Privacy and Identity Management in Cloud

Rohit Ranchal, Bharat Bhargava, Pelin Angin, Noopur Singh, Lotfi Ben Othmane, Leszek Lilien Department of Computer Science Purdue University, Western Michigan University {rranchal, bbshail}@purdue.edu, [email protected]

Mark Linderman [email protected]

Air Force Research Laboratory Rome, NY, USA This research was supported by AFRL Rome, USA and NGC

Outline

         Motivation Identity Management (IDM) Goals of Proposed User-Centric IDM Mechanisms Description of proposed solution Advantages of the Proposed Scheme Conclusion & Future Work References Questions?

Motivation

User on Amazon Cloud • • • • • • Name E-mail Password Billing Address Shipping Address Credit Card • • • • • • Name E-mail Password Billing Address Shipping Address Credit Card • • • Name Billing Address Credit Card • • • Name E-mail Shipping Address • • • Name E-mail Shipping Address

Motivation

User on Amazon Cloud • • • • • • Name E-mail Password Billing Address Shipping Address Credit Card • • • • • • Name E-mail Password Billing Address Shipping Address Credit Card • • • Name Billing Address Credit Card • • • Name E-mail Shipping Address • • • Name E-mail Shipping Address

Motivation

    The migration of web applications to Cloud computing platform has raised concerns about the privacy of sensitive data belonging to the consumers of cloud services.

How can consumers verify that a service provider conform to the privacy laws and protect consumer’s digital identity.

The username/password security token used by most service providers to authenticate consumers, leaves the consumer vulnerable to phishing attacks.

The solution to address the above problems can be the use of an Identity Management (IDM) System. The solution should help the consumer in making a proactive choice about how and what personal information they disclose, control how their information can be used, cancel their subscription to the service, and monitor to verify that a service provider applies required privacy policies.

 ◦  ◦ ◦ ◦

Identity Management (IDM)

IDM in traditional application-centric IDM model Each service keeps track of identifying information of its users. Existing IDM Systems Microsoft Windows CardSpace [W. A. Alrodhan] OpenID [http://openid.net] PRIME [S. F. Hubner, Karlstad Univ] These systems require a an untrusted host.

trusted third party

and do not work on If Trusted Third Party is compromised, all the identifying information of the users is also compromised leading to serious problems like

Identity Theft.

[AT&T iPad leak ]

Identity Management (IDM)

 Microsoft Windows CardSpace Windows CardSpace is an Identity-metasystem which provides a way, for managing multiple digital identities of a user. It is claims based access platform/ architecture, developed for windows XP. It uses a plug-in for Internet explorer 7 browser.

 OpenID With OpenID a user uses one username and one password to access many web applications. The user authenticate to an OpenID server to get his/her OpenID token in order to authenticate itself to web applications.

 PRIME (Privacy and Identity Management for Europe) PRIME, is an application -the PRIME Console middleware running on a user’s machine, It handles management and disclosure of personal data for the user.

IDM in Cloud Computing

 Cloud introduces several issues to IDM ◦ Collusion between Cloud Services  Users have

multiple accounts providers.

associated with

multiple service

◦ ◦  Sharing sensitive identity information between services can lead to undesirable

mapping of the identities to the user.

Lack of trust  Cloud hosts are untrusted  Use of Trusted Third Party is not an option Loss of control  Service-centric IDM Model

IDM in Cloud needs to be user-centric

1.

2.

3.

4.

Goals of Proposed User-Centric IDM for the Cloud

Authenticate without disclosing identifying information Ability to securely use a service while on an untrusted host (VM on the cloud) Minimal disclosure and minimized risk of disclosure during communication between user and service provider (Man in the Middle, Side Channel and Correlation Attacks) Independence of Trusted Third Party for identity information

Mechanisms in Proposed IDM

     Active Bundle [L. Othmane, R. Ranchal] Anonymous Identification [A. Shamir] Computing Predicates with encrypted data [E. Shi] Multi-Party Computing [A. Shamir] Selective Disclosure [B. Laurie]

