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IDTRUST Tables of Contents: 080910

Proceedings of the 2010 Symposium on Identity and Trust on the Internet

Fullname:Proceedings of the 9th symposium on Identity and trust on the Internet
Editors:Ken Klingenstein; Carl Ellison
Location:Gaithersburg, Maryland
Dates:2010-Apr-13 to 2010-Apr-15
Standard No:ISBN: 1-60558-895-4, 978-1-60558-895-7; ACM DL: Table of Contents hcibib: IDTRUST10
Links:Conference Home Page
  1. Identity providers and federation
  2. Policy conflict resolution
  3. Privacy
  4. Biometrics
  5. Infrastructure

Identity providers and federation

Federated login to TeraGrid BIBAKFull-Text 1-11
  Jim Basney; Terry Fleury; Von Welch
We present a new federated login capability for the TeraGrid, currently the world's largest and most comprehensive distributed cyberinfrastructure for open scientific research. Federated login enables TeraGrid users to authenticate using their home organization credentials for secure access to TeraGrid high performance computers, data resources, and high-end experimental facilities. Our novel system design links TeraGrid identities with campus identities and bridges from SAML to PKI credentials to meet the requirements of the TeraGrid environment.
Keywords: GridShib, MyProxy, PKI, SAML, Shibboleth, TeraGrid, grid computing, identity federation
CardSpace-liberty integration for CardSpace users BIBAKFull-Text 12-25
  Haitham S. Al-Sinani; Waleed A. Alrodhan; Chris J. Mitchell
Whilst the growing number of identity management systems have the potential to reduce the threat of identity attacks, major deployment problems remain because of the lack of interoperability between such systems. In this paper we propose a novel scheme to provide interoperability between two of the most widely discussed identity management systems, namely Microsoft CardSpace and Liberty. In this scheme, CardSpace users are able to obtain an assertion token from a Liberty-enabled identity provider that will satisfy the security requirements of a CardSpace-enabled relying party. We specify the operation of the integration scheme and also describe an implementation of a proof-of-concept prototype. Additionally, security and operational analyses are provided.
Keywords: CardSpace, Liberty Alliance project, SAML, browser extension, identity management, interoperability
An identity provider to manage reliable digital identities for SOA and the web BIBAKFull-Text 26-36
  Ivonne Thomas; Christoph Meinel
In this paper, we describe the implementation of our identity provider, based on open web service standards, which has been extended to distinguish between different qualities of identity attributes; therefore enabling a relying party to distinguish between verified and unverified digital identities.
   Our contribution is the definition and representation of identity meta information for identity attributes on the identity provider side and the conveyance of this information as Identity Attribute Context Classes to a relying party. As a main result, we propose a format and semantic to include identity attribute meta information into security token which are sent from the identity provider to a relying party in addition to the attribute value itself.
Keywords: SOA security, attribute management, identity management, identity provider

Policy conflict resolution

An attribute-based authorization policy framework with dynamic conflict resolution BIBAKFull-Text 37-50
  Apurva Mohan; Douglas M. Blough
Policy-based authorization systems are becoming more common as information systems become larger and more complex. In these systems, to authorize a requester to access a particular resource, the authorization system must verify that the policy authorizes the access. The overall authorization policy may consist of a number of policy groups, where each group consists of policies defined by different entities. Each policy contains a number of authorization rules. The access request is evaluated against these policies, which may produce conflicting authorization decisions. To resolve these conflicts and to reach a unique decision for the access request at the rule and policy level, rule and policy combination algorithms are used. In the current systems, these rule and policy combination algorithms are defined on a static basis during policy composition, which is not desirable in dynamic systems with fast changing environments.
   In this paper, we motivate the need for changing the rule and policy combination algorithms dynamically based on contextual information. We propose a framework that supports this functionality and also eliminates the need to recompose policies if the owner decides to change the combination algorithm. It provides a novel method to dynamically add and remove specialized policies, while retaining the clarity and modularity in the policies. The proposed framework also provides a mechanism to reduce the set of potential target matches, thereby increasing the efficiency of the evaluation mechanism. We developed a prototype system to demonstrate the usefulness of this framework by extending some basic capabilities of the XACML policy language. We implemented these enhancements by adding two specialized modules and several new combination algorithms to the Sun XACML engine.
Keywords: attribute-based authorization, authorization policy, conflict resolution
Computational techniques for increasing PKI policy comprehension by human analysts BIBAKFull-Text 51-62
  Gabriel A. Weaver; Scott Rea; Sean W. Smith
Natural-language policies found in X.509 PKI describe an organization's stated policy as a set of requirements for trust. The widespread use of X.509 underscores the importance of understanding these requirements. Although many review processes are defined in terms of the semantic structure of these policies, human analysts are confined to working with page-oriented PDF texts. Our research accelerates PKI operations by enabling machines to translate between policy page numbers and policy reference structure. Adapting technologies supporting the analysis of Classical texts, we introduce two new tools. Our Vertical Variance Reporter helps analysts efficiently compare the reference structure of two policies. Our Citation-Aware HTML enables machines to process human-readable displays of policies in terms of this reference structure. We evaluate these contributions in terms of real-world feedback and observations from organizations that audit or accredit policies.
Keywords: PKI, XML, certificate policy formalization


