One document matched: draft-irtf-smug-mcast-policy-00.txt


Internet Engineering Task Force        Patrick McDaniel (U.of Michigan)
INTERNET-DRAFT                         Hugh Harney (Sparta)
draft-irtf-smug-mcast-policy-00.txt    Peter Dinsmore (NAI Labs)
May 2000                               Atul Prakash (U.of Michigan)


                     Multicast Security Policy
                 <draft-irtf-smug-mcast-policy-00.txt>


Status of this memo

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Abstract

  Security is increasingly becoming a concern in applications built on
  multi-party communication.  Centrally, protection of the application
  content from non-authorized or malicious parties is the fundamental
  goal of any security policy specification.  This draft seeks to
  illuminate the design space of secure multicast communication
  policy.  The security requirements of existing application policies
  are intended to be addressable by these policy dimensions.  It is
  from an understanding of policy design space that the mechanisms for
  policy specification and enforcement can be derived.

Table of Contents

1. Introduction

  Although security policy is an oft mentioned component of security
  infrastructures, no single definition has been found to address the
  needs of all parties and environments.  One working definition
  defines policy as:

      ``.. the group security relevant behaviors, access control
      parameters, and security mechanisms.'...'' [HCH+00]

  This definition best fits the viewpoint of policy as defining how

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  security defines group behavior, who are the entities allowed to
  participate, and which mechanisms will be used to achieve mission
  critical goals.  For the purposes of this document, we will accept
  these dimensions as defining the relevant properties of secure
  multicast policy.

  A group security context is the set of keys, members, protocols, and
  algorithms used to secure a singular group communication.  A policy
  defines (directly or indirectly) how the security context should be
  derived.  A policy framework defines the entities and protocols used
  to define, interpret, negotiate, and distribute a secure group
  policy.

  Once an understanding of what constitutes a policy is obtained, the
  natural question of policy specification arises.  This question
  speaks to the requirements of both the representation and
  interpretation of policy, and the means by which policy is
  distributed and authenticated.

  The central aims of this document are the definition of a group
  model and an investigation of the dimensions along which policy may
  be defined in secure multiparty communication.  The group model
  should be comprehensive and flexible; the requirements of arbitrary
  group communication security should be expressible and achievable.
  In this model, we attempt to identify those dimensions of policy
  relevant to secure multicast.  This document does not seek to
  identify specific solutions or mechanisms for providing group
  security policy specification and enforcement, leaving this to other
  future documents.

  The remainder of this section describes the major components and
  challenges of secure group policy.  The following two subsection
  describe a major distinction between group and local policy upon
  which the model defined in this document rests.  The issues of
  policy specification and negotiation are briefly described in
  subsequent sections.

  1.1 Group Policy 

  A group policy defines the behavior of the group.  Included in this
  definition is the types of security guarantees provided to the
  participants, the ways in which the guarantees are provided and the
  definition of the relationships between the group participants.

  1.2 Local Policy

  Obtained from the local environment, a local policy defines the
  requirements and credentials of the local entities.  Upon receiving
  the group policy, both the group and local policies should be
  reconciled.  Irreconcilable conflicts (see negotiation below) 
  requires the local host abstain from participation in the group.

  In addition to specifying minimal standards for group behavior, the

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  local policy should identify which identities or credentials should
  be accepted as authoritative.  In the case of identities, an
  authentication method should also be defined.

  1.3 Policy Specification

  Once agreement has been reached on the policy dimensions that will
  be supported by a policy framework the issue of specification
  arises.  A policy specification language defines both how a policy
  is represented and the rules with which the representation is
  interpreted.  The following text outlines several design goals of
  the policy representation.

  The policy language should be unambiguous.  Because a policy will be
  interpreted by host software, the mapping of the policy to mechanism
  and credentials must be deterministic.

  The policy language should be succinct.  The costs associated with
  policy distribution is likely to be a key determinant in the success
  of the policy framework.  As such, the language should be designed
  to be represented in as small a electronic format as possible.

  The policy language should be clear.  A requirement of the SMuG
  architecture is that policy definitions must originate from security
  personnel which may or may not be directly involved in application
  development.  Thus, the ability to relate the representation to real
  world objects is a goal.  Where possible, a policy representation
  should be human readable.

