A company backs up customer data to an external cloud storage provider. Which security measure ensures the data remains confidential even if the provider is compromised?

A firewall acts as a barrier between an internal network and external threats, monitoring and controlling incoming and outgoing traffic. While it enhances network security by blocking unauthorized access, it does not protect the confidentiality of data stored in the cloud itself. If the cloud provider is compromised, a firewall cannot prevent unauthorized access to the data.

A VPN (Virtual Private Network) creates a secure tunnel for data transmission over the internet, protecting the data in transit from eavesdroppers. However, once the data reaches the cloud storage provider, it remains unprotected if not encrypted. If the provider is compromised, the data could still be accessed in its original form.

A web filter is designed to block access to specific websites and content based on predefined criteria, thereby preventing users from accessing harmful or unwanted material. While it can enhance security by restricting access, it does not protect stored data from being accessed if the cloud provider is compromised.