Reflects the entire details about the IEEE paper along with the basics of Cloud. So as to understand the paper and the efforts put in by the authors.

1. Protection of Identity Information in
Cloud Computing without Trusted
Third Party
Authors:
Rohit Ranchal, Bharat Bhargave , Lotfi Ben Othmane, Leszek
Lilien, Anya Kim, Myong Kang, Mark Linderman
IEEE International Symposium on Reliable Distributed System
Presented by
Mithil S. Parab
Roll No:122113013
Seat No: 11
Guide: Prof. Nitesh Naik
06-03-2014
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2. Outline
Introduction
 Relate works
 Select research problems
 Proposed schemes

◦ Multi-party computing
◦ Predicate encryption scheme
◦ Active Bundle Scheme

Conclusions
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3. Definition of cloud computing - (NIST)

Cloud computing is a model for enabling
convenient, on-demand network access to a shared
pool of configurable computing resources (e.g.,
networks, servers, storage, applications, and
services) that can be rapidly provisioned and
released with minimal management effort or
service provider interaction
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4. Larry Ellison- CEO, Oracle
“The computer industry is the only
industry that is more fashion-driven than
women's fashion”
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5. Tely HD Pro – integration
 Blue Jeans Network
 Mobical – cloud provider used to sync mobile
phone data over the air.

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6. Cloud Architecture
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7. Type of Cloud Computing
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8. Cloud Service Layers - Characteristics
Software as a
Service (SaaS)
• Sometimes free; easy to use; good consumer adoption;
proven business models
• You can only use the application as far as what it is
designed for
Platform as a
Service (PaaS)
• Developers can upload a configured applications and it
“runs” within the platform’s framework;
• Restricted to the platform’s ability only; sometimes
dependant on Cloud Infrastructure provider
Infrastructure as
a Service (IaaS)
• Offers full control of a company’s infrastructure; not
confined to applications or restrictive instances
• Sometimes comes with a price premium; can be
complex to build, manage and maintain
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9. Cloud Service Layers - Containing
Software as a
Service (SaaS)
Platform as a
Service (PaaS)
Infrastructure as
a Service (IaaS)
Business Processes
Industry Applications
CRM/ERP/HR
Middleware
Development Tooling
Servers
Networking
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Database
Storage
Java Runtime
Data Center
Fabric
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10. Cloud Service Layers - Example
Software as a
Service (SaaS)
Platform as a
Service (PaaS)
Infrastructure as
a Service (IaaS)
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11. DEPLOYMENT MODELS
Public Cloud
Private Cloud
Hybrid Cloud
Public Cloud
 Computing infrastructure is hosted by cloud
vendor at the vendors premises.
 and can be shared by various organizations.
 E.g. : Amazon, Google, Microsoft, Sales force
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12. DEPLOYMENT MODELS
Public Cloud
Private Cloud
Hybrid Cloud
Private Cloud
 The computing infrastructure is dedicated to a
particular organization and not shared with other
organizations.
 more expensive and more secure when compare to
public cloud.
 E.g. : HP data center, IBM, Sun, Oracle, 3tera
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13. DEPLOYMENT MODELS
Public Cloud
Private Cloud
Hybrid Cloud
Hybrid Cloud
 Organizations may host critical applications on private
clouds.
 where as relatively less security concerns on public cloud.
 usage of both public and private together is called hybrid
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cloud.
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14. Advantages of Cloud Computing










Lower computer costs.
Improved performance.
Reduced software costs.
Instant software updates.
Improved document format compatibility.
Unlimited storage capacity.
Increased data reliability.
Universal document access
Easier group collaboration
Device independence
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15. Disadvantages of Cloud Computing

Requires a constant Internet connection:

Cloud computing is impossible if you cannot connect to
the Internet.

Since you use the Internet to connect to both your
applications and documents, if you do not have an
Internet connection you cannot access anything, even
your own documents.

A dead Internet connection means no work and in
areas where Internet connections are few or inherently
unreliable, this could be a deal-breaker.