• •

Active Bundle

Active bundle ( AB ) – An encapsulating mechanism protecting data carried within – – – Includes data Includes metadata • used for managing confidentiality Both privacy of data and privacy of the whole AB Includes Virtual Machine (VM) • performing a set of operations • protecting its confidentiality Active Bundles—Operations – Self-Integrity check E.g., Uses a hash function – Evaporation/ Filtering Self-destroys (a part of) AB’s sensitive data when threatened with a disclosure – Apoptosis Self-destructs AB’s completely

Active Bundle Scheme

• • • • • • • E(Name) E(E-mail) E(Password) E(Shipping Address) E(Billing Address) E(Credit Card) … – Metadata: • Access control policies • • • • • • • Data integrity checks Dissemination policies Life duration ID of a trust server ID of a security server App-dependent information … – Sensitive Data: • Identity Information • ...

– Virtual Machine (algorithm): • Interprets metadata • • • Checks active bundle integrity Enforces access and dissemination control policies …

* E( ) - Encrypted Information

•

Anonymous Identification

Use of Zero-knowledge proofing for user authentication without disclosing its identifier.

User on Amazon Cloud 1. E-mail 2. Password

ZKP Interactive Protocol

User Request for service Function f and number k f k (E-mail, Password) = R

Authenticated

1. E-mail 2. Password

Interaction using Active Bundle

AB information disclosure Active Bundle Destination

User Application

Active Bundle Creator Active Bundle (AB) Active Bundle Security Services Agent (SSA) Directory Facilitator

Active Bundle Coordinator

Trust Evaluation Agent (TEA)

Active Bundle Services

Audit Services Agent (ASA)

Predicate over Encrypted Data

• Verification without disclosing unencrypted identity data.

• • • • • • E-mail Password E(Name) E(Shipping Address) E(Billing Address) E(Credit Card) Predicate Request* • • • E(Name) E(Billing Address) E(Credit Card) *Age Verification Request *Credit Card Verification Request

•

Multi-Party Computing

• • To become independent of a trusted third party Multiple Services hold shares of the secret key Minimize the risk Predicate Request • • • E(Name) E(Billing Address) E(Credit Card) K ’ 1 K ’ 2 K ’ 3 Key Management Services K ’ n * Decryption of information is handled by the Key Management services

Multi-Party Computing

• • • To become independent of a trusted third party Multiple Services hold shares of the secret key Minimize the risk Predicate Reply* • • • Name Billing Address Credit Card K ’ 1 *Age Verified *Credit Card Verified K ’ 2 K ’ 3 Key Management Services K ’ n

Selective Disclosure

• User Policies in the Active Bundle dictate dissemination • • • • • • E-mail Password E(Name) E(Shipping Address) E(Billing Address) E(Credit Card) Selective disclosure* • • • E-mail E(Name) E(Shipping Address) *e-bay shares the encrypted information based on the user policy

Selective Disclosure

• • • E-mail E(Name) E(Shipping Address) Selective disclosure* • • E(Name) E(Shipping Address) *e-bay seller shares the encrypted information based on the user policy

Selective Disclosure

• • • E-mail E(Name) E(Shipping Address) Selective disclosure • • Name Shipping Address • Decryption handled by Multi-Party Computing as in the previous slides

Selective Disclosure

• • • E-mail E(Name) E(Shipping Address) Selective disclosure • • Name Shipping Address • Fed-Ex can now send the package to the user

Identity in the Cloud

User on Amazon Cloud • • E-mail Password • • • • • • Name E-mail Password Billing Address Shipping Address Credit Card • • Name Shipping Address • • • • E-mail Name Billing Address Credit Card

   

Characteristics and Advantages

• • Ability to use Identity data on untrusted hosts Self Integrity Check Integrity compromised- apoptosis or evaporation • Data should not be on this host ◦ ◦ Establishes the trust of users in IDM Through putting the user in control of who has his data and how is is used Identity is being used in the process of authentication, negotiation, and data exchange.

◦ Independent of Third Party for Identity Information Minimizes correlation attacks ◦ Minimal disclosure to the SP SP receives only necessary information.

