication between parties, e.g. by use of disposal contact identifiers

Abstract

A plurality of computer nodes communicates using seemingly random IP source and destination addresses and (optionally) a seemingly random discriminator field. Data packets matching criteria defined by a moving window of valid addresses are accepted for further processing, while those that do not meet the criteria are rejected. In addition to “hopping” of IP addresses and discriminator fields, hardware addresses such as Media Access Control addresses can be hopped. The hopped addresses are generated by random number generators having non-repeating sequence lengths that are easily determined a-priori, which can quickly jump ahead in sequence by an arbitrary number of random steps and which have the property that future random numbers are difficult to guess without knowing the random number generator'"'"'s parameters. Synchronization techniques can be used to re-establish synchronization between sending and receiving nodes.

Claims

1. A method of anonymously communicating data between a first node and a second node coupled via a network, comprising the steps of:

at the first node,

(a) using a first algorithm to select from among a first plurality of different network addresses each of which is mapped in the network to the first node, and using each selected network address in a header of a packet that is transmitted from the first node over the network to the second node;

(b) evaluating the headers of received packets received at the first node to determine whether each header contains a network address that conforms to a second algorithm used by the second node to select from among a second plurality of different network addresses each of which is mapped in the network to the second node,

(c) upon determining that the header of a received packet received at the first node contains a network address that conforms to the second algorithm, accepting the received packet for processing; and

upon determining that the header does not contain a network address that conforms to the second algorithm, rejecting the received packet for further processing; and

(d) wherein each selected network address is selected by hopping among the first plurality and second plurality of different network addresses so that the network addresses selected in each header of received packet appears random; and

wherein the first and second algorithms select each network address on a quasi-random basis.

2. The method of claim 1, wherein the network comprises an Internet Protocol (IP) network, and wherein each network address comprises an Internet Protocol (IP) source or destination address.

3. The method of claim 2, wherein:

step (1) comprises the step of using each selected IP address as the destination address of the second node; and

step (2) comprises the step of using each selected IP address as the destination address of the first node.

4. The method of claim 2, wherein:

step (1) comprises the step of using each selected IP address as the source address of the first node; and

step (2) comprises the step of using each selected IP address as the source address of the second node.

5. The method of claim 1, wherein the first and second algorithms select a different network address for each outgoing packet.

6. A method of anonymously communicating data between first and second nodes in a network, comprising the steps of:

at the first node,

(1) storing a transmit netblock comprising a plurality of pairs of source and destination IP addresses that will be used for communicating with the second node, and an algorithm for selecting pairs of source and destination IP addresses from among the plurality of pairs of source and destination IP addresses;

(2) generating a plurality of IP packets each comprising one of the selected pairs or source and destination IP addresses;

(3) transmitting each IP packet generated in step (2) to the second node, wherein each pair of source and destination IP addresses of the netblock are selected by hopping among the source and destination IP addresses so that the source and destination network addresses selected for each IP packet appears random; and

wherein upon receipt by the first node of a plurality of IP packets from the second node, for each IP packet received;

(a) determining whether the received IP packet contains a valid source and destination IP address, wherein the validity of each address is determined with reference to a second algorithm;

(b) upon determining that the received IP packet contains a valid source and destination IP address, accepting the IP packet for further processing; and

upon determining that the received IP packet does not contain a valid source and destination IP address, rejecting the IP packet; and

wherein the first and second algorithms select each network address on a quasi-random basis.

7. The method of claim 6, wherein the algorithm selects a different pair of source and destination addresses for each IP packet transmitting in step (3).

8. The method of claim 6, further comprising the step of receiving the transmit netblock and the algorithm from the second node.

9. The method of claim 6, wherein the second algorithm determines whether each address is valid by generating a range of predictions encompassing a plurality of possible transmitted source and destination addresses, and comparing each address to the range of predictions.

10. The method of claim 9, further comprising the step of discarding received IP packets containing an IP address that was previously received.

11. A system comprising:

a first node configured and arranged so that data can be anonymously communicated between the first node and a second node;

wherein the first node is configured and arranged so as to (a) use a first algorithm to select from among a first plurality of different network addresses each of which is mapped in the network to the first node, and (b) use each selected network address in a header of a packet that is transmitted over the network to the second node;

wherein each selected network address is selected by hopping among the first plurality and second plurality of different network addresses so that the source and destination network addresses selected in each header of a packet appear random;

wherein the first node is further configured and arranged so as to evaluate a the headers of received packets received at the first node to determine whether each header contains a network address that conforms to a second algorithm used by the second node; and

upon determining that a header of a received packet contains a network address that conforms to the second algorithm, accept the packet for processing; and

upon determining that the header does not contain a network address that conforms to the second algorithm, reject the packet for processing; and

wherein the first and second algorithms select each network address on a quasi-random basis.

12. The system of claim 11, wherein the network comprises an Internet Protocol (IP) network, and wherein each network address comprises an Internet Protocol (IP) source or destination address.

13. The system of claim 12, wherein the first node is further configured and arranged so as to use each selected IP address as the destination address of the second node;

and the second node is further configured and arranged so as to use each selected IP address as the destination address of the first node.

14. The system of claim 12, wherein the first node is further configured and arranged so as to use each selected IP address as the source address of the first node;

and second node is further configured and arranged so as to use each selected IP address as the source address of the second node.

15. The system of claim 11, wherein the first and second algorithms are configured and arranged so as to select a different network address for each outgoing packet.

16. A system for anonymously communicating data between first and second nodes in a network, comprising:

wherein the first node is configured and arranged so as to (a) store a transmit netblock comprising a plurality of pairs of source and destination IP addresses that will be used for communicating with the second node, (b) perform a first algorithm so as to select pairs of source and destination IP addresses from among the plurality of pairs of source and destination IP addresses;

(c) generate a plurality of IP packets each comprising one of the selected pairs or source and destination IP addresses; and

(d) transmit each IP packet generated in (c) to the second node; and

wherein each pair of source and destination IP addresses of the netblock are selected by hopping among the source and destination IP addresses so that the source and destination network addresses selected for each IP packet appears random,

wherein the first node is further configured and arranged so as to receive a plurality of IP packets at the first node and, for each received IP packet;

(a) determine whether the received IP packet contains a valid source and destination IP address so as to indicate that the received IP packet is from the second node, and

(b) the validity of each address is determined with reference to a second algorithm configured and arranged so as to determine whether the received IP packet contains a valid source and destination IP address so that (i) if valid the IP packet is further processed; and

(ii) if not valid the IP packet is rejected; and

wherein the first and second algorithms select each network address on a quasi-random basis.

17. The system of claim 16, wherein the algorithm selects a different pair of source and destination addresses for each IP packet transmitted in (d).

18. The system of claim 16, wherein the first node is further configured and arranged so as to receive the transmit netblock and the algorithm from the second node.

19. The system of claim 16, wherein the second algorithm is configured and arranged so as to determine whether each address is valid by generating a range of predictions encompassing a plurality of possible transmitted source and destination addresses, and compare each address to the range of predictions.

20. The system of claim 19, wherein the first node is further configured and arranged so as to further discard received IP packets containing an IP address that was previously received.