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	<title>Benlog &#187; privacy</title>
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	<link>http://benlog.com</link>
	<description>security, privacy, transparency.</description>
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		<title>encryption is (mostly) not magic</title>
		<link>http://benlog.com/articles/2011/12/21/encryption-is-mostly-not-magic/</link>
		<comments>http://benlog.com/articles/2011/12/21/encryption-is-mostly-not-magic/#comments</comments>
		<pubDate>Wed, 21 Dec 2011 20:17:08 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[crypto]]></category>
		<category><![CDATA[mozilla]]></category>
		<category><![CDATA[privacy]]></category>
		<category><![CDATA[security]]></category>
		<category><![CDATA[web]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1878</guid>
		<description><![CDATA[A few months ago, Sony&#8217;s Playstation Network got hacked. Millions of accounts were breached, leaking physical addresses and passwords. Sony admitted that their data was &#8220;not encrypted.&#8221; Around the same time, researchers discovered that Dropbox stores user files &#8220;unencrypted.&#8221; Dozens (hundreds?) closed their accounts in protest. They&#8217;re my confidential files, they cried, why couldn&#8217;t you [...]]]></description>
			<content:encoded><![CDATA[<p>A few months ago, <a href="http://en.wikipedia.org/wiki/PlayStation_Network_outage">Sony&#8217;s Playstation Network got hacked</a>. Millions of accounts were breached, leaking physical addresses and passwords. Sony admitted that their data was &#8220;not encrypted.&#8221;</p>
<p>Around the same time, researchers discovered that <a href="http://en.wikipedia.org/wiki/Dropbox_%28service%29#Criticism">Dropbox stores user files &#8220;unencrypted.&#8221;</a> Dozens (hundreds?) closed their accounts in protest. They&#8217;re my confidential files, they cried, why couldn&#8217;t you at least encrypt them?</p>
<p>Many, including some quite tech-savvy folks, were quick to indicate that it would have been so easy to encrypt the data. Not encrypting the data proved Sony and Dropbox&#8217;s incompetence, they said.</p>
<p>In my opinion, it&#8217;s not quite that simple.</p>
<p>Encryption is easy, it&#8217;s true. You can download code that implements military-grade encryption in any programming language in a matter of seconds. So why can&#8217;t companies just encrypt the data they host and protect us from hackers?</p>
<p>The core problem is that, to be consumable by human users, data has to be decrypted. So the decryption key has to live somewhere between the data-store and the user&#8217;s eyeballs. For security purposes, you&#8217;d like the decryption key to be very far from the data-store and very close to the user&#8217;s eyeballs. Heck you&#8217;d like the decryption key to be *inside* the user&#8217;s brain. That&#8217;s not (yet) possible. And, in fact, in most cases, it isn&#8217;t even practical to have the key all that far from the data-store.</p>
<h4>encryption relocates the problem</h4>
<p>Sony needs to be able to charge your credit card, which requires your billing address. They probably need to do that whether or not you&#8217;re online, since you&#8217;re not likely to appreciate being involved in your monthly renewal, each and every month. So, even if they encrypt your credit card number and address, they also need to store the decryption key somewhere on their servers. And since they probably want to serve you an &#8220;update your account&#8221; page with address pre-filled, that decryption key has to be available to decrypt the data as soon as you click &#8220;update my account.&#8221; So, if Sony&#8217;s web servers need to be able to decrypt your data, and hackers break into Sony&#8217;s servers, there&#8217;s only so much protection encryption provides.</p>
<p>Meanwhile, Dropbox wants to give you access to your files everywhere. Maybe they could keep your files encrypted on their servers, with encryption keys stored only on your desktop machine? Yes&#8230; until you want to access your files over the Web using a friend&#8217;s computer. And what if you want to share a file with a friend while they&#8217;re not online? Somehow you have to send them the decryption key. Dropbox must now ask its users to manage the sharing of these decryption keys (good luck explaining that to them), or must hold on to the decryption key and manage who gets the key&#8230;. which means storing the decryption keys on their servers. If you walk down the usability path far enough – in fact not all that far – it becomes clear that Dropbox probably needs to store the decryption key not too far from the encrypted files themselves. Encryption can&#8217;t protect you once you actually mean to decrypt the data.</p>
<p>The features users need often dictate where the decryption key is stored. The more useful the product, the closer the decryption key has to be to the encrypted data. Don&#8217;t think of encryption as a magic shield that miraculously distinguishes between good and bad guys. Instead, think of encryption as a mechanism for shrinking the size of the secret (one small encryption key can secure gigabytes of data), thus allowing the easy relocation of the secret to another location. That&#8217;s still quite useful, but it&#8217;s not nearly as magical as many imply it to be.</p>
<h4>what about Firefox Sync, Apple TimeMachine, SpiderOak, Helios, etc.</h4>
<p>But but but, you might be thinking, there <em>are</em> systems that store encrypted data and don&#8217;t store the decryption key. <a href="http://www.mozilla.org/en-US/mobile/sync/">Firefox Sync</a>. Apple&#8217;s <a href="http://www.apple.com/timecapsule/">TimeMachine backup system</a>. The <a href="http://spideroak.com">SpiderOak</a> online backup system. Heck, even my own <a href="http://heliosvoting.org">Helios Voting System</a> encrypts user votes in the browser with no decryption keys stored anywhere except the trustees&#8217; own machines.</p>
<p>It&#8217;s true, in some very specific cases, you can build systems where the decryption key is stored only on a user&#8217;s desktop machine. Sometimes, you can even build a system where the key is stored nowhere durably; instead it is derived on the fly from the user&#8217;s password, used to encrypt/decrypt, then forgotten.</p>
<p>But all of these systems have significant usability downsides (yes, even my voting system). If you only have one machine connected to Firefox Sync, and you lose it, you cannot get your bookmarks and web history back. If you forget your Time Machine or SpiderOak password, and your main hard drive crashes, you cannot recover your data from backup. If you lose your Helios Voting decryption key, you cannot tally your election.</p>