When you are offline, cloud computing simply does not
work.
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16. IDaaS
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17. 
Multiple passwords are recipes for disaster,
Agree ?

SSO – Single Sign On
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18. 06-03-2014
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19. 06-03-2014
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20. Introductions

In cloud computing, entities may have multi accounts
associate with a single or multi service provider(SP).

Share sensitive identity information(Personal
identifiable information or PII) along with associated
attributes of the same entity across services can be
lead to mapping of the identity to the entity,
tantamount to privacy loss.
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21. IDM
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22. Introductions

Identity management(IDM) is one of the core
components in cloud privacy and security and can
help alleviate some of the problems associated with
cloud computing.

To use a cloud service, a user need to authenticate
herself/himself to it.

The user has to give away some private information,
which uniquely identifies the user to SP. That is user’s
PII(Personal identifiable information).
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23. 06-03-2014
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24. Identity Management
Architecture





Enterprise Service Bus (ESB)- 20+ IDM services
are exposed.
Authentication,
Authorization,
Password
Management, Provisioning, and Policy. (scalable
and extensible)
Process Engine- request approval, removal of
access, audit events, etc.
Ex-CRM system may publish data to a predefined email address.
Scripting -Groovy Script, integrates well with
the framework.
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25. Identity Management
Architecture
Audit and Compliance- capturing audit events
and publish them to the ESB.
 Reporting- tools to create reports and graphs.

Identity manager removes the users from the
systems that they no longer need and adds the
users to systems that do need access to.
 Similarly, if a user leaves the company, all access
would be promptly terminated.

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26. Introductions

Obtaining the user’s PII gives some assurance to SPs
about the user’s identity, which helps SP to decide
whether to permit to its service or not.

The propose of an IDM system is to decide upon
the disclosure of this information in a secure
manner.(ex-Flash)
The main problem for Bob is to
decide which portion of his PII
should he disclose, and how do
disclose it in a secure way.
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27. Related work

Different solutions use different ways of sending
user’s PII for negotiation with the SPs. The common
ways are:
◦ Use of a Trusted Third Party(TTP). The major issue
with such approach in cloud computing are:
 (a) TTP could be a cloud service, so SP could be TTP ;
therefore, TTP may not be an independent trusted
entity anymore.
 (b) Using a single TTP.
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28. Related work

Different solutions use different ways of sending
user’s PII for negotiation with the SPs. The common
ways are:
◦ Prohibiting untrusted host. A client application
holding PII must be executed on trusted host to
prevent malicious host from accessing PII.
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29. Relate works
PRIME- using TTP – IdP
 Windows CardSpace
 OpenID

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30. Windows CardSpace
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31. Select Research Problems

Authenticating without disclosing PII
◦ When a user sends PII to authenticate for a service,
the user may encrypt it. However, PII is decrypted
before an SP uses it. As soon as PII is decrypted, it
becomes prone to attacks.

Using services on untrusted host
◦ The available IDM solutions require user to execute
IDM from a trusted host. They do not recommend
using IDM on untrusted hosts, such as public host
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32. Proposed scheme

The goal in the paper is to assure that IDM does
not use TTP for verifying credentials.

This implies that IDM could use TTPs for other
purpose, such as the use of a TTP by IDM for
management of decryption key.
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33. Proposed scheme

Proposed an approach for IDM in cloud computing
that:
◦ Does not require TTPS
 This is achieved through the use of multi-party
computing, in which secret are split into shares
distributed to different hosts.
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34. Proposed scheme

Proposed an approach for IDM in cloud computing
that:
◦ Can be used for an untrusted or unknown hosts
 This is achieved though the use of the active bundle
scheme. An active bundle has a self-integrity check
mechanism, which triggers apoptosis(a complete selfdestruction) or evaporation(a partial self-destruction)
when the check fails.
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35. Proposed scheme

Proposed an approach for IDM in cloud computing
that:
◦ Uses encrypted data when negotiating the use of PII
for authentication to services in cloud computing
 This is achieved by using predicate over encrypted data.
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36. Multi-party computing

Threshold secret sharing
◦ First, a secret data item D is divided into n shares D1,
D2, …, Dn, then a threshold k is chosen, so that:
 To recover D, k or more of arbitrary Di’s are required.
 Using any k-1 or fewer Di’s leaves D completely
undetermined.
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37. Multi-party computing

A function f using secret input from all the party.
Involves n party, which calculate only partial function
output.