  1.4 Policy Negotiation

  Reconciliation, possibly through participant negotiation, of local
  and group policy is a key task of the SMuG framework.  A open issue
  is the extent to which a group policy may be altered during this
  negotiation.  Secure multicast groups may be large and extend over
  several administrative domains.  Thus, the potentially competing
  requirements of group members must be weighed in creating a single,
  coherent group security policy.

  1.5 Related Documents

  This informational document is intended to motivate the design of
  the Secure Multicast Research Group [SMuG] secure multicast
  architecture [HCBP99,CCP+99].  Specifically, this document intends
  to identify potential policies that may be supported by the SMuG
  secure multicast framework through the policy framework (problem
  area 3).  This should also serve as an informal policy requirements
  specification for the management of keying material (problem area 2)
  and multicast data handling (problem 1) layers of the SMuG
  architecture.  A more detailed document defining the requirements of
  the policy framework is the subject of a future draft.  A taxonomy
  of issues relating to the SMuG framework can be found in [CP99].


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  A secondary goal of this document is a requirements definition for
  the framework policy specification language.  In this, we intend to
  outline a general model which can be used as the basis of policy
  specification.  While the specifics of the policy language are not
  stipulated, we expect that future documents will realize this model
  in defining an electronic policy representation.

  1.6 Document Organization

  The remainder of this document is as follows.  Section 2 defines a
  group model through a specification of the actions and roles of
  group participants.  Section 3 describes the potential dimensions on
  which policy may be defined, and identifies those policies required
  for secure multicast communication.

2. Group Model

  This section outlines the group model under over which we define
  policy, and is much motivated by the emerging GSAKMP protocol
  [HCH+00].  In this model, the defining characteristic of a group is a
  statement of rights associated with roles assumed by group members.

  A role defines the rights and responsibilities of any group member
  assuming that role.  In gaining access to the group, a group member
  must assume one or more roles.  External entities may serve as roles
  within the group.  In this view, the task of the policy framework is
  the specification and distribution of role definition, the means and
  specifics of role access control, and rules guiding the realization
  of these role defined activities in the underlying mechanisms.

  To motivate (one definition) of roles, we present an enumeration of
  activities relating to the management of a group security context.

  ##  Action               Description
  --  -------------------  ------------------------------------------

  1   key creation         right to create a session key, or to
                           generate rekeying material

  2   key dissemination    This right allows a member to distribute
                           keying material.

  3   rekey action         right to initiate a group rekey.
      initiation

  4   key access           right to gain access to the session key

  5   policy creation      right to create/assert a group policy

  6   policy modification  right to modify the group policy

  7   grant rights         right to grant rights to members/entities
                           external to the policy

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  8   authorize member     right to authorize/state authenticity of
                           group member

  9   admit member         right to admit a member to the group

  10  eject member         right to remove a member from the group

  11  audit group          right to monitor access control messages or
                           membership information

  Tables 1 and 2 describe the set of access rights and roles assumed
  by group participants.  This description of roles and rights is
  intended to be informational.  Particular instantiations of the SMuG
  framework may define roles and rights as appropriate for their
  purposes.  We describe the meaning of each role in the following
  subsections.

  ------------------------------------------------------------------

      #            Role                     Access Rights
      -  ----------------------------  ------------------------

      1  group owner                   5, 6, 7, 11
  
      2  group key authority           1, 2, 3, 4, 11
  
      3  group membership authority    8, 9, 10
  
      4  member                        4
    
  Table 1 - Role Access Rights
  ------------------------------------------------------------------

  The following subsections describe the purpose, rights, and
  responsibilities of the group roles defined in Table 1.

  2.2.1  Group Owner

  The group owner is the initiator of the group and controls the
  policy for the group.  The group owner is the entity that states
  rules for admittance and determines the behavior of the group
  (policy).  Also, it must identify the authorities that perform the
  various management duties for the group.  Note that the group owner
  may or may not be a member of the group.

  2.2.2 Group Key Authority

  The group key authority is the controller of keying actions within
  the group.  As such, this entity creates and coordinates the
  distribution of all session keys and related keying material.  The
  entities to which keying material will largely be driven by
  information received from the group membership authority.  Note that

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  the group key authority need not be a member of the group or
  distinct from the group owner.

  2.2.3 Group Membership Authority

  The group membership authority is the controller of membership
  actions within the group.  As such, this entity authorizes and
  admits the members of the group.  The means used to perform these
  actions is dependent on the policy stated by the group owner.  Note
  that the group key authority need not be a member of the group.