<p>And when I say &#8220;you cannot get your data back,&#8221; I mean you would need a mathematical breakthrough of significant proportions to get your data back. It&#8217;s not happening. Your data is lost. Keep in mind: that&#8217;s the whole point of not storing the decryption key. It&#8217;s not a bug, it&#8217;s a feature.</p>
<h4>and then there&#8217;s sharing</h4>
<p>I alluded to this issue in the Dropbox description above: what happens when users want to share data with others? If the servers don&#8217;t have the decryption key, that means users have to pass the decryption key to one another. Maybe you&#8217;re thinking you can use public-key encryption, where each user has a keypair, publishes the public encryption key, and keeps secret the private decryption key? Now we&#8217;re back to &#8220;you can&#8217;t get your data back&#8221; if the user loses their private key.</p>
<p>And what about features like Facebook&#8217;s newsfeed, where servers process, massage, aggregate, and filter data for users before they even see it? If the server can&#8217;t decrypt the data, then how can it help you process the data before you see it?</p>
<p>To be clear: if your web site has social features, it&#8217;s very unlikely you can successfully push the decryption keys down to the user. You&#8217;re going to need to read the data on your servers. And if your servers need to read the data, then a hacker who breaks into the servers can read the data, too.</p>
<h4>so the cryptographer is telling me that encryption is useless?</h4>
<p>No, far from it. I&#8217;m only saying that encryption with end-user-controlled keys has far fewer applications than most people think. Those applications need to be well-scoped, and they have to accompanied by big bad disclaimers about what happens when you lose your key.</p>
<p>That said, encryption as a means of partitioning power and access on the server-side remains a very powerful tool. If you have to store credit card numbers, it&#8217;s best if you build a subsystem whose entire role is to store credit-card numbers encrypted, and process transactions from other parts of your system. If your entire system is compromised, then you&#8217;re no better off than if you hadn&#8217;t taken those precautions. But, if only part of your system is compromised, encryption may well stop an attacker from gaining access to the most sensitive parts of the system.</p>
<p>You can take this encryption-as-access-control idea very far. An MIT team just <a href="http://css.csail.mit.edu/cryptdb/">published CryptDB</a>, a modified relational database that uses interesting encryption techniques to strongly enforce access control. Note that, if you have the password to log into the database, this encryption isn&#8217;t going to hide the data from you: the decryption key is on the server. Still, it&#8217;s a very good defense-in-depth approach.</p>
<h4>what about this fully homomorphic encryption thing?</h4>
<p>OK, so I lied a little bit when I talked about pre-processing data. There is a kind of encryption, called homomorphic encryption, that lets you perform operations on data while it remains encrypted. The last few years have seen epic progress in this field, and it&#8217;s quite exciting&#8230;. for a cryptographer. These techniques remain extremely impractical for most use cases today, with an overhead factor in the trillions, both for storage and computation time. And, even when they do become more practical, the central decryption key problem remains: forcing users to manage decryption keys is, for the most part, a usability nightmare.</p>
<p>That said, I must admit: homomorphic encryption <em>is</em> actually almost like magic.</p>
<h4>the special case of passwords</h4>
<p>Passwords are special because, once stored, you never need to read them back out, you only need to check if a password typed by a user matches the one stored on the server. That&#8217;s very different than a credit-card number, which does need to be read after it&#8217;s stored so the card can be charged every month. So for passwords, we have special techniques. It&#8217;s not encryption, because encryption is reversible, and the whole point is that we&#8217;d like the system to strongly disallow extraction of user passwords from the data-store. The special tool is a one-way function, such as <tt>bcrypt</tt>. Take the password, process it using the one-way function, and store only the output. The one-way function is built to be difficult to reverse: you have to try a password to see if it matches. That&#8217;s pretty cool stuff, but really it only applies to passwords.</p>
<p>So, if you&#8217;re storing passwords, you should absolutely be passing them through a one-way function. You could say you&#8217;re &#8220;hashing&#8221; them, that&#8217;s close enough. In fact you probably want to say you&#8217;re salting and hashing them. But whatever you do, you&#8217;re not &#8220;encrypting&#8221; your passwords. That&#8217;s just silly.</p>
<h4>encryption is not a magic bullet</h4>
<p>For the most part, encryption isn&#8217;t magic. Encryption lets you manage secrets more securely, but if users are involved in the key management, that almost certainly comes at the expense of usability and features. Web services should strongly consider encryption where possible to more strictly manage their internal access controls. But think carefully before embarking on a design that forces users to manage their keys. In many cases, users simply don&#8217;t understand that losing the key means losing the data. As my colleague Umesh Shankar says, if you design a car lock so secure that locking yourself out means crushing the car and buying a new one, you&#8217;re probably doing it wrong.</p>
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		<slash:comments>12</slash:comments>
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		<title>and the laws of physics changed</title>
		<link>http://benlog.com/articles/2011/07/03/and-the-laws-of-physics-changed/</link>
		<comments>http://benlog.com/articles/2011/07/03/and-the-laws-of-physics-changed/#comments</comments>
		<pubDate>Sun, 03 Jul 2011 20:39:44 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[identity]]></category>
		<category><![CDATA[privacy]]></category>
		<category><![CDATA[web]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1758</guid>
		<description><![CDATA[Google just introduced Google Plus, their take on social networking. Unsurprisingly, Arvind has one of the first great reviews of its most important feature, Circles. Google Circles effectively let you map all the complexities of real-world privacy into your online identity, and that&#8217;s simply awesome. You can think of Circles as the actual circles of [...]]]></description>
			<content:encoded><![CDATA[<p>Google just introduced <a href="http://plus.google.com">Google Plus</a>, their take on social networking. Unsurprisingly, Arvind has <a href="http://33bits.org/2011/07/03/google-and-privacy-a-roundup/">one of the first great reviews</a> of its most important feature, Circles. Google Circles effectively let you map all the complexities of real-world privacy into your online identity, and that&#8217;s simply awesome.</p>
