[liberationtech] PGP is hard to use and needs stuff installed on your computer. Use PassLok instead.

Julian Oliver julian at julianoliver.com
Sat Jul 27 06:07:13 PDT 2013


..on Fri, Jul 26, 2013 at 03:42:02PM -0500, Francisco Ruiz wrote:
> Scenario: you, Alice, realize you're under NSA surveillance. You need to
> get a crucial bit of information to your friend Bob, right away.
> You've been using PGP, but now you suspect the NSA may have installed a bug
> on your machine. Your keystrokes are being recorded.
> 
> What can you do? Use PassLok instead.
> 
> I wrote PassLok with three guiding principles in mind:
> 1. Absolutely nothing should be installed or even written in the computer.
> Alice should be able to go to the local library or borrow someone else's
> smartphone, and leave no traces behind.
> 2. Best security available. No compromises.
> 3. Graphical interface. Only one screen, as clean as possible.
> 
> Therefore, PassLok is written entirely in javascript. Once you load the
> page at https://passlok.site44.com (http://passlok.com redirects you
> there), you can save the file and you have PassLok even offline. You can
> view the source and convince yourself that it is not connecting with any
> server. If you know some cryptography, you can see that it is using the
> well-known SJCL routines for AES encryption/decryption and elliptic curve
> functions. Since the elliptic curves implemented in the current version of
> SJCL only go up to the 384-bit NIST curve, I added the 521-bit NIST curve
> (equivalent to a 15000-bit RSA key in predicted security) so that PassLok
> uses that as a default. Even at 521 bits, the public keys are small, as you
> can see from my lock (public key) below.
> 
> PassLok performs public-key cryptography using the Diffie-Hellman key
> exchange rather than RSA, so you can use whatever secret key you want.
> Hopefully something that is both very hard to guess and easy to remember,
> so you never have to write it down. PassLok will help you to come up with a
> strong key, but won't force you in any way.
> 
> PassLok can sign and verify signatures, too (many PGP implementations, such
> as Mailvelope, cannot), and can also include a second secret message under
> a separate key, to beat the "rubberhose attack." If you are not sure about
> the authenticity of something, PassLock can make a short ID that you can
> read over the phone. All of it from a single screen.
> 
> I want people to use PassLok and uncover any bugs it might still have,
> before I move on to a Gmail plugin based on its engine. I believe it is
> already very secure and easy to use by those who know a little
> cryptography. Hopefully the metaphor used throughout PassLok, about locks
> and keys rather than private/public key pairs, will also make it usable by
> novices.
> 
> I'll appreciate any feedback you can give me. The link is repeated at the
> bottom.

I haven't given it an audit but so far it appears to be a very nice
implementation. Congratulations. And yes, it passed the offline, locally hosted
test ;)

I feel clicking on the title 'Key / Lock Conbination' for instructions would
baffle most people. The 'step by step instructions' page is good, but I think it
could be more helpfully integrated. Perhaps you could have a drop-down menu for
each use case, with instructions appearing as hints in each field.

Again, great work and a great contribution!

Cheers,

-- 
Julian Oliver
PGP B6E9FD9A
http://julianoliver.com
http://criticalengineering.org



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