  2.2.4 Member

  A group member is a participant in the group.  The right to access
  the session key implies the ability to both send and receive
  messages within the group.  Obviously, the member is required to be
  a member of the group.  Note that a member specifically does not
  have any rights to monitor the group control messages or membership.
  If needed, these rights may later be granted through the definition
  of a new role.

3. Policies

  3.1 Group Policy

  A group policy defines group services and participant roles to be
  implemented by the group.  The central goal of the SMuG policy
  framework (problem area 3) is to provide services for specification,
  distribution, and negotiation of the group policy.

  As defined by roles (see section 2.2 above), specification of the
  group policy is to be performed by some authorized entity.  The
  group policy is to be distributed to joining members by policy
  distribution points (see [CCP+99]).  The mechanism and architecture
  of the specification and distribution mechanism is beyond the scope
  of this document.

  The following subsections define several dimensions along which a
  group policy may be defined.

  3.1.1 Rekeying Policy

  A common strategy to support secure group communication among
  trusted members is to use a common symmetric session key (e.g. GKMP
  [HMR97a,HMR97b], GSAKMP [HCH+00], Antigone [MPH99], DCCM [DBH+00]).
  An important policy issue for a group communication application is
  deciding when a session must be rekeyed, i.e., the old session key
  is discarded and a new session key is sent to all the members.  This
  policy is likely to drive much of the key management activities of
  the key management protocols [HBH00].

  A rekeying policy defines how and when session keys are created and
  (re)distributed.  The management of the session keys is a central

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  determinant of the security afforded by the resulting session.  As
  such, the rekeying policy drives many subsequent policy and
  mechanism related decisions.

  Associated with each rekeying policy is a number of properties which
  define the security guarantees being provided to the group.  Several
  properties of the session keying include:

     session key independence - no meaningful information about one
     session can be derived from another.

     perfect forward secrecy (PFS)- the property that a session key
     provides no meaningful information about future session keys.

     membership forward secrecy (MFS) - the property that a member
     leaving the group cannot obtain meaningful information about
     future group communication.
     
     perfect backward secrecy (PBW) - the property that a session key
     provides no meaningful information about past session keys.

     membership backward secrecy (MFS) - the property that a member
     joining the group cannot obtain meaningful information about past
     group communication.

     failure secrecy - the property that a failed process can not
     continue to actively or passively participate in the group.  The
     means in which failures are detected and reported is beyond the
     scope of this document.

     compromise secrecy - the property that a compromised process can
     not continue to actively or passively participate in the group.
     The means in which compromises are detected and reported is
     beyond the scope of this document.

     limited lifetime - the property that a session key has maximum
     lifetime (which may be measured in time, bytes transmitted, or
     some other globally measurable metric of group communication).

  Similarly, the mechanism used to create session keys may have the
  following properties:

     contributory keying - the property that each group member
     participate in the creation of the session key.

     centralized keying - converse to contributory keying, this
     property requires that (only) one or more trusted parties
     contribute to the creation of the key.

  These properties are realized in some combination of key creation
  algorithm and rekeying protocols.  The definition of these
  algorithms, protocols, and the (policy to mechanism) mapping
  function is beyond the scope of this document.  The Antigone system

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  [MPH99] investigates the means by which policy may be mapped into
  mechanisms.

  Support for some or all of the rekeying policies defined in this
  section is a requirement of the SMuG Policy framework.

  A representation of a rekeying policy may be the set of properties
  which the rekeying mechanism is required to provide.  Each property
  may require additional policy specification and mechanisms.  To
  illustrate this point, we describe the features and requirements of
  two policies mentioned above.

  3.1.1.1 Membership Forward Secrecy

  A membership forward secrecy policy is useful in secure conferencing
  applications.  The content of conferencing application is often
  driven by the members of the group.  (e.g.  The content of a sales
  meeting may need to be protected from suppliers who have exited the
  session.)

  In membership forward secrecy, The group is required to protect
  content from members of past security contexts.  Therefore, any
  rekeying mechanism and protocol supporting an MFS policy must
  provide the following features:

    a) protection of the LEAVE process (reliable, authenticated, and
       timely)
    b) rekey after every group member LEAVE
    c) provide PFS rekeying

  It is immediately obvious MFS may be both be difficult to provide
  and expensive.  Thus, MFS policies may be incompatible with large or
  highly dynamic groups.  Support for MFS in the secure multicast
  framework may not be required.

