http://www.wired.com/news/politics/0,1283,46126,00.html Pentagon Hides Behind Onion Wraps By Declan McCullagh (declanat_private) 2:00 a.m. Aug. 17, 2001 PDT Onions may be the secret ingredient in protecting the Pentagon's classified information. During an afternoon presentation at the Usenix Security conference on Thursday, a researcher at the U.S. Naval Research Laboratory described a technology known as "Onion Routing," which preserves anonymity by wrapping the identity of users in onion-like layers. "Public networks are vulnerable to traffic analysis. Packet headers identify recipients, and packet routes can be tracked," said Paul Syverson, who works at the NRL's Center for High Assurance Computer Systems. "Even encrypted data exposes the identity of the communicating parties." [...] Syverson said that the U.S. government was awarded patent number 6,266,704 for Onion Routing on July 24. That announcement prompted an angry reaction from Usenix attendees, many of whom are programmers, security consultants and system administrators, who aren't big fans of software patents -- especially in the area of anonymous communications, where there's been so much prior work before the Navy ever got involved. Mathematician David Chaum, for instance, wrote an article titled "Untraceable Electronic Mail, Return Addresses and Digital Pseudonyms" for Communications of the ACM as far back as 1981. Lance Cottrell, who now runs anonymizer.com, wrote part of the mixmaster system in the early 1990s, and similar techniques were discussed on the cypherpunks mailing list even earlier. Syverson, who is listed on the patent with co-inventors Michael Reed and David Goldschlag, defended the government's move. "It is a necessary step for those of us working for the government to bring technology to the public," Syverson said. The patent describes Onion Routing, which has been the subject of analysis at previous security conferences, as providing "an electronic communication path between an initiator and a responder on a packet-switching network comprising an onion routing network that safeguards against traffic analysis and eavesdropping by other users of the packet switching network" such as the Internet. [...] ********* http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1='6,266,704'.WKU.&OS=PN/6,266,704&RS=PN/6,266,704 United States Patent 6,266,704 Reed , et al. July 24, 2001 _________________________________________________________________ Onion routing network for securely moving data through communication networks Abstract The onion routing network is used to protect Internet initiators and responders against both eavesdropping and traffic analysis from other users of the Internet. In the onion routing of the invention, instead of making connections directly to a responding machine, users make connections through onion routers. The onion routing network allows the connection between the initiator and responder to remain anonymous. Anonymous connections hide who is connected to whom and for what purpose from outside eavesdroppers. _________________________________________________________________ Inventors: Reed; Michael G. (Bethesda, MD); Syverson; Paul F. (Silver Spring, MD); Goldschlag; David M. (Silver Spring, MD) Assignee: The United States of America as represented by the Secretary of the Navy (Washington, DC) Appl. No.: 086541 Filed: May 29, 1998 [...] _________________________________________________________________ Description _________________________________________________________________ BACKGROUND OF THE INVENTION 1.0 Field of the Invention The present invention relates to the field of moving user real-time data within a communication network and, more particularly, to a system which moves data within a communication network, such as the Internet, without revealing the identity of the initiator of the data, nor the identity of the receiver of the data, nor the content of the data. 2.0 Description of the Prior Art The present invention is concerned with the right to privacy involved in electronic communication which may be better described by first discussing other forms of more commonly known communications. For example, letters sent through the Post Office are usually in an envelope marked with the sender's and recipient's addresses. The general public trusts that the Post Office does not peek inside the envelope, because the contents are private. The general public also trusts that the Post Office does not monitor who sends mail to whom, because that information is also considered private. These two types of sensitive information, the contents of an envelope and its addresses, apply equally well to electronic communication over the Internet. As the Internet becomes an increasing important part of modern day communication and electronic commerce, protecting the privacy of electronic messages also becomes increasingly important. Just like mail, electronic messages travel in envelopes, that is, electronic envelopes. Protecting the privacy of electronic messages requires both safeguarding the contents of their envelopes and hiding the addresses on their envelopes. Although communicating parties usually identify themselves to one another, there is no reason that the use of a public network, such as the Internet, ought to reveal to others who is talking to whom and what they are talking about. The first concern is traffic analysis, the latter is eavesdropping. By making both eavesdropping and traffic analysis hard, the privacy of communication is protected. However, anonymity need not be completely maintained because two parties communicating with each other may need to identify each other. For example, if a Web surfer wants to buy something using the electronic equivalent of cash, the purchaser may need to be identified to properly establish the debt being incurred; however, the network need not know any of this information. If an electronic envelope keeps its contents private, and the address on the envelope is also hidden, then any identifying information can only be inside the envelope. So for anonymous communication, we also should remove identifying information from the contents of an envelope. This may be called anonymizing a private