sftp-server file encryption

Peter Stuge
Thu, 13 Sep 2018 19:15:26 -0000

J?rgen Weber wrote:
> I wonder if sftp-server could encrypt files before writing to disc.
> This would make sshd a poor man's alternative for an encrypting
> filesystem on a server.

What does the poor man want to gain with this encryption?


> How to get the crypto key from a client to be used by sftp-server?
> Upload the key to a /well/defined/key.pem virtual location?

That can be implemented, but I don't know that it's a good idea. If
the poor man controls the server to implement something like that, then
the poor man can probably also just enable full disk crypto.


> Or can you access the ssh client certificate from sftp-server?

SSH clients don't always use a certificate, nor always a key.


> Can sftp-server call a filter?

No, but you can post-process uploaded files as the filesystem changes.

> Or would one write a sftp-server replacement?

You can, but the poor man needs root access to deploy that, and if he
is root then he's probably better off with full disk crypto.


//Peter