  3.1.1.2 Limited Lifetime

  Limited lifetime rekeying can be useful in a secure on-line
  subscription service.  Paying members would periodically be sent a
  new key that is valid until the next subscription interval.  The
  GKMP [HMR97a,HMR97b] protocol implements a time-sensitive rekeying
  policy (albeit without the session key independence required by the
  this example).  Limited lifetime rekeying without independence
  provides (primarily) protection against cryptanalysis of the session
  key.  The MARKS system [Bri99] provides an efficient means of
  supporting limited lifetime rekeying within arbitrarily large groups.

  Where limited lifetime rekeying is used, the metric used to measure
  key lifetime and the threshold at which rekeying is required must be
  stated in the group policy.  Mechanisms implementing this policy
  must support the measurement of key lifetime and periodic PFS
  rekeying.


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  Limited lifetime rekeying is supported by the vast majority of
  existing secure multicast and group communication frameworks.  The
  mechanism requirements of this policy are simple and strait-forward.
  Finally, to avoid cryptanalysis of session keys, periodic rekeying
  is a good security practice.  Thus, support for limited lifetime
  rekeying is a likely requirement of the SMuG policy framework.

  3.1.2 Access Control Policy

  An access control policy states the identities/credentials, rights
  and responsibilities of each member of the group.  Access control in
  our current group model is defined by the roles assumed by group
  participants.  The specification, meaning, and mechanisms for
  assuming these roles is as defined above in section 2.2.

  Support for role defining access control policy is a requirement for
  the SMuG policy framework.

  3.1.3 Data Security Policy

  The canonical security policy, a data security policy states the
  security guarantees provided to application level messages.  This
  policy is likely to directly or indirectly state the data transforms
  defined by the SMuG problem area 1 group [CRC00] used to secure
  group messages.  Several data security guarantees include;

    confidentiality - Guarantee stating that no member outside the
    group can obtain the contents of a group message.

    integrity - Guarantee stating that any modification of a group
    message during transmission is detectable by the receiver.

    group authentication - Guarantee stating that a received message
    was transmitted by some member of the group.  This is typically a
    byproduct of other (data security) guarantees.

    source authentication (or sender authentication) - Guarantee
    stating that the sender of a message can be uniquely identified.
    Providing this guarantee in an efficient and scalable way is an
    open issue.  However, recent developments by Perrig et. al.
    [PSTC00] outline several promising solutions for providing
    efficient sender authentication.

    non-repudiation - Guarantee stating that a sender should not be
    able to falsely deny sending a previously transmitted message.

    anonymity - Guarantee stating that the originator of a message
    cannot be ascertained by receivers (or by outside parties).

  The cryptographic algorithms and used to provide these guarantees
  have varying strength and performance characteristics.  As such, a
  data-security policy should be able to state the algorithm(s) that
  may used to provide data security.  A result of the selection of

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  cryptographic algorithms leads to the following kinds of secrecy:

    ephemeral secrecy - the data be protected for (only) a short
    period after transmission.  That is, the algorithm should prevent
    easy access to content, but strong guarantees are not required.
    One example, from [CP99] is:

      [... to maintain ephemeral secrecy when transmitting a video it
      is sufficient to encrypt only the low-order Fourier coefficients
      in an MPEG encoding.]

    long-term secrecy - requirement that the transmitted data be
    protected for an indefinite period after transmission.  This
    requires strong cryptographic algorithms.

  A "cipher-suite" is one or more cryptographic algorithms used to
  implement data related guarantees.  The policy specification should
  allow, at a minimum, cipher suite definitions that support the
  specification of acceptable algorithm parameters and modes.
  Additionally, the suite definition should indicate the guarantees
  for which the suite should be used.

  Support for some, if not all, data security policies is a
  requirement of the SMuG policy framework.  A definition of the
  supported cipher suites should be developed by the multicast data
  transform specifications (level 1).

  3.1.4 Member-Data Policy

  A member-data policy indicates the availability of group membership
  information, states guarantees of the accuracy of this information,
  and identifies the mechanism used for its distribution.

