You are an agent of the EU External Action Service (EEAS) responsible for managing a high-profile digital communication campaign. You must choose the most appropriate software spreadsheet tool for processing, classifying, and visualizing large volumes of real-time data on humanitarian aid operations, ensuring that the data remains confidential and accessible only to authorized personnel. According to digital security principles and efficient tool use in institutional environments, what is the best practice for ensuring the integrity and controlled access to these sensitive data?