<p>You can think of Circles as the actual circles of friends you have. The things that are easy to do in real life, like sharing a fun anecdote with the friends you generally go out with on Saturday nights, are easy to do in Circles. The things that are hard to do in real life, like planning your best friend&#8217;s surprise birthday party with all of his close friends but <em>without</em> him, are no easier in Circles: you have to make a new list of &#8220;everyone except Bob.&#8221; That&#8217;s great, because I don&#8217;t think our brains have evolved yet to really feel comfortable with a social model that supports all set operations, e.g. this circle <em>minus</em> this other circle. That&#8217;s usually how we get caught lying. (I mean the lies everyone tells as part of their normal social interactions.)</p>
<p>The most important point is that this feature shatters the previously universally accepted idea that privacy must change dramatically given social networking. For a few years, Facebook has defined the Laws of Physics of social networking. On Facebook, it&#8217;s not possible to show different people a different face. On Facebook, relationships are, for the most part, symmetrical. And so we all believed that this was the inevitable path forward with social networking. We conflated the fact that users wanted to connect online with the constraints that Facebook created, and we assumed users wanted those constraints. We forgot that software engineers define the Laws of Physics of the worlds they create. We weren&#8217;t living in the inherent world of social networking. We were living in Facebook&#8217;s definition of social networking.</p>
<p>We now know it doesn&#8217;t have to be this way. The Laws of Physics in the online world are mutable. Google just busted open a world of possibility. Users will question, now more than ever, why sharing must work the way it does on Facebook, given that Google has shown it can work differently.</p>
<p>It will make Facebook better. Which will make Google better. And so on. We may be witnessing the beginning of a new era of online privacy, a maturation of sorts. This is an incredibly exciting time.</p>
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		<slash:comments>6</slash:comments>
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		<title>with great power&#8230;</title>
		<link>http://benlog.com/articles/2011/06/12/with-great-power/</link>
		<comments>http://benlog.com/articles/2011/06/12/with-great-power/#comments</comments>
		<pubDate>Mon, 13 Jun 2011 02:31:52 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[policy]]></category>
		<category><![CDATA[privacy]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1735</guid>
		<description><![CDATA[When Arvind writes something, I tend to wait until I have a quiet moment to read it, because it usually packs a particularly high signal to noise ratio. His latest post In Silicon Valley, Great Power but No Responsibility, is awesome: We’re at a unique time in history in terms of technologists having so much [...]]]></description>
			<content:encoded><![CDATA[<p>When <a href="http://33bits.org">Arvind</a> writes something, I tend to wait until I have a quiet moment to read it, because it usually packs a particularly high signal to noise ratio. His latest post <a href="http://33bits.org/2011/06/11/in-silicon-valley-great-power-but-no-responsibility/">In Silicon Valley, Great Power but No Responsibility</a>, is awesome:</p>
<blockquote><p>
We’re at a unique time in history in terms of technologists having so much direct power. There’s just something about the picture of an engineer in Silicon Valley pushing a feature live at the end of a week, and then heading out for some beer, while people halfway around the world wake up and start using the feature and trusting their lives to it. It gives you pause.
</p></blockquote>
<p>So true. I&#8217;ve been thinking about this issue a lot recently, especially as good technologists in the Valley are in exceptionally good financial / career health, while the rest of the country, and <a href="http://www.nytimes.com/2011/06/05/us/05bcmountainview.html">sometimes even the other half of our cities</a>, are suffering through a long and deep recession.</p>
<p>Here&#8217;s one story that blew my mind a few months ago. Facebook (and I don&#8217;t mean to pick on Facebook, they just happen to have a lot of data) introduced a feature that shows you photos from your past you haven&#8217;t seen in a while. Except, that turned out to include a lot of photos of ex-boyfriends and ex-girlfriends, and people complained. But here&#8217;s the thing: Facebook photos often contain tags of people present in the photo. And you&#8217;ve told Facebook about your relationships over time (though it&#8217;s likely that, even if you didn&#8217;t, they can probably guess from your joint social network activity.) So what did Facebook do? They computed the graph of ex-relationships, and they ensured that you are no longer proactively shown photos of your exes. They did this in a matter of days. Think about that one again: in a matter of days, they figured out all the romantic relationships that ever occurred between their 600M+ users. The power of that knowledge is staggering, and if what I hear about Facebook is correct, that power is in just about every Facebook engineer&#8217;s hands.</p>
<p>Here&#8217;s another story. I used to lecture MIT Undergraduates about web security. My approach was basically: (a) hack a few of the student project web sites, then (b) hack a few public web sites to make the students understand how widespread the problems are. In late 2003, I showed students how to buy movie tickets for free (the price of the ticket was held in a hidden variable in a web form&#8230; duh). I ended my lecture with &#8220;but just because you <em>can</em> do this, doesn&#8217;t mean you <em>should</em>. Please don&#8217;t do this.&#8221; Over the years, I&#8217;ve received a few emails from former students to the tune of &#8220;hey Ben, you gave an awesome lecture, I still remember how a bunch of us went out to see Matrix 3 for free that weekend!&#8221;</p>
<p>I shudder to think about what happens when you put those two stories together. While the earliest hackers may have had a particularly well developed ethical sense, I get the sense that our profession&#8217;s average ethical sense doesn&#8217;t nearly measure up to the incredible power we have gained precipitously over the last 15 years.</p>
<p>And then there&#8217;s the additional point Arvind makes, which I&#8217;ve observed directly too:</p>
<blockquote><p>
I often hear a willful disdain for moral issues. Anything that’s technically feasible is seen as fair game and those who raise objections are seen as incompetent outsiders trying to rain on the parade of techno-utopia.