  Identification of the membership within a group session is an
  important requirement for a large class of applications.  As
  evidenced by a number of group communication systems, achieving
  strong guarantees for the availability and correctness of group
  membership can be costly.  Several member-data policies worth
  considering are:

    best-effort member-data - In this policy, membership data will be
    delivered as available.  No guarantees about the accuracy or
    timeliness of this information are provided.  However,
    due-diligence should be expended in providing accurate membership
    data.

    positive member-data - This policy guarantees that all members in
    the membership data are actively participating in the group.  That
    is, a listed member is guaranteed to be receiving data and has not
    failed (see below, in Failure Policy 3.1.6, for a definition of a
    process failure).

    negative member-data - This policy guarantees that every member of

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    the current security context is listed in the membership data.

    perfect member-data - This policy guarantees that all members in
    the membership data actively participating in the group, and that
    every member of the current security context is listed in the
    membership data.  That is, both positive and negative member-data
    is provided.

  A related policy is confidentiality of group membership.  In
  general, hiding the group membership information from members and
  non-members is difficult to do in current networks.  This is
  primarily because the ability to monitor messages on the network
  allows access to the source and destination of packets (in case of
  unicasts) and at the multicast tree (in case of IP multicasts).  In
  mounting this traffic analysis attack, an adversary may deduce a
  close approximation of group membership.

  It is unclear if member-data policies are within the scope of the
  SMuG framework.  However, we note that the availability of accurate
  membership information is a pre-requisite of some reliable multicast
  solutions being discussed by the Reliable Multicast Research Group
  [RM].

  3.1.5 Compromise Policy

  A compromise policy identifies the types of compromises to be
  detected, the means by which they are reported, and the mechanism
  used for recovery.  Compromise related algorithms may or may not be
  protocol and keying algorithm dependent.  Further investigation of
  the requirements of these policies is required.

  It is unclear if compromise detection and recovery is within the
  scope of the SMuG framework.

  3.1.6 Failure Policy

  A failure policy defines what kinds of (member) failures are to be
  detected and the mechanisms used for failure detection, reporting,
  and recovery.  The definition of a failure policy should be derived
  from a process "crash model".  As defined in [Mul93], traditional
  crash models include;

    fail-stop - The failed process immediately and permanently stops
    sending and receiving messages.  The vast majority of secure group
    and multicast frameworks and protocols assume a fail-stop failure
    model, if any.

    message-omission - The failed process will not receive or send
    (omit) an arbitrary number of messages.

    Byzantine - The failed process can exhibit any behavior
    whatsoever.  A failed process in a Byzantine failure model should
    be assumed to be actively attempting to circumvent the security of

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    the group.  As demonstrated in RAMPART [Rei94] system, known
    mechanisms providing protection from Byzantine failures are both
    expensive and complex.  Note that mechanisms used to combat
    Byzantine failures are often similar to compromise recovery
    algorithms.

  Systems supporting failure detection and recovery techniques found
  in survivability and distributed systems literature typically do not
  address security.  Thus, the integration of these services with a
  security infrastructure requires careful design and analysis.  It is
  unclear if these policies should be addressed by the SMuG framework.

  3.1.7 Domain Dependent Policy

  A domain dependent policy dictates ways in which the security
  context may be effected by forces external to secure multicast
  services.  Such a policy would specify the modification of group
  behavior in response to the observation of an external event or
  state.

  An example of a domain dependent policy is the modification of group
  access rights during a launch window.  At the Kennedy Space Center
  (NASA), monitoring devices on the space shuttle continuously
  transmit data to a number of monitoring applications.  Outside a
  launch window, the applications may alter configuration or test
  devices as needed.  During the launch window, these devices transmit
  monitoring data, but access to configuration and testing interfaces
  is prohibited.  One group (domain dependent) policy supporting the
  requirements of this environment would state that no application
  should be able to send to the group during the launch window.
  Another policy would outright prohibit the (testing) applications
  from participating in the group during a launch window.

  Developing an enumeration of all potential domain dependent policies
  is infeasible.  Thus, if supported, flexible interfaces for
  reporting external events and state must be provided.  An open issue
  are the security requirements for the event detection and state
  assessment mechanisms.  A second issue is the support of domain
  dependent roles (such as the application role in the above example).

  At a minimum, it seems necessary for the secure multicast group to
  provide interfaces to secure group related activities.  Such
  activities may include (but are not restricted to); initiate
  rekeying, member ejection, and compromise recovery.

