Taxonomy for and Analysis of Anonymous Communications Networks

257 Pages·2009·3.54 MB·English

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A TAXONOMY FOR AND ANALYSIS OF
ANONYMOUS COMMUNICATIONS NETWORKS

DISSERTATION

Douglas Kelly, GG-14

AFIT/DCS/ENG/09-08

AIR FORCE INSTITUTE OF TECHNOLOGY

Wright-Patterson Air Force Base, Ohio

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED
The views expressed in this dissertation are those of the author and do not reflect the
official policy or position of the United States Air Force, Department of Defense, or the
U.S. Government.
A TAXONOMY FOR AND ANALYSIS OF
ANONYMOUS COMMUNICATIONS NETWORKS

DISSERTATION

Presented to the Faculty
Graduate School of Engineering and Management
Air Force Institute of Technology
Air University
Air Education and Training Command
In Partial Fulfillment of the Requirements for the
Degree of Doctor of Philosophy

Douglas J. Kelly, BS, MS, MBA

March 2009

APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED
AFIT/DCS/ENG/09-08
A TAXONOMY FOR AND ANALYSIS OF
ANONYMOUS COMMUNICATIONS NETWORKS

DISSERTATION

Douglas J. Kelly, BS, MS, MBA

Approved:

__________//SIGNED//________________ _16 Mar 09_
Dr. Richard A. Raines (Chairman) Date

__________//SIGNED//________________ _16 Mar 09_
Dr. Barry E. Mullins (Member) Date

__________//SIGNED//________________ _16 Mar 09_
Dr. Rusty O. Baldwin (Member) Date

__________//SIGNED//________________ _16 Mar 09_
Dr. Michael R. Grimaila (Member) Date

Accepted:

__________//SIGNED//________________ _18 Mar 09_
Dr. M. U. Thomas Date
Dean, Graduate School of
Engineering and Management

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AFIT/DCS/ENG/09-08
Abstract
Any entity operating in cyberspace is susceptible to debilitating attacks. With cyber attacks
intended to gather intelligence and disrupt communications rapidly replacing the threat of
conventional and nuclear attacks, a new age of warfare is at hand. In 2003, the United States
acknowledged that the speed and anonymity of cyber attacks makes distinguishing among the
actions of terrorists, criminals, and nation states difficult. Even President Obama’s Cybersecurity
Chief-elect recognizes the challenge of increasingly sophisticated cyber attacks. Now through
April 2009, the White House is reviewing federal cyber initiatives to protect US citizen privacy
rights. Indeed, the rising quantity and ubiquity of new surveillance technologies in cyberspace
enables instant, undetectable, and unsolicited information collection about entities. Hence,
anonymity and privacy are becoming increasingly important issues. Anonymization enables
entities to protect their data and systems from a diverse set of cyber attacks and preserves privacy.
This research provides a systematic analysis of anonymity degradation, preservation and
elimination in cyberspace to enhance the security of information assets. This includes
discovery/obfuscation of identities and actions of/from potential adversaries. First, novel
taxonomies are developed for classifying and comparing well-established anonymous networking
protocols. These expand the classical definition of anonymity and capture the peer-to-peer and
mobile ad hoc anonymous protocol family relationships. Second, a unique synthesis of state-of-
the-art anonymity metrics is provided. This significantly aids an entity’s ability to reliably
measure changing anonymity levels; thereby, increasing their ability to defend against cyber
attacks. Finally, a novel epistemic-based mathematical model is created to characterize how an
adversary reasons with knowledge to degrade anonymity. This offers multiple anonymity
property representations and well-defined logical proofs to ensure the accuracy and correctness of
current and future anonymous network protocol design.
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AFIT/DCS/ENG/09-08
Acknowledgments
Special thanks go to my advisor and committee members who were extremely
supportive during some very difficult times while pursuing this degree. Succinctly, my
committee members and agency executive support enabled me to grow professionally
and contribute eight academic papers in my field.
Most PhD candidates deservedly praise their wives and/or significant others for their
tremendous love, support, and understanding while advancing their career. I am able to
attest to the significant advantage such support provides for I had no such personal
support to draw strength from. Nonetheless, I acknowledge God for giving me the
fortitude to continue to make progress in my studies and ultimately become successful
during this challenging but rewarding academic experience.

