This document summarizes a seminar presentation on an efficient certificate-less encryption for secure data sharing in public clouds. The presentation covers the introduction to cloud computing and encryption/decryption techniques. It discusses the scope of applying mediated certificate-less public key encryption to solve key escrow and revocation problems. The objective is to design an attribute-based encryption scheme that allows encrypted data access based on access policies. The presentation reviews existing algorithms and proposes a pairing-free certificate-less public key cryptography approach. It describes the system architecture and implementation details. The results show the proposed scheme improves efficiency and provides confidentiality of data and keys when using untrusted public clouds.

1. A Seminar Presentation
On
An Efficient Certificate-less Encryption
for
Secure Data Sharing in Public Clouds
Seminar by :-
Abhijeet S. Patil

2. Contents
 Introduction
 Scope
 Objective
 Literature Review and Proposed system
 Motivational Outcome
 System Architecture
 Implementation Details
 Existing Algorithm
 Selected Algorithm
 Application and Results
 Conclusion
 References

3. Introduction

4. Cloud Computing
• Cloud Computing is the delivery of
computing services over the Internet.
• Types of Cloud Computing
• Private Cloud
• Public Cloud
• Hybrid Cloud
• Community Cloud
• Organizations have been adopting public
cloud services such as Microsoft Skydrive,
Dropbox, Google Drive to manage their
data with the help of Cloud Computing

5. Encryption and Decryption
• Encryption
• The data owner obtains the key of
users from the cloud. Then data
owner encrypts the data using the
public key of user.
• Types of Encryption
Symmetric Key Encryption
Public key Encryption
• Decryption
• When a user wants to read some data,
it sends a request to the Sender to
obtain the partially decrypted data.
• With the help of private key he
decrypts the data and access it.

6. Scope of Proposed System
 Mediated certificateless public key encryption (mCL-PKE) solves the key escrow problem
in identity based encryption and certificate revocation problem in public key
cryptography.
 Since most CL-PKC schemes are based on bilinear pairings, they are computationally
expensive.
 Our scheme reduces the computational overhead by using a pairing-free approach.
 Compared to symmetric key based mechanisms, our approach can efficiently manage keys
and user revocations.

7. Objective of Seminar
 Existing Machine Objective :-
 Existing mCL-PKE schemes are either inefficient because of the use of expensive
pairing operations or vulnerable against partial decryption attacks.
 Seminar Objective & Scope :-
 Attribute Based Encryption(ABE) has been proposed that allows one to encrypt
each data item based on the access control policy applicable to the data.

8. Literature Review
and
Proposed system

9. Motivational Outcome
 Implementation of a mCL-PKE scheme and evaluation of its security to provide a
confidentiality of the data stored in an untrusted cloud improve the efficiency of
encryption at the data owner.
 The confidentiality of the content and the keys is preserved with respect to the
cloud, because the cloud cannot fully decrypt the information results show that
our schemes are efficient and practical

10. System Architecture

11. Implementation Details

12. Existing Algorithm
 Certificateless public key cryptography (CL-PKC)
 Ciphertext-Policy Attribute-Based Encryption
 Relations Among Notions of Security for Public-Key Encryption Schemes
 RSA trapdoor Encryption
 Fuzzy Identity-Based Encryption
 A Certificateless Proxy Re-Encryption Scheme for Cloud-based Data Sharing

13. Selected Algorithm
 SetUp
 SetPrivateKey
 SetPublicKey
 Encrypt
 USER-Decrypt

14. Implementation Details

15. Applications and Results
 mCL-PKE scheme is applied to construct a practical solution to the problem of sharing
sensitive information in public clouds.
 The confidentiality of the content and the keys is preserved with respect to the
cloud.
 Result shows that the scheme system implemented is effective, efficient and
practical.
 Data retrieval, Data encryption and Data decryption strategy

16. Conclusion
In this seminar, it is proposed the first CL-PKE scheme without pairing operations and provided
its formal security. So, here In public key systems supporting queries on encrypted data a
secret key can produce tokens for testing any supported query predicate. We presented a
general framework for analyzing security of searching on encrypted data systems. The mCL-
PKE solves the key escrow problem and revocation problem

17. Thank you…!!!!!!