This operation is useful in a system that has multiple components with different degrees of trust. For example, consider a system that stores encrypted data in containers. Each container stores the encrypted data and an encrypted copy of the data key. One component of the system, called the control plane, creates new containers. When it creates a new container, it uses this operation (GenerateDataKeyWithoutPlaintext
) to get an encrypted data key and then stores it in the container. Later, a different component of the system, called the data plane, puts encrypted data into the containers. To do this, it passes the encrypted data key to the Decrypt operation, then uses the returned plaintext data key to encrypt data, and finally stores the encrypted data in the container. In this system, the control plane never sees the plaintext data key.