webwormhole

README

THIS PROJECT IS STILL IN EARLY DEVELOPMENT IT USES EXPERIMENTAL
CRYPTOGRAPHIC LIBRARIES AND IT HAS NOT HAD ANY KIND OF SECURITY
OR CRYPTOGRAPHY REVIEW THIS SOFTWARE MIGHT BE BROKEN AND UNSAFE

	https://xkcd.com/949/

WebWormhole creates ephemeral pipes between computers to send files
or other data. Try it at https://webwormhole.io or on the command
line.

On one computer the tool generates a one-time code:

	$ cat hello.txt
	hello, world
	$ ww send hello.txt
	east-pep-aloe

On another use the code to establish a connection:

	$ ww receive east-pep-aloe
	$ cat hello.txt
	hello, world

To install the command line tool:

	$ go install webwormhole.io/cmd/ww@latest

This requires Go 1.13 or newer.

To run the signalling server you need to compile the WebAssembly
files first.

	$ make wasm
	$ ww server -https= -http=localhost:8000

To package the browser extension for Firefox or Chrome:

	$ make webwormhole-ext.zip

To run the server using docker:
	$ docker build -t webwormhole .
	$ docker run -p 8000:80 webwormhole

To use a custom signalling server.
	$ ww -signal http://localhost:8000 send test.txt
	east-pep-aloe
	$ ww -signal http://localhost:8000 receive east-pep-aloe

WebWormhole is inspired by and uses a model very similar to that
of Magic Wormhole.

	https://github.com/warner/magic-wormhole

It differs in that it uses WebRTC to make its connections. This
allows us to make use of WebRTC's NAT traversal tricks, as well as
the fact that it can be used in browsers. The exchange of session
descriptions (offers and answers) is protected by PAKE (we use
CPace) and a generated random password, similar to Magic Wormhole.
The session descriptions include the fingerprints of the DTLS
certificates that WebRTC uses to secure its communications.

The author operates the signalling server at webwormhole.io, its
alias wrmhl.link, and a relay server. These are free to use but
come with no SLAs or any guarantees of uptime. They facilitate
establishing connections between peers, but do not handle any
transferred data in cleartext.

The protocol does not need to trust the signalling server to maintain
the confidentiality of the files transferred. However, the convenience
of using the web client directly on webwormhole.io comes at the
cost of having to trust the code it serves. If the server is ever
compromised it can be used inject malicious code that undermines
the security of the client. To mitigate this, you can have more
control over which version of the client you run by using the command
line client or the browser extension. The extension is identical
to the web client, but packaged for Chrome and Firefox, loads no
remote code, and requires no permissions:

	https://addons.mozilla.org/firefox/addon/webwormhole/
	https://chrome.google.com/webstore/detail/jhombkhjanncdalcbcahinpjoacaiidn

Unless otherwise noted, the source files in this repository are
distributed under the BSD-style license found in the LICENSE file.

Frequently asked questions

Is it compatible with magic-wormhole?

	It is not. Maybe one day.

	This project started as a UI for magic-wormhole, but drifted
	away when I wanted to experiment with the PAKE used, the
	protocol, and the word lists.

Why CPace and not another PAKE algorithm?

	CPace and PAKE2 were the finalists for CFRG PAKE selection
	process (https://github.com/cfrg/pake-selection), so it was
	going to be one of the two.

	CPace (https://tools.ietf.org/id/draft-haase-cpace-01.html)
	looked nice and simple to implement, and there wasn't a
	CPace Go package at the time, so it was a good opportunity
	and a learning exercise to write one. I ended up nerd-sniping
	Filippo instead and he beat me to write filippo.io/cpace.

Why not the PGP word list?

	The PGP word list (https://en.wikipedia.org/wiki/PGP_word_list)
	is quite good as far as unambiguity goes. However, a few
	word combinations do make some unsavoury phrases. I switched
	to a word list that is more agreeable.

	Also, it would be nice to experiment with localised word
	lists.

Don't you have to trust the web server anyway? What's the point of
the PAKE?

	Yes and no. The application itself, because of the PAKE,
	does not need to trust the signalling server. You can install
	the command line tool, the browser extension, or host the
	web application's files yourself and not have to trust the
	signalling server at all. There's also a mobile app version
	in the works.

	The web version hosted on webwormhole.io exists as a middle
	ground between convenience and security. Like any other
	website you visit, you do have to trust it's not running
	any malicious code in your browser.