U.S. government patents "Onion Routing" anon browsing technique

[Declan McCullagh]

http://www.wired.com/news/politics/0,1283,46126,00.html

    Pentagon Hides Behind Onion Wraps
    By Declan McCullagh (declan at wired.com)
    2:00 a.m. Aug. 17, 2001 PDT

    [...]

    [Paul] 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.

    [...]




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