</p></blockquote>
<p>Yes! There&#8217;s this continued and surprisingly widespread delusion that technology is somehow neutral, that moral decisions are for other people to make. But that&#8217;s just not true. Lessig taught me (and a generation of other technologists) that Code is Law, or as I prefer to think about it, that Code defines the Laws of Physics on the Internet. Laws of Physics are only free of moral value if they are truly natural. When they are artificial, they become <em>deeply</em> intertwined with morals, because the technologists <em>choose</em> which artificial worlds to create, which defaults to set, which way gravity pulls you. Too often, artificial gravity tends to pull users in the direction that makes the providing company the most money.</p>
<p>A parting thought. In 2008, the world turned against bankers, because many profited by exploiting their expertise in a rapidly accelerating field (financial instruments) over others&#8217; ignorance of even basic concepts (adjustable-rate mortgages). How long before we software engineers find our profession in a similar position? How long will we shield ourselves from the responsibility we have, as experts in the field much like experts in <em>any other field</em>, to guide others to make the best decision <em>for them</em>?</p>
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		<slash:comments>7</slash:comments>
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		<title>(your) information wants to be free</title>
		<link>http://benlog.com/articles/2011/04/28/your-information-wants-to-be-free/</link>
		<comments>http://benlog.com/articles/2011/04/28/your-information-wants-to-be-free/#comments</comments>
		<pubDate>Thu, 28 Apr 2011 05:46:42 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[data]]></category>
		<category><![CDATA[privacy]]></category>
		<category><![CDATA[security]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1631</guid>
		<description><![CDATA[A couple of weeks ago, Epsilon, an email marketing firm, was breached. If you are a customer of Tivo, Best Buy, Target, The College Board, Walgreens, etc., that means your name and email address were accessed by some attacker. You probably received a warning to watch out for phishing attacks (assuming it wasn&#8217;t caught in [...]]]></description>
			<content:encoded><![CDATA[<p>A couple of weeks ago, Epsilon, an email marketing firm, was breached. If you are a customer of Tivo, Best Buy, Target, The College Board, Walgreens, etc., that means your name and email address were accessed by some attacker. You probably received a warning to watch out for phishing attacks (assuming it wasn&#8217;t caught in your spam filter).</p>
<p>Yesterday, the Sony Playstation Network of 75 million gamers <a href="http://www.reuters.com/article/2011/04/28/us-sony-idUSTRE73R0Q320110428">was compromised</a>. Names, addresses, and possibly credit cards were accessed by attackers. This may well be the largest data breach in history.</p>
<p>And a few days ago, it was discovered that <a href="http://radar.oreilly.com/2011/04/apple-location-tracking.html">iPhones keep track of your location</a> over extended periods of time and copy that data to backups, even if you explicitly tell your iPhone not to track your location. There are believable claims that <a href="http://www.pcmag.com/article2/0,2817,2383945,00.asp">law enforcement has already used this information</a> without a court order. Apple now says this was <a href="http://www.apple.com/pr/library/2011/04/27location_qa.html">a bug and they&#8217;re fixing it</a>.</p>
<p>In 1984, Stewart Brand famously said that <a href="http://en.wikipedia.org/wiki/Information_wants_to_be_free">information wants to be free</a>. John Perry Barlow reiterated it in the early 90s, and added &#8220;<a href="http://www.wired.com/wired/archive/2.03/economy.ideas_pr.html">Information Replicates into the Cracks of Possibility</a>.&#8221; When this idea was applied to online music sharing, it was cool in a &#8220;fight the man!&#8221; kind of way. Unfortunately, information replication doesn&#8217;t discriminate: your <em>personal data</em>, credit cards and medical problems alike, also want to be free. Keeping it secret is really, really hard.</p>
<p>I get the sense that many think Epsilon and Sony were stupidly incompetent, and Apple was evil. This fails to capture the nature of digital data. It&#8217;s just incredibly hard to secure data when one failure outweighs thousands of successes. In the normal course of development, data gets copied all over the place. It takes a concerted effort to enumerate the places where data end up, to design defensively against data leakage, and to audit the code after the fact to ensure no mistakes were made. One mistake negates all successes.</p>
<p>Here&#8217;s one way to get an intuitive feel for it: when building a skyscraper, workers are constantly fighting gravity. One moment of inattention, and a steel beam can fall from the 50th floor, turning a small oversight into a tragedy. The same goes for software systems and data breaches. The natural state of data is to be copied, logged, transmitted, stored, and stored again. It takes constant fighting and vigilance to prevent that breach. It takes <em>privacy and security engineering</em>.</p>
<p>The kicker is that, while it&#8217;s unlikely to get into the business of building skyscrapers by accident, it&#8217;s incredibly easy to find yourself storing user data long before you&#8217;ve laid out decent privacy and security practices: Sony built game consoles, and then one day they were suddenly storing user data. It&#8217;s also far too common for great software engineers to deceive themselves into thinking that securing user data is not so hard, because hey, they would never be as stupid as those Sony engineers.</p>
<p>So, am I excusing Epsilon, Sony, and Apple? Not at all. But if we keep thinking that they were just stupid/evil, then we are far from understanding and fixing the problem.</p>
<p>I&#8217;ve just finished reading <a href="http://gawande.com/the-checklist-manifesto">Atul Gawande&#8217;s The Checklist Manifesto</a>, which I strongly recommend. As industries mature (flying airplanes, practicing medicine, building complex software systems,&#8230;), they must build in processes to counteract inevitable human weaknesses. There&#8217;s bound to be resistance from experienced practitioners who see the introduction of process as insulting to their craft. Programmers are, in this sense, a lot like doctors. But it&#8217;s time to stop being heroes and start being professionals. Storing user data safely is easy until it&#8217;s not.</p>