Conclusion & Future Work

   ◦ ◦ Problems with IDM in Cloud Computing ◦ Collusion of Identity Information Prohibited Untrusted Hosts Usage of Trusted Third Party ◦ ◦ Proposed Approaches ◦ IDM based on Anonymous Identification IDM based on Predicate over Encrypted data IDM based on Multi-Party Computing Future work ◦ Develop the prototype, conduct experiments and evaluate the approach

References

[1] C. Sample and D. Kelley. Cloud Computing Security: Routing and DNS Threats, http://www.securitycurve.com/wordpress/, June 23,2009.

[2] W. A. Alrodhan and C. J. Mitchell. Improving the Security of CardSpace, EURASIP Journal on Information Security Vol. 2009, doi:10.1155/2009/167216, 2009.

[3] OPENID, http://openid.net/, 2010.

[4] S. F. Hubner. HCI work in PRIME, https://www.prime-project.eu/, 2008.

[5] A. Gopalakrishnan, Cloud Computing Identity Management, SETLabsBriefings, Vol7, http://www.infosys.com/research/, 2009.

[6] A. Barth, A. Datta, J. Mitchell and H. Nissenbaum. Privacy and Contextual

Integrity: Framework and Applications, Proc. of the 2006 IEEE Symposium on Security and Privacy, 184-198.

[7] L. Othmane, Active Bundles for Protecting Confidentiality of Sensitive Data throughout Their Lifecycle, PhD Thesis, Western Michigan Univ, 2010.

[8] A. Fiat and A. Shamir, How to prove yourself: Practical Solutions to Identification and Signature Problems, CRYPTO, 1986.

[9] A. Shamir, How to Share a Secret, Communications of the ACM, 1979.

[10] M. Ben-Or, S. Goldwasser and A. Wigderson, Completeness theorems for non- cryptographic fault-tolerant distributed computation, ACM Symposium on Theory of Computing, 1988. [11] E. Shi, Evaluating Predicates over Encrypted Data, PhD Thesis, CMU, 2008.

Thank you!

Any question?

Approach - 1

 ◦

IDM Wallet:

Use of AB scheme to protect PII from untrusted hosts.

 ◦

Anonymous Identification:

Use of Zero-knowledge proofing for authentication of an entity without disclosing its identifier.

    

Components of Active Bundle (Approach – 1)

Identity data: Data used during authentication, getting service, using service (i.e. SSN, Date of Birth). Disclosure policy: A set of rules for choosing Identity data from a set of identities in IDM Wallet. Disclosure history: Used for logging and auditing purposes.

Negotiation policy: This is Anonymous Identification, based on the Zero Knowledge Proofing. Virtual Machine: Code for protecting data on untrusted hosts. It enforces the disclosure policies.

Anonymous Identification (Approach – 1)

Anonymous Identification

(Shamir's approach for Credit Cards)   IdP provides Encrypted Identity Information to the user and SP. SP and User interact   Both run IdP's public function on the certain bits of the Encrypted data. Both exchange results and agree if it matches.

Usage Scenario (Approach – 1)

Approach - 2

   Active Bundle scheme from untrusted hosts to protect PII Predicates over encrypted data authenticate without disclosing unencrypted identity data.

to Multi-party computing of a trusted third party to be independent

     

Usage Scenario (Approach – 2)

Owner O encrypts Identity Data(PII) using algorithm Encrypt and O’s public key PK. Encrypt outputs CT—the encrypted PII. SP transforms his request for PII to a predicate represented by function p.

SP sends shares of p to the n parties who hold the shares of MSK. n parties execute together KeyGen using PK, MSK, and p, and return TKp to SP. SP calls the algorithm Query that takes as input PK, CT, TKp and produces p(PII) which is the evaluation of the predicate.

The owner O is allowed to use the service only when the predicate evaluates to “true”.

Representation of identity information for negotiation

 Token/Pseudonym  Identity Information in clear plain text 

Active Bundle

Motivation: Authentication Process using PII

Problem: Which information to disclose and how to disclose it.