Effortless password protected sharing of files via Freenet

TL;DR: Inserting a file into Freenet using the key KSK@<password> creates an invisible, password protected file which is available over Freenet.

Often you want to exchange some content only with people who know a given password and make it accessible to everyone in your little group but invisible to the outside world.

Until yesterday I thought that problem slightly complex, because everyone in your group needs a given encryption program, and you need a way to share the file without exposing the fact that you are sharing it.

Then I learned two handy facts about Freenet:

• Content is invisible to all but those with the key
  <ArneBab> evanbd: If I insert a tiny file without telling anyone the key, can they get the content in some way?
  <evanbd> ArneBab: No.

• You generate a key from a password by using a KSK-key
  <toad_> dogon: KSK@<any string of text> -> generate an SSK private key from the hash of the text
  <toad_> dogon: if you know the string, you can both insert and retrieve it

In other words:

Just inserting a file into Freenet using the key KSK@<password> creates an invisible, password protected file which is shared over Freenet.

The file is readable and writeable by everyone who knows the password (within limits¹), but invisible to everyone else.

To upload a file as KSK, just go to the filesharing tab, click “upload a file”, switch to advanced mode and enter the KSK key.

Or simply click here (requires freenet to be running on your computer with default settings).

It’s strange to think that I only learned this after more than 7 years of using Freenet. How many more nuggets might be hidden there, just waiting for someone to find them and document them in a style which normal users understand?

Freenet is a distributed datastore which can find and transfer data efficiently on restricted routes (search for meshnet scaling to see why that type of routing is really hard), and it uses a WebOfTrust for real-life spam-resistance without the need for a central authority (look at your mailbox to see how hard that is, even with big money).

How many more complex problems might it already have solved as byproduct of the search for censorship resistance?

So, what’s still to be said? Well, if Freenet sounds interesting: Join in!