A senior diplomat at the European External Action Service (EEAS) is preparing a secure, high-sensitivity briefing document intended for a joint EU-Member State crisis meeting. The document contains sensitive personal data regarding third-country nationals. The diplomat must select a digital workflow that ensures both the confidentiality of the data in transit and the integrity of the document while strictly adhering to EU external action protocols. Which of the following approaches best aligns with the EEAS's mandate for secure coordination and EU digital security standards?