![]() While Cryptocat is written in Javascript (aaggh!), the application is distributed as a plugin and not dumped out to you like typical script. To ensure that your key is valid ( i.e., you’re not being tricked by a MITM attacker), Cryptocat presents users with a key fingerprint they can manually verify through a separate (voice) connection.Ĭode quality: Nadim has taken an enormous amount of crap from people over the past year or two, and the result has been a consistent and notable improvement in Cryptocat’s code quality. OTR is a well-studied protocol that does a form of dynamic key agreement, which means that two parties who have never previously spoken can quickly agree on a cryptographic key. If that’s not good enough for you: go check out this year’s pwn2own results.įor non-group messaging, Cryptocat uses a protocol known as off-the-record (OTR) and ships the encrypted data over Jabber/XMPP - using either Cryptocat’s own server, or the XMPP server of your choice. Running security-critical code in a browser is like having surgery in a hospital that doubles as a sardine cannery and sewage-treatment plant - maybe it’s fine, but you should be aware of the risk you’re taking. They do eight million things, most of which require them to process arbitrary and untrusted data. To put a finer point on it: web browsers are some of the most complex software packages you can run on a consumer device. The weakness is that it runs in a goddamn web browser. Cryptocat’s impressive user base testifies to the demand for such an application. It’s a strength because (1) just about everyone has a browser, (2) the user interface is pretty and intuitive, and (3) the installation process is trivial. Living in a browser is Cryptocat’s greatest strength and greatest weakness. What truly distinguishes Cryptocat is its platform: it’s designed to run as a plugin inside of a web browser (Safari, Chrome and Firefox). CryptocatĬryptocat is an IM application developed by Nadim Kobeissi, who - when he’s not busy being harassed by government officials - manages to put out out a very useable app. ![]() A few even point this out in their marketing material, and have included their own dishonesty into the threat model. That is, they don’t require you to trust the service. One important feature of the ‘new’ encryption apps is that they recognise this concern. ![]() In this case you’retruly dependent on their good behaviour.* This works fine if the server really is trustworthy, but it’s huge problem if the server is ever compromised - or forced to engage in Man-In-The-Middle attacks by a nosy government.Īn even worse variant of this attack comes from services that actually store your secret keys for you. Clients depend fundamentally on a central directly server to obtain their encryption keys. In this scenario - known as a Man in the Middle(MITM)attack - all the encryption in the world won’t help you.Īnd this is where most ‘end-to-end’ commercial services (like Skype and iMessage) seem to fall down. The problem here is simple: if I can compromise such a service, then I can convince you to use my encryption key instead of your intended recipient’s. The real challenge turns out to be distributing users’ encryption keyssecurely, that is, without relying on a trusted, central service. That’s because actually encrypting stuff is not the interesting part. However - and this is a critical point - ‘end-to-end encryption’ is rapidly becoming the most useless term in the security lexicon. This has even gotten Skype and Blackberry into a bit of hot water with foreign governments. In fact, these days almost everyone advertises some form of ‘ end-to-end encryption‘ for your data. First, the apps we’ll talk about here are hardly the only apps that use encryption. A couple of notes…īefore we get to the details, a few stipulations. In no particular order, these are Cryptocat, Silent Circle, RedPhone and Wickr. To take a crack at answering these questions, I’m going to look at four apps that seem to be getting a lot of press in this area. How solid are they? What makes them different/better than what came before? And most importantly: should you trust them with your life? ![]() Given what’s at stake, it seems worthwhile to sit down and look carefully at some of these new tools. At the same time, I worry that too much hype can be a bad thing - and could even get people killed. After all, I’ve spent a lot of my professional life working on crypto, and it’s nice to imagine that people are actually going to start usingit. This is exciting stuff, and I want to believe. It seems like these days I can’t eat breakfast without reading about some new encryption app that will supposedly revolutionise our communications - while making tyrannical regimes fall like cheap confetti.
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