A bastion is a system that is exposed to the public Internet to perform a specific function, but it is highly restricted and secured to just that function. Any nonessential services and access are removed from the bastion so that security countermeasures and monitoring can be focused just on the bastion's specific duties. A honeypot is a system designed to look like a production system to entice attackers, but it does not contain any real data. It is used for learning about types of attacks and enabling countermeasures for them. A firewall is used within a network to limit access between IP addresses and ports. A proxy server provides additional security to and rulesets for network traffic that is allowed to pass through it to a service destination.

ISO/IEC 27018 was implemented to address the protection of personal and sensitive information within a cloud environment. ISO/IEC 27001 and its later 27001:2015 revision are both general- purpose data security standards. ISO/IEC 19889 is an erroneous answer.

Portability is the ability for a cloud customer to easily move their systems, services, and applications among different cloud providers. By avoiding reliance on proprietary APIs and other vendor-specific cloud features, an organization can maintain flexibility to move among the various cloud providers with greater ease.
Reversibility refers to the ability for a cloud customer to quickly and easy remove all their services and data from a cloud provider. Interoperability is the ability to reuse services and components for other applications and uses. Scalability refers to the ability of a cloud environment to add or remove resources to meet current demands.