Leveraging security as a service for cloud-based file sharing

A method of leveraging security-as-a-service for cloud-based file sharing includes receiving, at a cloud-based file sharing server external to an enterprise network and having connectivity to the enterprise network, instructions from an enterprise network to validate a file uploaded by a first user associated with the enterprise network before allowing the file to be downloaded. The file sharing server may then receive the file from the first user and forward the file to a cloud-based security-as-a-service (SECaaS) server that is also external to the enterprise network and has connectivity to the enterprise network. The file sharing server receives a determination of validation from the cloud-based SECaaS server and allows a second user to download the file based on the determination. To make the determination, the SECaaS server retrieves cryptographic keying material from a cloud-based key management server, and decrypts the file.