<p>We are constantly fighting nature to meet our stated goals: we don&#8217;t want buildings to fall, disease to kill us, or private information to leak. For a little while, it&#8217;s okay to fail catastrophically and act surprised. But eventually, these failures are no longer surprising, they&#8217;re just negligent. That time of transition for software architects is now. Every company that dabbles in user data should assign a dedicated security and privacy team whose sole responsibility is to protect user data. We will not eliminate all failures, but we can do much, much better.</p>
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		<slash:comments>8</slash:comments>
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		<title>grab the pitchforks!&#8230; again</title>
		<link>http://benlog.com/articles/2011/04/19/grab-the-pitchforks-again/</link>
		<comments>http://benlog.com/articles/2011/04/19/grab-the-pitchforks-again/#comments</comments>
		<pubDate>Tue, 19 Apr 2011 17:49:30 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[crypto]]></category>
		<category><![CDATA[data]]></category>
		<category><![CDATA[privacy]]></category>
		<category><![CDATA[web]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1618</guid>
		<description><![CDATA[I&#8217;m fascinated with how quickly people have reached for the pitchforks recently when the slightest whiff of a privacy/security violation occurs. Last week, a few interesting security tidbits came to light regarding Dropbox, the increasingly popular cloud-based file storage and synchronization service. There&#8217;s some interesting discussion of de-duplication techniques which might lead to Oracle attacks, [...]]]></description>
			<content:encoded><![CDATA[<p>I&#8217;m fascinated with how quickly people have reached for the pitchforks recently when the slightest whiff of a privacy/security violation occurs.</p>
<p>Last week, a few interesting security tidbits came to light regarding <a href="http://dropbox.com">Dropbox</a>, the increasingly popular cloud-based file storage and synchronization service. There&#8217;s some interesting discussion of de-duplication techniques which might lead to Oracle attacks, etc., but the most important issue is that, suddenly, everyone&#8217;s realizing that Dropbox <em>could</em>, if needed, access your files. Miguel de Icaza wonders if Dropbox is pitching <a href="http://tirania.org/blog/archive/2011/Apr-19.html">snake oil</a>.</p>
<p>Yes, Dropbox staff can, if needed, access your files. I don&#8217;t mean to harp on my fellow technologists but&#8230; this has been obvious since day 1, because Dropbox offers a web-based interface to download your files, and even with the latest HTML5 technology, you&#8217;d be very hard-pressed to do in-browser file decryption. Let&#8217;s say you still don&#8217;t buy that, you still think that Dropbox might find a way to encrypt files and decrypt them in your browser. Dropbox also offers a password recovery mechanism, which means they can fully simulate you, the user, including, of course, getting at your files.</p>
<p>In other words, unless you&#8217;re ready to lose the convenience of password resets and web-based UI, Dropbox inherently has access to your files. Just like Facebook has access to your entire account, and Google to all of your docs, spreadsheets, etc. The only question is what kinds of internal safeguards do these companies have to prevent abuse by employees. Unless you&#8217;ve worked there, it&#8217;s hard to know. You could ask Dropbox to do third-party auditing, like Miguel proposes, but in my experience that provides little real security, since you have little way to know what that third-party actually did as part of their auditing (was it just &#8220;logic and accuracy&#8221; testing?)</p>
<p>The other thing we could ask is for the law to finally recognize that my files stored on Dropbox are no different than my files stored on a hard drive in my basement, from a legal perspective. They&#8217;re my property. And accessing them should require the same level of judicial oversight as a warrant to my home. That&#8217;s what a group of young MIT techies (myself included) and Harvard lawyers <a href="http://groups.csail.mit.edu/mac/classes/6.805/student-papers/fall98-papers/trespass/final.html">proposed in 1998</a>.</p>
<p>But back to Dropbox. Did they do something wrong? Yes, they did. They exaggerated their security and privacy claims. <em>Just like almost every other cloud data host today</em>. I wish, instead of picking on whichever startup suddenly succeeds, we picked on the industry as a whole. Stop talking about encryption in transit and encryption at rest in the same breath, as if they were the same thing. Stop using &#8220;encryption&#8221; as a synonym for &#8220;secure.&#8221; Stop saying &#8220;military-grade security.&#8221; Start being honest about who can access what.</p>
<p>And we, technologists, should stop with the drama, and not fall prey to the inflated expectations that marketing-heavy security policies have set. The Dropbox weaknesses should have been obvious to technologists from day one. The problem is that <em>all</em> privacy policies and security statements make exaggerated claims using reassuring keywords. Let&#8217;s harp on that.</p>
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		<title>degrees of trust: software vs. data hosts</title>
		<link>http://benlog.com/articles/2011/03/16/degrees-of-trust-software-vs-data-hosts/</link>
		<comments>http://benlog.com/articles/2011/03/16/degrees-of-trust-software-vs-data-hosts/#comments</comments>
		<pubDate>Wed, 16 Mar 2011 21:14:15 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[privacy]]></category>
		<category><![CDATA[web]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1584</guid>
		<description><![CDATA[Overjoyed by all the SSL goodness around me (Twitter offers SSL-only as an option, so does Facebook, Google offers 2-factor auth), I started dutifully upgrading my web browsing experience on Firefox, specifically installing the EFF Add-On that turns on HTTPS everywhere it can, in particular when using Google (it uses encrypted.google.com by default). I googled [...]]]></description>
			<content:encoded><![CDATA[<p>Overjoyed by all the SSL goodness around me (Twitter offers SSL-only as an option, so does Facebook, Google offers 2-factor auth), I started dutifully upgrading my web browsing experience on Firefox, specifically installing the <a href="https://www.eff.org/https-everywhere">EFF Add-On</a> that turns on HTTPS everywhere it can, in particular when using Google (it uses <a href="https://encrypted.google.com">encrypted.google.com</a> by default). I googled myself to test it out, and I found this <a href="http://www.cssquirrel.com/blog/2010/04/22/comic-update-moose-squirrel/">interesting blog post by CSS Squirrel</a> from a few months ago, in regards to the issue I have with Opera Mini.</p>
<p>CSS Squirrel says:</p>
<blockquote><p>
Ben Adida offered the following question as a counter: “Does privacy matter? Cause Opera Mini proxies all of your connections, even SSL, via its servers.” It’s a valid question, especially considering his expertise in the field of privacy and security.
