International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 04 | Apr -2017
p-ISSN: 2395-0072
www.irjet.net
Ciphertext Policy Attribute Based Encryption Sneha Chandrashekhar Parit1, Dr. Rashmi Rachh2 1Assistant 2Associate
professor VCET Puttur professor VTU,Belagavi
---------------------------------------------------------------------***--------------------------------------------------------------------Abstract - – The cloud computing has fundamentally changed the landscape of computers, storage and services. But the main hindrance to its adaptation is security. In literature, various counter measures are used to address this issue. One of them being attribute based encryption for “fine grained access control”. In this project, “ciphertext policy attribute based encryption” scheme is used for providing cloud security and fine grained access control which allows encrypting data based on set of attributes called policy. Attributes are selected by owner who uploads file. Owner will choose the eligible users to access information. The cipher text produced will be accessible only if the policy is satisfied.
Elliptic curve has been used in CPABE scheme. The main advantage of using this scheme is its key size and faster speed [3]. Elliptic curves uses smaller key sizes compared to other methods. Some of the crypto systems like AES,DES are said to be secure but they require their key to be distributed among number of users which may cause unauthorized people to get the information. That problem has been overcome in CPABE. It does not require a key to be distributed for encryption and decryption. Each user will have their own unique keys generated. Each keys are generated by using the attributes given by users.
Key Words: policy, fine grained access control, attribute based encryption.
CPABE scheme requires attributes for encryption[10]. This can be represented by the tree structure. There are number of levels in the tree. The top most root in the tree is called root node lower level nodes are leaf nodes. Threshold value has been set that can be any value in between. This has to be satisfied for example having 3 attributes or nodes among them all 3 should be satisfied. Given as “3of3” is also called as policy.
B. Access tree structure
1.INTRODUCTION Due to emerging technologies day today life has become faster. Now a day people want to store their data on cloud. Cloud is an Internet storage area where users can use storage efficiently and the services of cloud without having to worry about how they work. We can say that cloud is an abstraction for internet. Now a day attribute based encryption has paid a lot of attention. The main goal was to provide security and access control.In this scheme it allows encryption and decryption of data that depends on attributes of users. Policy has been defined here associated with access tree structure. The ciphertext produced will be accessible by user only if the policy is satisfied[12].
C. Elliptic curve cryptography In a cryptosystem we know that securing data has a major role.[3] Consider Alice and Bob both want to share their data securely. There may be a problem of EVE who can trap that information so Alice gets the public key of Bob encrypts the message and sends him. This key will be available to everyone but only Bob can decrypt it because only he is having private key to decrypt. At the same time they can add their signature and send that information. For example Alice sends message encrypting it with her signature when Bob gets that message he checks whether this message has sent from Alice or not if yes then he gets that authentic message. If that message is used by an eavesdropper then he gets garbage then Bob will get to know that message has been eavesdropped. Similarly for providing more security we use this elliptic curve which makes difficult to get that public and private keys.
A. Cipher text policy attribute based encryption The new technique of encryption and decryption method is CP-ABE where users without fear can store their information in any servers. This is an improvement of identity based encryption. Provides faster and secure access of data by restricting access to specified users[1,2]. This scheme considers attributes or credentials that describe users. Using those attributes files will be encrypted. This indicates the owner who is uploading files is going to select recipients, only those can access information.
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