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Table of Contents
Abstract .............................................................................................................................. iv
Acknowledgments.............................................................................................................. iv
Table of Contents ............................................................................................................... vi
List of Figures .................................................................................................................. xiv
List of Tables ................................................................................................................... xiv
List of Acronyms .............................................................................................................. xv
I. Introduction ................................................................................................................. 1
1.0 Background .......................................................................................................... 1
1.1 Problem Statement ............................................................................................... 3
1.2 Research Objectives ............................................................................................. 4
1.3 Assumptions/Limitations ..................................................................................... 5
1.4 Implications.......................................................................................................... 6
1.5 Summary .............................................................................................................. 6
II. Literature Review........................................................................................................ 8
2.0 Chapter Overview ................................................................................................ 8
2.1 Background .......................................................................................................... 8
2.1.1 Privacy. ......................................................................................................... 9
2.1.2 Identity. ....................................................................................................... 11
2.1.3 Anonymity. ................................................................................................. 11
2.1.3.1 Advantages. .......................................................................................... 13
2.1.3.2 Disdvantages. ....................................................................................... 15
2.1.4 Pseudonymity. ............................................................................................. 17
2.1.5 Reputation. .................................................................................................. 18
2.1.5.1 eBay. .................................................................................................... 18
2.2 Nomenclature ..................................................................................................... 19
2.2.1 Fundamental Anonymity Properties. .......................................................... 19
2.2.2 The Adversary. ............................................................................................ 23
2.2.3 The Attacks. ................................................................................................ 24
2.2.4 The Mix. ...................................................................................................... 27
2.3 Anonymous Networks ....................................................................................... 33
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2.3.1 Wired Networks. ......................................................................................... 34
2.3.1.1 Anonymizer.......................................................................................... 34
2.3.1.2 Java Anon Proxy. ................................................................................. 35
2.3.1.3 PipeNet. ................................................................................................ 35
2.3.1.4 Onion Routing (Tor). ........................................................................... 36
2.3.1.5 Freedom Network. ............................................................................... 37
2.3.1.6 Cyberpunk (Type I remailer). .............................................................. 37
2.3.1.7 Mixmaster (Type II remailer). ............................................................. 38
2.3.1.8 Mixminion (Type III remailer). ........................................................... 38
2.3.1.9 DC-Net. ................................................................................................ 39
2.3.1.10 Herbivore. .......................................................................................... 39
2.3.1.11 Crowds. .............................................................................................. 40
2.3.1.12 Hordes. ............................................................................................... 40
2.3.1.13 P5. ....................................................................................................... 40
2.3.1.14 Tarzan. ............................................................................................... 41
2.3.1.15 WonGoo. ............................................................................................ 41
2.3.1.16 Cashmere............................................................................................ 41
2.3.1.17 MAM.................................................................................................. 42
2.3.2 Wireless Networks. ..................................................................................... 42
2.3.2.1 SDAR. .................................................................................................. 44
2.3.2.2 AnonDSR. ............................................................................................ 44
2.3.2.3 MASK. ................................................................................................. 45
2.3.2.4 ARM. ................................................................................................... 45
2.3.2.5 ODAR. ................................................................................................. 46
2.3.2.6 AMUR.................................................................................................. 46
2.3.2.7 HANOR. .............................................................................................. 47
2.3.2.8 ANODR. .............................................................................................. 47
2.3.2.9 SDDR. .................................................................................................. 48
2.3.2.10 ASR. ................................................................................................... 48
2.3.2.11 ZAP. ................................................................................................... 49
