Abstract: In recent days, big data is one of the widely used technology in many cloud based applications. So, providing security and ensuring privacy for the data that stored in cloud is an essential task due to the distributed storage. For this purpose, different security mechanisms based on encryption and decryption are developed in the traditional works. But it mainly lacks with some major limitations such as increased computational complexity, reduced security and high overhead. Thus, this research aims to develop a new mechanism for providing security to the big data that stored in cloud. At first, the data owner selects their data and generating the corresponding base point to the data based on the elliptic curve. Then, the corresponding key is generated for the data by implementing an Elliptic Curve Diffie Hellman (ECDH) algorithm. Further, it is encrypted with the use of Elliptic Curve Cryptography (ECC) based encryption technique. After that, the encrypted data is send to the Cloud Service Provider (CSP) and its corresponding signature is generated at the data owner side and is forwarded it to the Third Party Auditor (TPA). When, the data user sends the request to the CSP which sends the encrypted data and the TPA sends the generated signature to the data user. After that, the Message Authentication Code (MAC) generation and verification processes are performed at the data user side. If the generated signature and the received signature are same, the data is decrypted by the data user. During experimentation, the performance results of existing and proposed security mechanisms are validated based on different measures for proving the superiority of the proposed ECDH-ECC technique.