</p></blockquote>
<p>Actually it&#8217;s a valid question regardless of my credentials <img src='http://benlog.com/wp-includes/images/smilies/icon_smile.gif' alt=':)' class='wp-smiley' /> </p>
<blockquote><p>
Not being an expert on how Opera does things, I poked at both Bruce Lawson and Molly Holzschlag, both Opera employees.</p>
<p>Both of them said “If you don’t trust us (Opera), then don’t use the service.”</p>
<p>[...]</p>
<p>So is Opera Mini fast? Yes. Is it secure? Yes.
</p></blockquote>
<p>But that&#8217;s not good enough. Trust is not a simple yes/no concept. I trust my dog walker to come into my home, walk my dog, and not go opening up drawers to find my medical records. But I&#8217;m not going to leave my medical records out in the open either, cause that&#8217;s just asking for trouble. I trust that the Opera browser, installed on my machine, is not phoning home my personal data, because that would be a huge breach of expectation. But if I use Opera Mini and all of my data is being shipped to Opera on every HTTP call, do I trust them never to look at it? Do I trust their security system to be so good that they won&#8217;t ever be hacked?</p>
<p>There are <em>degrees of trust</em>. I trust that most reputable installed software won&#8217;t phone home with my data. I trust that <em>some</em> data hosts won&#8217;t analyze my data too deeply, but certainly many will. And I&#8217;m pretty sure many data hosts will get hacked or will leak data unintentionally. So, it&#8217;s unreasonable to judge your software publishers and data hosts with the same degree of trust. There isn&#8217;t enough of a taboo against data hosts perusing your data. Facebook is mining our data, everyone knows it, and our general reaction is &#8220;oh well, what are you gonna do.&#8221; But if Microsoft Word scanned your hard drive and shipped your personal info back to Redmond, you&#8217;d be looking for a pitchfork right about now.</p>
<p>Opera Mini is misleading because it presents itself as an installable piece of software, when in fact it is almost a data host, and the degree of trust one should consider, when using Opera Mini, is a lot higher than that which is implied by their packaging.</p>
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		<title>the difference between privacy and security</title>
		<link>http://benlog.com/articles/2011/01/26/the-difference-between-privacy-and-security/</link>
		<comments>http://benlog.com/articles/2011/01/26/the-difference-between-privacy-and-security/#comments</comments>
		<pubDate>Wed, 26 Jan 2011 16:51:15 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[privacy]]></category>
		<category><![CDATA[security]]></category>
		<category><![CDATA[web]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1508</guid>
		<description><![CDATA[Facebook today rolled out new security features, both of which are awesome: SSL everywhere, and social re-authentication. True, SSL everywhere should probably be a default, even though I continue to believe that the cost is significantly underestimated by many privacy advocates. Regardless, this announcement is great news. The only nitpick I have, and I point [...]]]></description>
			<content:encoded><![CDATA[<p>Facebook today <a href="https://blog.facebook.com/blog.php?post=486790652130">rolled out new security features</a>, both of which are awesome: SSL everywhere, and social re-authentication. True, SSL everywhere should probably be a default, even though I continue to believe that the cost is significantly underestimated by many privacy advocates. Regardless, this announcement is great news.</p>
<p>The only nitpick I have, and I point it out because I think it&#8217;s significant in Facebook&#8217;s case, is that the announcement confuses privacy and security. The first paragraph mentions Data Privacy Day, then the general concept of controlling your data, then transitions to the new security features. But those are quite different.</p>
<p>Security is about <em>stopping the bad guys from stealing your data</em>. Privacy is about <em>controlling the good guys&#8217; handling of your data</em>. (Ron Rivest is said to have phrased this most eloquently, but I can&#8217;t find his quotation.)</p>
<p>So, SSL and social re-authentication provide security because they prevent bad guys from seeing your network traffic at the coffee shop or stealing your login. That&#8217;s fantastic, but it has little to do with privacy. If Facebook wanted to celebrate Data Privacy Day specifically, they might consider giving users more control over their data <em>on Facebook</em>. Maybe letting users control who gets to tag them in photos (i.e. not my stalker). Or letting users indicate fields by which advertisers cannot target them (i.e. sexual orientation.) Those would be privacy features.</p>
<p>I don&#8217;t mean to knock Facebook&#8217;s announcement: it&#8217;s great. But it&#8217;s about security, not privacy.</p>
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		<title>Facebook, the Control Revolution, and the Failure of Applied Modern Cryptography</title>
		<link>http://benlog.com/articles/2011/01/14/facebook-the-control-revolution-and-the-failure-of-applied-modern-cryptography/</link>
		<comments>http://benlog.com/articles/2011/01/14/facebook-the-control-revolution-and-the-failure-of-applied-modern-cryptography/#comments</comments>
		<pubDate>Fri, 14 Jan 2011 07:40:12 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[crypto]]></category>
		<category><![CDATA[privacy]]></category>
		<category><![CDATA[web]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1490</guid>
		<description><![CDATA[In the late 1990s and early 2000s, it was widely assumed by most tech writers and thinkers, myself included, that the Internet was a &#8220;Control Revolution&#8221; (to use the words of Andrew Shapiro, author of a book with that very title in 1999). The Internet was going to put people in control, to enable buyers [...]]]></description>
