google.protobuf.timestamp_pb2.Timestamp
Required. Input only. Immutable. The time at
which the Key Management Service will
automatically create a new version of the crypto
key and mark it as the primary.
rotation_period
google.protobuf.duration_pb2.Duration
Required. Input only. Immutable. [next_rotation_time] will
be advanced by this period when the Key Management Service
automatically rotates a key. Must be at least 24 hours and
at most 876,000 hours.