[heresie-dabord]

I agree with the parent.

E-mail is grotesquely expensive to manage because of its weaknesses and its use as a vector of attack.

The best replacement solution is an organisational portal that people use to communicate with the organisation and upload/download documents. Some governments and banks have already been handling interactions with external entities and citizens/customers this way for years.

The upload and download tunnel is secure, the receiver can scan the uploaded information (detonate in a sandbox if necessary), and the sender can trust the messages and documents that are downloaded.