ExplanationOracle Cloud Infrastructure offers best-in-class security technology and operational processes to secure its enterprise cloud services. However, for you to securely run your workloads in Oracle Cloud Infrastructure, you must be aware of your security and compliance responsibilities. By design, Oracle provides security of cloud infrastructure and operations (cloud operator access controls, infrastructure security patching, and so on), and you are responsible for securely configuring your cloud resources. Security in the cloud is a shared responsibility between you and Oracle.
In a shared, multi-tenant compute environment, Oracle is responsible for the security of the underlying cloud infrastructure (such as data-center facilities, and hardware and software systems) and you are responsible for securing your workloads and configuring your services (such as compute, network, storage, and database) securely.
In a fully isolated, single-tenant, bare metal server with no Oracle software on it, your responsibility increases as you bring the entire software stack (operating systems and above) on which you deploy your applications.
In this environment, you are responsible for securing your workloads, and configuring your services (compute, network, storage, database) securely, and ensuring that the software components that you run on the bare metal servers are configured, deployed, and managed securely.
The responsibilities can be divided as:

Explanation/Reference: https://cloudcomputing-news.net/news/2017/apr/03/oracle-secures-iso-27001-hipaa-and-soc- certification-its-cloud-portfolio/