Why can't I connect my Koofr account to providers that have client-side encryption?

Mega, Tresorit and others are client-side encrypted services. To add any of them to our service and have them work the same as other clouds, would mean we would have to keep users passwords for those services on our servers and decrypt the files. We do not want to keep such things in our databases, as they are private passwords and should only be kept by the users. This is why we have not and will not be adding client-side encrypted services to Koofr.