Tardigate client side

If whatch this all on client side, what about security. All speaking that it is very secure.
But what to do if private key was compromised, then i cant just turn it of like my NAS than data leack or deletion not hapen. Same is if this will be mount like web HDD, is there some oditional switch or something to protect data, because whu has private key role this data. if clien have encryption virus, all data will be encrypted. As i remember as data is already encrypted, you cant just change it, you need to download it and change and upload new one back. This is the question is there some posibilities, like dropbox, hold old data for 30 days like, you have backup.