envelope. An anonymous connection is a communications channel for which it is infeasible to determine both endpoints, that is, which principal initiated the communication and whom receives the communication. The principal initiating the connection is the initiator, and the principal to whom the initiator connects is the responder. The present invention implements a mechanism for anonymous connections that operates below the application layer and supports a variety of Internet applications, wherein the application layer is the highest layer within the hierarchy of the protocols being used to perform the data transfer. The usage of anonymous communication is known and generally referred to by the use of various terms in the art. For example, anonymous "Mixes" were introduced in 1985 as a store and forward mechanism for anonymously moving data through a network. These Mixes are not suitable for bidirectional real-time communication which is of importance to the present invention. Anonymous remailers, also known in the art, have been used to store and forward mail from a sender to a recipient without revealing the identity of the sender to observers of the network. Different versions of these remailers use Mixes in a highly application specific way which limits their applicability for other uses. Anonymous bidirectional real-time communication for Integrated Service Digital Network (ISDN) has also been explored, especially as in related phone switching means. Mixes are incorporated into an ISDN phone switch to permit anonymous connections between callers within the same ISDN switch. The usage of these anonymous connection means is dependent upon the characteristics of the ISDN phone switches which, in turn, has inherent limitations which, in turn, limit their usage. The first mention of near real-time Mixes for the Internet appears in the Pipe-Net techniques also known in the art. Pipe-Net's design provides fixed bandwidth, low-capacity communications channels strongly protected against both active and passive traffic analysis attacks. However, the fixed bandwidth and low-capacity communication limit their usage. Further, to our knowledge this Pipe-Net's design has never been built, fully described, nor formally published. The anonymizer, known in the art, provides weak protection against traffic analysis of World Wide Web (WEB) communications, by providing a centralized service that removes identifying information from the data stream. So called "Crowds" extends this approach to decentralize the proxy. However, the Anonymizer does not protect against passive attacks at the centralized proxy; whereas Crowds does not protect against global passive attacks. It is desired to provide a general purpose system that allows anonymous connections to move data through a communication network and that does not suffer the drawbacks of the prior art. OBJECTS OF THE INVENTION It is a primary object of the present invention to provide a system for electronic communications that protect the identity of the initiator and the intended receiver of the data, as well as the content of the data, from traffic analysis and eavesdropping. The system has variable bandwidth, high capacity, near real-time, bidirectional, and application independent communication characteristics. It is another object of the present invention to provide a subcomponent for the system that separates anonymity of the connection from anonymity of the data passing over the connection. It is still another object of the present invention to provide a distributed routing network, comprised of systems of the present invention, that can be configured in many ways to shift trust between network elements, thereby shifting the responsibility for the protection of private information to the cognizant parties. For example, a large company may install a system of the present invention on the firewall separating its protected site from the open Internet and, therefore, take the responsibility to protect its own information. This system, once instituted, would be integrated into the distribution routing network. Further still, it is an object of the present invention to provide a system that operates below the application layer. The system of the present invention supports many unmodified applications by means of proxies. The system of the present invention includes proxies that may be used for Web browsing, remote login, electronic mail and raw data connections. SUMMARY OF THE INVENTION The present invention is directed to a method for establishing and utilizing a virtual circuit for moving data for electronic communication within a communication network that provides application independent, real-time, and bi-directional anonymous connections throughout the communication network that are resistant to both eavesdropping and traffic analysis. The present invention provides a virtual circuit that is a pathway between two devices, one defined as an initiator and the other defined as a responder, communicating with each other in a packet switching system, such as the Internet. The virtual circuit comprising a plurality of onion routers arranged adjacent to each other and where adjacent onion routers maintain longstanding connections to each other and where each onion router has a protocol to provide communications therebetween. Each of the onion routers is responsive to an onion, having a layered data structure, with one layer per each of the onion routers in the pathway. Each layer of the onion comprises an encryption of the identity of the next onion router in the pathway and encryption material. In operation, the initiator makes a request to a proxy to establish the virtual circuit through the onion routers. In one embodiment, the proxy connects to a second proxy which then defines the pathway, and in another embodiment, the first proxy defines the pathway itself with the pathway consisting of individual paths between adjacent onion routers. [...] ------------------------------------------------------------------------- POLITECH -- Declan McCullagh's politics and technology mailing list You may redistribute this message freely if you include this notice. 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