We'd like to store sensitive health data using Google Cloud Storage. [Customer-Supplied Encryption Keys](https://cloud.google.com/storage/docs/using-encryption-keys) seem to provide a solution to securely store data in the cloud so that only we, the customer, might decrypt and read it. We would like to know more about this:

Are there any chances or possibilities that Google, the US Government or someone else could gain access to the decrypted sensitive data by legal means? For instance, can the GCP operators be forced somehow to extract the CSEK during runtime and use it to decrypt the storage data and/or share it with a third party? How are Law Enforcement Requests dealt concerning CSEK-encrypted data on the GCP?