Efficient and privacy-preserving enforcement of attribute-based access control BIBAKFull-Text 63-68
  Ning Shang; Federica Paci; Elisa Bertino
Modern access control models, developed for protecting data from accesses across the Internet, require to verify the identity of users in order to make sure that users have the required permissions for accessing the data. User's identity consists of data, referred to as identity attributes, that encode relevant-security properties of the users. Because identity attributes often convey sensitive information about users, they have to be protected. The Oblivious Commitment-Based Envelope (OCBE) protocols address the protection requirements of both users and service providers. The OCBE protocols makes it possible for a party, referred as sender, to send an encrypted message to a receiver such that the receiver can open the message if and only if its committed value satisfies a predicate and that the sender does not learn anything about the receiver's committed value. The possible predicates are comparison predicates =, ≠, >, <, ≤, ≥. In this paper, we present an extension that improves the efficiency of EQ-OCBE protocol, that is, the OCBE protocol for equality predicates. Our extension allows a party to decrypt data sent by a service provider if and only if the party satisfies all the equality conditions in the access control policy.
Keywords: Agg-EQ-OCBE, identity, privacy
Privacy-preserving DRM BIBAKFull-Text 69-83
  Radia Perlman; Charlie Kaufman; Ray Perlner
This paper describes and contrasts two families of schemes that enable a user to purchase digital content without revealing to anyone what item he has purchased. One of the basic schemes is based on anonymous cash, and the other on blind decryption. In addition to the basic schemes, we present and compare enhancements to the schemes for supporting additional features such as variable costs, enforcement of access restrictions (such as "over age 21"), and the ability of a user to monitor and prevent covert privacy-leaking between a content-provider-provided box and the content provider. As we will show, the different variants have different properties in terms of amount of privacy leaking, efficiency, and ability for the content provider to prevent sharing of encryption keys or authorization credentials.
Keywords: DRM, algorithms, blindable parameterizable public key, privacy, protocols


Biometrics-based identifiers for digital identity management BIBAKFull-Text 84-96
  Abhilasha Bhargav-Spantzel; Anna Squicciarini; Elisa Bertino; Xiangwei Kong; Weike Zhang
We present algorithms to reliably generate biometric identifiers from a user's biometric image which in turn is used for identity verification possibly in conjunction with cryptographic keys. The biometric identifier generation algorithms employ image hashing functions using singular value decomposition and support vector classification techniques. Our algorithms capture generic biometric features that ensure unique and repeatable biometric identifiers. We provide an empirical evaluation of our techniques using 2569 images of 488 different individuals for three types of biometric images; namely fingerprint, iris and face. Based on the biometric type and the classification models, as a result of the empirical evaluation we can generate biometric identifiers ranging from 64 bits up to 214 bits. We provide an example use of the biometric identifiers in privacy preserving multi-factor identity verification based on zero knowledge proofs. Therefore several identity verification factors, including various traditional identity attributes, can be used in conjunction with one or more biometrics of the individual to provide strong identity verification. We also ensure security and privacy of the biometric data. More specifically, we analyze several attack scenarios. We assure privacy of the biometric using the one-way hashing property, in that no information about the original biometric image is revealed from the biometric identifier.
Keywords: biometrics, cryptography, identity, multi-factor authentication, privacy, security


Practical and secure trust anchor management and usage BIBAKFull-Text 97-107
  Carl Wallace; Geoff Beier
Public Key Infrastructure (PKI) security depends upon secure management and usage of trust anchors. Unfortunately, widely used mechanisms, management models and usage practices related to trust anchors undermine security and impede flexibility. In this paper, we identify problems with existing mechanisms, discuss emerging standards and describe a solution that integrates with some widely used applications.
Keywords: public key infrastructure (PKI), trust anchor management
A proposal for collaborative internet-scale trust infrastructures deployment: the public key system (PKS) BIBAKFull-Text 108-116
  Massimiliano Pala
Public Key technology is about multiple parties across different domains making assertions that can be chained together to make trust judgments. Today, the need for more interoperable and usable trust infrastructures is urgent in order to fulfill the security needs of computer and mobile devices. Developing, deploying, and maintaining information technology that provides effective and usable solutions has yet to be achieved. In this paper, we propose a new framework for a distributed support system for trust infrastructure deployment: the Public Key System (PKS). We describe the general architecture based on Distributed Hash Tables (DHTs), how it simplifies the deployment and usability of federated identities, and how existing infrastructures can be integrated into our system. This paper lays down the basis for the deployment of collaborative Internet-scale trust infrastructures.
Keywords: PKI, distributed systems, federated identities, peer-to-peer