2.3.2.12 AODPR. ............................................................................................. 49
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2.3.2.13 AO2P.................................................................................................. 50
2.3.2.14 SAS. ................................................................................................... 50
2.3.2.15 ASC. ................................................................................................... 50
2.3.2.16 ASRPAKE. ........................................................................................ 51
2.4 Quantifying Anonymity ..................................................................................... 51
2.4.1 Anonymity Set Size. ................................................................................... 52
2.4.2 Individual Anonymity Degree. ................................................................... 53
2.4.3 Entropy Anonymity. ................................................................................... 54
2.4.3.1 Effective Anonymity Set Size. ............................................................. 56
2.4.4 Normalized Entropy Anonymity Degree. ................................................... 59
2.4.5 Negligibility-based Identity-free Anonymity. ............................................ 61
2.4.6 Localized Real-time Anonymity. ................................................................ 63
2.4.7 Combinatorial Anonymity Degree. ............................................................. 66
2.4.8 Evidence Theory Anonymity. ..................................................................... 69
2.4.9 k-Anonymity. .............................................................................................. 73
2.4.9.1 Data Privacy k-Anonymity. ................................................................. 74
2.4.9.2 Destination k-Anonymity Zone. .......................................................... 75
2.4.9.3 Personalized Location k-Anonymity. ................................................... 80
2.4.10 Multicast Anonymity. ............................................................................... 83
2.5 Formalizing Anonymity ..................................................................................... 86
2.5.1 Conceptual Framework. .............................................................................. 90
2.5.1.1 Group Support System Framework. .................................................... 91
2.5.1.2 Collaborative Peer Group Framework. ................................................ 92
2.5.1.3 Connection Anonymity Framework. ................................................... 94
2.5.1.4 Summary. ............................................................................................. 96
2.5.2 Probabilistic and Nondeterministic Systems. ............................................. 97
2.5.3 Group Principals. ........................................................................................ 99
2.5.4 Multi-agent Systems. ................................................................................ 101
2.6 Logics ............................................................................................................... 104
2.6.1 Modal Logics. ........................................................................................... 105
2.6.2 Epistemic Logic. ....................................................................................... 107
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2.6.3 KT45n Logic.............................................................................................. 108
2.6.3.1 KT45n Syntax. ................................................................................... 108
2.6.3.2 KT45n Rules. ...................................................................................... 109
2.6.3.3 KT45n Semantics. .............................................................................. 113
2.6.4 Logical Posibilistic Anonymity. ............................................................... 114
2.6.5 Logical Probabilistic Anonymity. ............................................................. 116
2.6.6 Temporal Logics. ...................................................................................... 117
2.7 Process Calculi ................................................................................................. 119
2.7.1 Communications Sequential Processes (CSP). ......................................... 119
2.7.1.1 System Model. ................................................................................... 120
2.7.1.2 Applications. ...................................................................................... 122
2.7.2 π-Calculus. ................................................................................................ 123
2.7.2.1 Syntax. ............................................................................................... 124
2.7.2.2 Semantics. .......................................................................................... 125
2.7.2.3 Variants and Applications. ................................................................. 125
2.7.3 Comparison. .............................................................................................. 126
2.8 Function Views ................................................................................................ 128
2.8.1 Function Knowledge. ................................................................................ 128
2.8.2 Opaqueness. .............................................................................................. 129
2.8.3 Modular Approach. ................................................................................... 130
2.9 Summary .......................................................................................................... 132
III. Methodology ....................................................................................................... 134
3.0 Chapter Overview ............................................................................................ 134
3.1 Motivation ........................................................................................................ 134
3.1.1 Develop Anonymous Network Taxonomy. .............................................. 137
3.1.2 Evaluate Emerging Anonymity Metrics. .................................................. 137
3.1.3 Create a Formal Model. ............................................................................ 138
3.2 Summary .......................................................................................................... 139
IV. Anonymous Network Taxonomy Analysis and Results ..................................... 140
4.0 Chapter Overview ............................................................................................ 140
4.1 Anonymity Properties ...................................................................................... 140
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