  3.2 Local Policy

  A local policy states the security and performance requirements of
  the local infrastructure on the SMuG framework.  The mechanism used
  for the specification and distribution of local policy is beyond the
  scope of this document.

  The following subsections define several dimensions along which a

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  local policy may be defined.

  3.2.1 Infrastructure Policy

  An infrastructure policy identifies the locally trusted entities and
  indicates which mechanisms may be used to obtain other credentials.
  In this, a statement of what groups the host is allowed to join may
  be implicitly specified.

  Typically, this policy is used to identify the identity, location,
  and mechanism of locally held credentials (e.g. long term keys).  It
  is from these credentials that access to the group services will be
  likely be obtained.  An example policy of this type may identify a
  file in the local filesystem that contains a long term key.  Note
  that the means in which the contents of the file is interpreted must
  also be specified.

  Conversely, the infrastructure will also state the means in which
  the identities and credentials received from the group will be
  verified (.e.g. location of locally trusted CA).  The identity of
  trusted framework components (e.g. policy distribution points) may
  also be specified.

  Support for infrastructure policy is a requirement of the SMuG
  framework.

  3.2.2 Policy Requirements
  
  This policy state the minimum services a host will accept.  In this,
  it may state the following requirements of any group:

    trusted entities - This policy states which parties may assume
    roles within the group.  For example, one policy may state that a
    local process may only join groups whose key controller is a
    specific host (e.g. antigone.citi.umich.edu).

    data security policies - This policy requires that groups provide
    particular data security policies.

    others - In general, any policy expressible in the group policy
    should be able to be stated as a policy requirement.

  Policy requirements are likely to drive any policy negotiation
  process.  Converging on a set of services that meet the requirements
  of all members is an open issue.

  Support for policy requirements is a requirement of the SMuG
  framework.

4. References

  [Bri99] Bob Briscoe, "MARKS: Zero Side-Effect Multicast Key
  Management Using Arbitrarily Revealed Key Sequences", In Proceedings

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  of First International Workshop on Networked Group Communication,
  November 1999.

  [CCP+99] R. Canetti, P-C. Cheng, D. Pendarakis, J.R. Rao, P.Rohatgi
  and D. Saha, "An Architecture for Secure Internet Multicast",
  Internet Engineering Task Force, February 1999,
  draft-irtf-smug-sec-mcast-arch-00.txt (Draft).

  [CP99] R. Canetti and B. Pinkas, "A Taxonomy of Multicast Security
  Issues (updated version)", Internet Research Task Force, April,
  1999, draft-irtf-smug-taxonomy-01.txt (Draft).

  [CRC00] Ran Canetti, Pankaj Rohatgi, and Pau-Chen Cheng, "Multicast
  Data Security Transformations: Requirements, Considerations, and
  Prominent Choices", Internet Engineering Task Force, May 2000,
  draft-data-transforms.txt (Draft).

  [DBH+00] P. Dinsmore, D. Balenson, M. Heyman, P. Kruus, C Scace, and
  A. Sherman "Policy-Based Security Management for Large Dynamic
  Groups: A Overview of the DCCM Project", In Proceedings of DARPA
  Information Survivability Conference and Exposition (DISCEX '00),
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McDaniel, Harney, Dinsmore, and Prakash                       [Page 15]

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Authors' addresses:

Patrick McDaniel
Department of Electrical Engineering and Computer Science
University of Michigan
3115 EECS Building
1301 Beal Avenue
Ann Arbor, MI 48109
pdmcdan@eecs.umich.edu

Hugh Harney
Sparta
9861 Broken Land Parkway
Columbia, MD 21046
(410) 381-9400 x203
hh@sparta.com

Peter Dinsmore
NAI Labs
3060 Washington Road,
Glenwood, MD 21738
(443) 259-2346
Pete_Dinsmore@NAI.com

Atul Prakash
Department of Electrical Engineering and Computer Science
University of Michigan
2231 EECS Building 
1301 Beal Avenue 
(734) 763-1585 
aprakash@eecs.umich.edu 




------------------------------------------------------------------------
Thomas Hardjono       email1: thardjono@yahoo.com
                      email2: hardjono@nortelnetworks.com
                      Tel: +1-978-288-4538   
------------------------------------------------------------------------


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