To ensure the security of confidential information for builds in Cloud Build, what is a recommended practice?

The recommended practice for ensuring the security of confidential information during builds in Cloud Build is to create an entry in Secret Manager, specify the URI for the confidential secrets in the Cloud Build configuration file, and reference the secrets as parameters in the build steps. This approach takes advantage of Google Cloud's Secret Manager, which is specifically designed for securely storing and managing sensitive data such as API keys, passwords, and other secrets.

By storing confidential information in Secret Manager, you benefit from built-in encryption, access controls, and auditing features. This allows you to manage permissions more effectively, ensuring that only authorized build processes have access to sensitive information. Referencing the secrets in the Cloud Build file helps to keep them out of the source code and allows for dynamic retrieval at build time, without hardcoding sensitive data in repositories.

The other options do not provide the same level of security. For instance, triggering builds from the command line with parameters can expose sensitive data to logs or command history, creating a security risk. Similarly, storing encrypted files in a repository does not eliminate the vulnerability of accessing the repository itself, and managing sensitive information separately in a new repository can lead to operational complexity and increase the risk of accidental exposure. Thus, employing Secret Manager is the most secure and efficient