			<content:encoded><![CDATA[<p>In the late 1990s and early 2000s, it was widely assumed by most tech writers and thinkers, myself included, that the Internet was a &#8220;Control Revolution&#8221; (to use the words of Andrew Shapiro, author of a book with that very title in 1999). The Internet was going to put people in control, to enable buyers to work directly with sellers, to cut out the middle man. Why? Because the Internet makes communication and commerce vastly more efficient, obviating the need for a middle man to connect us.</p>
<p>Fast forward to 2011, and the world is vastly more centralized than it ever was. Almost everyone&#8217;s most intimate conversations are held by four companies. And one company knows basically everything about everyone under 25.</p>
<p>How did we get so giddy about the Internet that we didn&#8217;t see this coming? We missed an important detail: communication and commerce became vastly more efficient for <em>everyone</em>, including the would-be middle-men, the would be mediators. The Internet enabled economies of scale never before imagined. So while it is possible to host your own email server, it&#8217;s a lot easier to use gmail. While it&#8217;s possible to host your own web page, post your updates to your blog, subscribe to your friends&#8217; RSS feeds hosted at different blogs, it&#8217;s a heck of a lot easier to use Facebook. The Internet put the 1990s middle-men out of business then enabled a new breed of data mediators that provide incredibly valuable services no individual user can dream of performing on their own: apply massively parallel facial recognition to billions of photos to find that one picture of you and your best friend&#8217;s grandmother, do deep graph analysis to find your long-lost friends and suggest you connect with them, learn how to filter spam messages so efficiently (thanks to training by billions of messages received on behalf of millions of users) that the spam wars are effectively over.</p>
<p>The Internet has been vastly more empowering to mediators than to individuals. And so we have, in fact, a Control Revolution of a very different nature: one company, namely Facebook, is effectively shaping the future of social interactions, what&#8217;s acceptable and what&#8217;s frowned upon, what&#8217;s private and what&#8217;s not.</p>
<p>I say this without any value judgment, purely as an observation. Facebook is making the rules, and when the rules change in Palo Alto, 550 million people follow.</p>
<h4>The Failure of Applied Modern Cryptography</h4>
<p>Cryptography in the 1980s was about secrecy, military codes, etc. I&#8217;m not talking about that.</p>
<p>Modern Cryptography is about individuals achieving a common goal without fully trusting one another. Think of a secret-bid auction. Or an election. Or two people discovering which friends they have in common without revealing the friends they don&#8217;t have in common. In all of these cases, people come together to accomplish a common result, but they cannot fully trust one another since their incentives are not perfectly aligned: I want to win the auction by bidding only one dollar more than you, Alice wants her candidate to beat yours, and Bob would like to find out which movie stars you&#8217;re friends with even though he knows none.</p>
<p>Modern cryptography teaches us how to accomplish these tasks <em>without ever trusting a third party</em>. That&#8217;s hard to imagine if you&#8217;re not steeped in the field. But that&#8217;s what modern cryptography does: take an interaction that is easily imaginable with the help of a trusted third party that deals with each individual, and replace the trusted third-party with a beautiful mathematical dance that achieves the same end-goal. No centralization of data in one big database, no trusted dealer/counter/connector, just individuals exchanging coded messages in a particular order and obtaining a trustworthy result. Cryptographers call this secure multi-party computation.</p>
<p>Modern Cryptography would, if properly implemented, give us all the functionality of Facebook without the aggregation of everyone&#8217;s data in a single data center. And we couldn&#8217;t be further from this world if we tried! We are headed for a world of increased data centralization and increased reliance on trusted third parties. Because they&#8217;re vastly more efficient, have economies of scale that allow them to provide features we didn&#8217;t dream of just a few years ago, and of course because the economic incentives of becoming that trusted third party are staggering.</p>
<p>As a privacy advocate, and again without value judgment, I can&#8217;t imagine a more surprising consequence of a technology that was meant to empower the little guy. It is, in a word, shocking.</p>
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		<title>privacy icons</title>
		<link>http://benlog.com/articles/2010/12/27/privacy-icons/</link>
		<comments>http://benlog.com/articles/2010/12/27/privacy-icons/#comments</comments>
		<pubDate>Tue, 28 Dec 2010 01:16:57 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[privacy]]></category>
		<category><![CDATA[web]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1475</guid>
		<description><![CDATA[Aza Raskin has posted alpha 1 of the proposed Mozilla Privacy Icons. I was at the Mozilla-sponsored get-together where this was first discussed, and I&#8217;m really happy to see this moving forward. A few quick thoughts: the least useful of the icons is the &#8220;used only for intended use.&#8221; I don&#8217;t think that icon can [...]]]></description>
