Encrypts data using a key.
This method encrypts data using the key specified by KeyName and (for asymmetric keys) VersionId.
For symmetric keys, VersionId must be empty; the server always uses the primary version of the symmetric key. (Unless the ForceSymmetricEncryption configuration setting is enabled, in which case VersionId can be used to specify a non-primary version.)
For asymmetric keys, VersionId must be specified. Note, however, that Google does not support server-side asymmetric encryption (only decryption), so this method will instead call GetPublicKey internally and then use the public key to encrypt the input data locally. This functionality is offered as a convenience.