With the advances in technology and the abundance of information, cloud computing services have become indispensable because they enable the backup and availability of data, which implies access anytime and from anywhere. The collective use of cloud data poses an important issue in the security field, mainly in encryption to exchange or store data. Nowadays, cloud computing offers a suitable platform for users to exploit data. Nevertheless, the cloud can be an untrusted party exposing the decrypted data to misuse. Cryptography helps solve many computing problems, including securing the communication of cloud entities. For this reason, researchers are constantly working to find solutions to various challenges to preserve data and systems. Homomorphic encryption is an aspect of autonomy that enables secure use of the cloud. This work proposes powerful and efficient solutions represented by homomorphic encryption techniques. In addition, homomorphic encryption cannot answer other questions for cloud entities. Cloud computing suffers from other issues such as lack of transparency, trust, and centralization of control. Blockchain has powerful features like decentralization that allow it to add enhancements to cloud computing, including autonomy, security, reliability, and transparency. Therefore, we propose a few consensus algorithms which are the hearts of the secure blockchain.