Before transmitting sensitive financial data to the cloud, the best defense against interception threats like packet capture and man-in-the-middle attacks is encryption. Encryption protects data in transit by converting plain text into cipher text, which can only be deciphered with the correct keys.
Hashing provides integrity verification but does not secure confidentiality. Change tracking monitors modifications but does not prevent interception. Metadata labeling adds context but does not protect against on-path attackers.
Using strong encryption protocols (e.g., TLS) ensures that even if traffic is intercepted, the attacker cannot read the data. Encryption also aligns with compliance requirements such as PCI DSS, which mandates encryption for financial data during transmission. By encrypting before upload, the user ensures end-to-end confidentiality across potentially insecure networks.