Cloud computing is an internet based processing model that is an important component of next generation computing. It allows the distribution of resources on demand over the Internet. The present encryption algorithms are insufficie nt for encrypting big amounts of data due to the computation complications encountered in the existing algorithms. An effective methodology for data confidentiality and integrity in cloud systems is proposed in this study. To enhance Cloud Data Security vi a the Blockchain network, Policy Agreement with Dynamic Elliptic Curve Cryptography is proposed. The Blockchain Ledger information is used to identify users. Users' policies and files are verified, and it is reported whether or not any information has been changed, guaranteeing data integrity. Hyper Mementic Search is used in conjunction with the Block Chain network to optimize information searching and thus decrease authentication time complexity. This method, Policy Agreement with Dynamic Elliptic Curve C ryptography and Blockchain technology, improves cloud data security.