One of the player is selected as the dealer(DLR),
and is provide the partial function outputs to find
out the full results of function computation.

Let f be a linear function of degree n known to each
of the n party, and t be an arbitrary threshold value,
and Pi denote Party i, and xi denote the secret input
of Pi for f.
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38. Multi-party computing

Let a1, a2 , …,an be distinct non-zero elements in the
domain of f. Player Pi is assigned the point ai.

DLR will receive from the n parties the partial
outputs of f calculated by the n parties using their
respective secret inputs x1, x2,…, xn.

Each party Pi generates a polynomial hi of degree t
such that hi(0)=xi
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39. Multi-party computing

Each party Pi send to each Pj one si,j=hi(aj) of Pj’s
input.

Then, each Pi computes a portion of function f using
share si,j of the input that it has or received from
n-1 other parties.
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40. Predicate encryption scheme

Predicate encryption scheme allows evaluating
predicate with encrypted data.
◦ For example, Alice can compute the predicate using
encrypted data.
1.
2.
3.
4.
Setup
Encrypt(PK,PII)
KeyGen(PK,MSK,p)
Query(PK,CT,TKp)
PK,MSK
CT
TKP
p(PII)
◦ Alice uses a Setup algorithm scheme that generate a
public key PK and a secret key MSK.
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41. Predicate encryption scheme

Predicate encryption scheme allows evaluating
predicate with encrypted data.
◦ For example, Alice can compute the predicate using
encrypted data.
1.
2.
3.
4.
Setup
Encrypt(PK,PII)
KeyGen(PK,MSK,p)
Query(PK,CT,TKp)
PK,MSK
CT
TKP
p(PII)
◦ Alice uses PK to encrypt her PII and gets ciphertext
CT.
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42. Predicate encryption scheme

Predicate encryption scheme allows evaluating
predicate with encrypted data.
◦ For example, Alice can compute the predicate using
encrypted data.
1.
2.
3.
4.
Setup
Encrypt(PK,PII)
KeyGen(PK,MSK,p)
Query(PK,CT,TKP)
PK,MSK
CT
TKP
p(PII)
◦ Alice has the function p representing a predicate that
she wishes to evaluate for her CT.
◦ She uses the KeyGen algorithm, PK ,MSK and p to
output the token TKP.
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43. Predicate encryption scheme

Predicate encryption scheme allows evaluating
predicate with encrypted data.
◦ For example, Alice can compute the predicate using
encrypted data.
1.
2.
3.
4.
Setup
Encrypt(PK,PII)
KeyGen(PK,MSK,p)
Query(PK,CT, TKP)
PK,MSK
CT
TKP
p(PII)
◦ She gives TKP to the host that evaluates the token for
CT, and returns the result p(PII) to Alice.
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44. Proposed schemes

An owner O encrypts PII using algorithm Encrypt and
O’s public key PK. Encrypt outputs CT-the encrypted PII.

The secret key MSK is spilt between n parties.

SP transform his request for PII to a predicate
represented by function P.

SP send share of p to the n parties who hold the shares
of MSK.
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45. Proposed schemes

The n parties execute together KeyGen using PK,
MSK, and P and return TKP to SP.

SP call the algorithm Query that take as input PK,
CT, TKP and produces p(PII) which is evaluation of
the predicate.