			<content:encoded><![CDATA[<p>Aza Raskin has posted alpha 1 of the proposed <a href="http://www.azarask.in/blog/post/privacy-icons/">Mozilla Privacy Icons</a>. I was at the Mozilla-sponsored get-together where this was first discussed, and I&#8217;m really happy to see this moving forward. A few quick thoughts:</p>
<ul>
<li> the least useful of the icons is the &#8220;used only for intended use.&#8221; I don&#8217;t think that icon can be boolean, because what, exactly is the intended use? This is one area where an icon alone probably won&#8217;t be enough, and a web site should list the intended uses.</li>
<p></p>
<li> machine-readability: yes, fantastic, I&#8217;m glad this is part of the story, it&#8217;s an incredibly important aspect of how we did this at Creative Commons. Now, hopefully, unlike what Aza said at the get-together a few months ago, Mozilla will stop poo-pooing <a href="http://rdfa.info">RDFa</a> and use it, rather than define yet another one-off standard for machine-readable, HTML-embedded data. You don&#8217;t have to invent everything, right Mozilla? <img src='http://benlog.com/wp-includes/images/smilies/icon_smile.gif' alt=':)' class='wp-smiley' /> </li>
<p></p>
<li> I really like the general concept of the data-retention icons. Very nice!</li>
<p></p>
<li> Want to be really ballsy? Default Firefox to all the green icons, and force the user to click through &#8220;you&#8217;re now okay with your data being sold&#8221; the first time they hit a site that has a red icon. The browser could even block the first time it sees a site without privacy icons, so the user is warned that there&#8217;s no telling what the site will do. It&#8217;s time the browsers start fighting back big time on privacy.</li>
<p>
</ul>
<p>Overall, very nice work.</p>
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		<title>Crisis in the Java Community&#8230; could they have used a secret-ballot election?</title>
		<link>http://benlog.com/articles/2010/12/09/crisis-in-the-java-community-could-they-have-used-a-secret-ballot-election/</link>
		<comments>http://benlog.com/articles/2010/12/09/crisis-in-the-java-community-could-they-have-used-a-secret-ballot-election/#comments</comments>
		<pubDate>Thu, 09 Dec 2010 20:06:40 +0000</pubDate>
		<dc:creator>ben</dc:creator>
				<category><![CDATA[crypto]]></category>
		<category><![CDATA[privacy]]></category>
		<category><![CDATA[security]]></category>
		<category><![CDATA[voting]]></category>

		<guid isPermaLink="false">http://benlog.com/?p=1472</guid>
		<description><![CDATA[There is a bit of a crisis in the Java community: the Apache Foundation just resigned its seat on the Java Executive Committee, as did two individual members, Doug Lea and Tim Peierls. From what I understand, the central issue appears to be that Oracle, the new Java &#8220;owner&#8221; since they acquired Sun Microsystems, is [...]]]></description>
			<content:encoded><![CDATA[<p>There is a bit of a crisis in the Java community: <a href="https://blogs.apache.org/foundation/entry/the_asf_resigns_from_the">the Apache Foundation just resigned its seat on the Java Executive Committee</a>, as did two individual members, <a href="http://gee.cs.oswego.edu/dl/html/jcp22oct10.html">Doug Lea</a> and <a href="http://tembrel.blogspot.com/2010/12/resigned-from-ec.html">Tim Peierls</a>. From what I understand, the central issue appears to be that Oracle, the new Java &#8220;owner&#8221; since they acquired Sun Microsystems, is paying lip service to the Java Community while taking the language and, more importantly, its licensing, into the direction they prefer, which doesn&#8217;t appear to be very open-source friendly.</p>
<p>That said, I&#8217;m not a Java Community expert, so I won&#8217;t comment much more on this conflict, other than to say, wait a minute, what&#8217;s this from Tim Peierls&#8217;s resignation note?</p>
<blockquote><p>
Several of the other EC members expressed their own disappointment while voting Yes. I&#8217;m reasonably certain that the bulk of the Yes votes were due to contractual obligations rather than strongly-held principles.
</p></blockquote>
<p>Wait a minute, the Executive Committee votes by public ballot? They&#8217;re influenced by contractual obligations? That&#8217;s fascinating, and that&#8217;s hardly democratic! It means that, even where standards bodies are concerned, the secret ballot might be a very interesting tool.</p>
<p>There are arguments against the secret ballot in this case, of course: maybe the Executive Committee members are representative of the Java Community, and as such they should serve their constituents? Much like legislators, their votes should be public so the community can decide whether or not to reelect them? In that case, contractual obligations to vote a certain way should be strictly disallowed or required to be published along with the vote&#8230; To whom are these Executive Committee members accountable? To themselves as well-intentioned guides of the Java community? To the people who elected them? It&#8217;s difficult to have it both ways, since one requires a secret ballot, and the other a public ballot.</p>
<p>Maybe the right solution is to publish all comments, but keep the ballots secret? There&#8217;s always a chance that a truly hypocritical member would consistently vote differently than their publicly stated opinions, but I&#8217;m not sure that risk is worse than the problems the Java Community just faced with what appears to be anything but a democratic vote. In a tough spot like this one, it seems to me that Executive Committee members should be able to vote their conscience without fear of retribution.</p>
<p>(Oh, and if the Java community is looking for a secure voting system, I might have a <a href="http://heliosvoting.org">suggestion</a>.)</p>
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