[tahoe-dev] help—how do we communicate the difference between using someone else's gateway and using your own?

Zooko O'Whielacronx zooko at zooko.com
Thu Aug 25 12:07:40 UTC 2011


This issue has been bothering me for a while, and it just came up
again in the context of #1425 (blacklist support):


    When releasing 1.9, we should go to extra effort to communicate
what this change does and doesn't do. I've been learning that almost
all users have very simpleminded models of things, for example I think
the existence of the public web gateway made most users think that
Tahoe-LAFS was nothing more than some sort of online service.
Explaining this feature (in the NEWS/release-notes/etc.) may be a good
opportunity to explain the difference between running your own
software (Tahoe-LAFS storage client) to upload or download files vs.
visiting a web server (Tahoe-LAFS gateway) operated by someone else
and asking them to serve files to you.

    This feature lets the operator of a Tahoe-LAFS storage client (==
Tahoe-LAFS gateway == the web server in question) configure their
software so it refuses to serve certain files (to anyone). It does not
give them any ability to affect whether other Tahoe-LAFS storage
clients/gateways access those files.

    How can we make this clear? Maybe the only way to make this clear
is to create a variant of
http://tahoe-lafs.org/~zooko/network-and-reliance-topology.png which
shows multiple gateways in use, and indicate on that diagram that the
blacklisting feature affects only the single gateway that chooses to
use it.

The way this sort of thing has come up before is the way that a lot of
people seemed to think that the publicly accessible demo gateway *was*
Tahoe-LAFS, or that it somehow added Tahoe-LAFS's security properties
to your data when you used it as a public pastebin. We tried to
disabuse them of that mistake, first by changing the URL from
"pubgrid.tahoe-lafs.org" to "insecure.tahoe-lafs.org", and then by
adding a prominent warning (in Mandarin Chinese) on the front page,
and then we eventually just took down the public demo gateway

This is actually pretty important because all of Tahoe-LAFS's unique
security properties obtain *only* when you operate your own gateway.
If you run your own gateway then rely *only* on your own computer for
the confidentiality and integrity of the files. That fact is what is
new and cool about Tahoe-LAFS!

If you use someone else's gateway, then you simply rely on *that
computer* for those properties, which means you would be vulnerable to
anyone who controls that computer (including its owner and any
attacker who can take over control of it). That gives you no
particular security properties. From your perspective, whether the
host is running Tahoe-LAFS to serve those files to you from a storage
grid or whether they are running Apache to serve those files to you
from their hard disk makes no difference [*].

What do you think? Did you used to confuse these two concepts in your
mind, and if so, what clarified it for you? Can you think of a way to
explain the difference between these two deployment modes?

I've (perhaps somewhat cynically) started to think that people can
only keep one thing in their minds at a time. Maybe we need to stop
telling newcomers about the concept of "letting other people use your
gateway", and instead just tell them that the way to use Tahoe-LAFS is
to run your own gateway on your local computer and then use it



[*] There is actually a difference, which is that the capabilities are
visible in the URLs so you could in theory set up your own gateway and
then use it to download the same file and *double-check* whether they
had violated integrity by unauthorizedly modifying the file they had
earlier served to you. However, as long as you don't do that, then
there is no difference between using a Tahoe-LAFS gateway and using an
apache web server.

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