[liberationtech] Crypho

[Yiorgis Gozadinos]

On Mar 24, 2013, at 01:11 , Steve Weis <steveweis at gmail.com> wrote:

> Hi Yiorgis. The Crypho web page says:
> "No-one can access your data, either in transit or when stored — Not even Crypho staff or the government."
> 
> Yet, you acknowledge that "we are aware of the potential problems of serving JS [Javascript]", meaning it's trivial for your staff or a government to compromise the Javascript code and cause it to leak plaintext data. 
> 
> Even the authors of the Stanford Javascript Crypto Library (SJCL), which Crypho "uses solely", say that it's not feasible to secure:
> "Unfortunately, [SJCL] is not as great as in desktop applications because it is not feasible to completely protect against code injection, malicious servers and side-channel attacks." (http://crypto.stanford.edu/sjcl/)

Hey Steve,

Thanks for bringing this up. We are aware of the js crypto controversy and it is a challenge for us as we are trying to make crypto more approachable.

On the technical side, like I said, we will try to address the issue of trusted js by implementing apps as well as explore ways of asserting the authenticity of served js. Open-sourcing the client code will certainly help in auditing. There are other things we put in place to help, CSP, Strict-Transport-Security and X-Frame-Options headers for example or a proper SSL setup.
These cannot guarantee of course that we haven't overseen things, but our hope is that gradually we can build trust on our app.

Now, similar issues exist of course on networked desktop apps just as well. Nobody can guarantee that malware will not eavesdrop on you, and it is pretty hard to assert there are no backdoors in proprietary software.

The argument, when stretched, eventually leads to: Unless you are a skilled cryptographer, and can audit/inspect/write your own code, you should not be using crypto because it is dangerous and you will invariably screw up somewhere. While this is true in a few cases, and it should not be taken lightly, it leaves something to be desired for the rest of us.

In my professional life, I have yet to see somebody who is not a geek, or has received training, use PGP or encrypt data strongly. The process is complex, and it is easier to screw up than use properly. In addition to that, "normal" people when faced with the choice between security and convenience, will invariably pick the second.

Businesses start recognising that they over-share, and some even become reluctant to use cloud services, because of various reasons, be it policy, fear or cross-border legislation. What we try to do, is bridge the gap, and provide a familiar and convenient interface sacrificing in the way as little security as possible.

Again, that does not make Crypho the tool of choice if you are an activist, risking your life. Between the activist and John Doe the lawyer who wants to share a contract with his client without storing it plain in the US, there is a big gap. We hope that Crypho will cater well for the second case.

-- 
Yiorgis Gozadinos
www.crypho.com