BLOCK CHAIN BASED SECURED DATA SHARING SYSTEM FOR CLOUD ENVIRONMENT

Abstract

Cloud Storage has become the most preferred storage system for data and file storage since it can be accessed from anywhere across the internet. Even though it has its own perks and advantages, there are some flaws in the storage systems in its security. Cloud security for cloud storage system has intense security mechanism but it does not mean that the security system can be broken. To make sure that does not happen a Multi-user system for access control of datasets stored in an untrusted cloud environment is used. Like any other untrusted environment Cloud storage needs the ability to secure shared information. This approach which proposed provides an access control over the data stored in the cloud without the provider participation. The main tool of access control mechanism is cipher text-policy attribute-based encryption scheme with dynamic attributes. In the proposed system a block chain based decentralized ledger is used. This system also provides immutable log of all meaningful security events, such as key generation, access policy assignment, change or revocation, access request. A set of cryptographic protocols is proposed which ensures privacy of cryptographic operations requiring secret or private keys. Only cipher texts of hash codes are transferred through the block chain ledger. This means that the every events which occurs gets stored in the ledger which gives us the access to know the events which has happened in the storage system, which improves the system, and also the system generates key to the ones who wants to access the data or files in the storage system. This enables a more secure cloud environment where the breaking of the security system is more complicated. Thus this system provides a more secure data sharing system for cloud environment.