The owner O is allow to use the service only when
the predicate evaluate to “true”.
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46. Active Bundle Scheme

Include:
◦ Identity data:
 Data used for authentication, getting service, using
service
 The data are encrypted
◦ Metadata : Describe active bundle and its privacy
policy
 (a) integrity check metadata
 (b) access control metadata
 (c) dissemination control metadata
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47. Active Bundle Scheme

Includes:
◦ Virtual machine(VM):manages and controls the
program code enclosed in a bundle.
 Enforcing bundle access control policies through
apoptosis, evaporation
 Enforcing bundle dissemination policies
 Validate bundle integrity
◦ Disclosure policy:
 A set of rule for choosing which identity data to disclose
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48. Active Bundle Scheme

Active bundle send from a source host to the
destination.

An active bundle ascertain the host’s trust level
through a TTP.

Using its disclosure policy, it decides whether the
host may be eligible to access all or part of bundle’s
data, and which portion of sensitive data can be
revealed to it.
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49. Active Bundle Scheme

The remaining data may be evaporated as specified
in the access control polies, protecting the data.

An active bundle may realize its security is about to
be compromised.
◦ It may discover that its self-integrity check fail
◦ Or the trust level of its host is to low

The active bundle may choose to apoptosize , that is
perform atomically a clean self-destruction.
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50. Active Bundle Scheme
Figure : Enabling an active bundle on destination host
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51. Advantages

No need for TTPs - data exchange between a
bundle and its host is local to the host, it
protects PII from man-in-the-middle, side
channel and collaborative attacks.

Authentication without disclosing unencrypted
data.

Protection of identity data from untrusted
hosts-data reach unintended destination or are
tampered with, they apoptosize or evaporate.
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52. Resilience to Attacks
Correlation attacks on IDM - acquires a set of
PIIs and is able to correlate it to the physical
identity.
 Amazon cloud is prone to side-channel attacks
and it would be possible to steal data, once the
malicious VM is placed on the same server as its
target.
 Approaches that do not use a TTP reduce the
risk of such attacks.

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53. Conclusions

It is very likely that user end up having multiple
identities in multiple service providers security
repositories, as well as multiple credential and
multiple access permissions for different services
provided by different SPs.

There is a strong need for an efficient and effective
privacy-preserving system that is independent of
TTPs, able to unambiguously identify users that
can be trusted.
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54. References
[1] R. Gellman (2009), “Privacy in the Clouds: Risks to Privacy and
Confidentiality from Cloud Computing”, In the Proceedings of
World Privacy Forum.
[2] Karunanithi. D, Shiyamala Devi V. P, Sambath. M (January 2013),
“User
Centric
Access
Control
in
Cloud
Using
Identity
Management” International Journal of Engineering and Innovative
Technology (IJEIT) Volume 2, Issue 7.
[3] E. Shi (Oct. 2008), “Evaluating Predicates over Encrypted Data,”
Ph.D.Thesis. Carnegie Mellon University, Pittsburgh, PA.
[4] A. Shamir (Nov. 1979), “How to Share a Secret,” Communications
of the ACM, vol. 22(11), pp. 612n613.
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55. References
[5] L. Ben Othmane, and L. Lilien (Aug 2009), “Protecting Privacy in Sensitive Data
Dissemination with Active Bundles”, Proc. 7th Annual Conference on Privacy,
Security & Trust (PST 2009), Saint John, New Brunswick, Canada.
[6] Ranchal, R., Bhargava, B. ; Othmane, L.B. ; Lilien, L. ; Anya Kim ; Myong
Kang ; Linderman, M. (2010), “Protection of Identity Information in Cloud
Computing without Trusted Third Party”, In the Proceedings of Reliable Distributed
Systems,
29th
IEEE
Symposium.
[7] S. Fischer-Hubner, and H. Hebdom, XPRIME - Privacy and Identity Management for
Europe.Onlineat: ttps://www.primeproject.eu/prime_products/reports/fmwk/ub_del
D14.1.c_ec_wp14.1 _v1_final.pdf.
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56. Thank You
Queries?..
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