On Language

I was irked to see a tweet “Learned a new word! Pseudoarboricity: the number of pseudoforests needed to cover a graph. Yes, it is actually a word and so is pseudoforest.” The idea that some letter combinations are “actual words” implies that others are “not actual words,” and thus, that there is some authority who may tell me what letter combinations I am allowed to use or understand.

Balderdash. Adorkable balderdash, but balderdash nonetheless.

As any student of Orwell shall recall, the test of language is its comprehensibility, not its adhesion to some standard. As an author, I sometimes hear from people who believe themselves to be authorities, or who believe that they may select for me authorities as to the meanings of words, and who wish to tell me that my use of the word “threat” threatens their understanding, that the preface’s explicit discussion of the many plain meanings of the word is insufficient, or that my sentences are too long, comma-filled, dash deficient or otherwise Oxfordless in a way which seems to cause them to feel superior to me in a way they wish to, at some length, convey.


In fact, on occasion, they are irked. I recommend to them, and to you, “You Are What You Speak.”

I wish them the best, and fall back, if you’ll so allow, to a comment from another master of language, speaking through one of his characters:

‘When I use a word,’ Humpty Dumpty said, in rather a scornful tone, ‘it means just what I choose it to mean — neither more nor less.’
‘The question is,’ said Alice, ‘whether you can make words mean so many different things.’
‘The question is,’ said Humpty Dumpty, ‘which is to be master — that’s all.’

Conference Etiquette: What’s New?

So Bill Brenner has a great article on “How to survive security conferences: 4 tips for the socially anxious
.” I’d like to stand by my 2010 guide to “Black Hat Best Practices,” and augment it with something new: a word on etiquette.

Etiquette is not about what fork you use (start from the outside, work in), or an excuse to make you uncomfortable because you forgot to call the Duke “Your Grace.” It’s a system of tools to help otherwise awkward social interactions go more smoothly.

We all meet a lot of people at these conferences, and there’s some truth behind the stereotype that people in technology are bad at “the people skills.” Sometimes, when we see someone, there will be recognition, but the name and full context doesn’t come rushing back. That’s an awkward moment, and it’s worth thinking about the etiquette involved.

When you know you’ve met someone and can’t recall the details, it’s rude to say “remind me who you are,” and so people will do a bunch of things to politely encourage reminders. For example, they’ll say “what’s new” or “what have you been working on lately?” Answers like “nothing new” or “same old stuff” are not helpful to the person who asked. This is an invitation to talk about your work. Even if you haven’t done anything new that’s ready to talk about, you can say something like “I’m still exploring the implications of the work I did on X” or “I’ve wrapped up my project on Y, and I’m looking for a new thing to go frozzle.” If all your work is secret, you can say “Oh, still at DoD, doing stuff for Uncle Sam.”

Whatever your answer will be, it should include something to help people remember who you are.

Why not give it a try this RSA?

BTW, you can get the best list of RSA parties where you can yell your answers to such questions at “RSA Parties Calendar.”

IOS Subject Key Identifier?

I’m having a problem where the “key identifier” displayed on my ios device does not match the key fingerprint on my server. In particular, I run:


% openssl x509 -in keyfile.pem -fingerprint -sha1

and I get a 20 byte hash. I also have a 20 byte hash in my phone, but it is not that hash value. I am left wondering if this is a crypto usability fail, or an attack.

Should I expect the output of that openssl invocation to match certificate details on IOS, or is that a different hash? What options to openssl should produce the result I see on my phone?

[update: it also does not match the output or a trivial subset of the output of

% openssl x509 -in keyfile.pem -fingerprint -sha256
(or)

% openssl x509 -in keyfile.pem -fingerprint -sha512

]

[Update 2: iOS displays the “X509v3 Subject Key Identifier”, and you can ask openssl for that via -text, eg, openssl x509 -in pubkey.pem -text. Thanks to Ryan Sleevi for pointing me down that path.]

Think Like An Attacker? Flip that advice!

For many years, I have been saying that “think like an attacker” is bad advice for most people. For example:

Here’s what’s wrong with think like an attacker: most people have no clue how to do it. They don’t know what matters to an attacker. They don’t know how an attacker spends their day. They don’t know how an attacker approaches a problem. Telling people to think like an attacker isn’t prescriptive or clear.

And I’ve been challenging people to think like a professional chef to help them understand why it’s not useful advice. But now, I’ve been one-upped, and, depending on audience, I have a new line to use.

Last week, on Veracode’s blog, Pete Chestna provides the perfect flip of “think like an attacker” to re-frame problems for security people. It’s “think like a developer.” If you, oh great security guru, cannot think like a developer, for heavens sake, stop asking developers to think like attackers.

What to do for randomness today?

In light of recent news, such as “FreeBSD washing Intel-chip randomness” and “alleged NSA-RSA scheming,” what advice should we give engineers who want to use randomness in their designs?


My advice for software engineers building things used to be to rely on the OS to get it right. That defers the problem to a small number of smart people. Is that still the right advice, despite recent news? The right advice is pretty clearly not that a normal software engineer building in Ruby on Rails or asp.net should go and roll their own. It also cannot be that they spend days wading through debates. Experts ought to be providing guidance on what to do.

Is the right thing to hash together the OS and something else? If so, precisely what something else?

A Quintet of Facebook Privacy Stories

It’s common to hear that Facebook use means that privacy is over, or no longer matters. I think that perception is deeply wrong. It’s based in the superficial notion that people making different or perhaps surprising privacy tradeoffs are never aware of what they’re doing, or that they have no regrets.

Some recent stories that I think come together to tell a meta-story of privacy:

  • Steven Levy tweeted: “What surprised me most in my Zuck interview: he says the thing most on rise is ‘sharing with smaller groups.'” (Tweet edited from 140-speak). I think that sharing with smaller groups is a pretty clear expression that privacy matters to Facebook users, and that as Facebook becomes more a part of people’s lives, the way they use it will continue to mature. For example, it turns out:
  • 71% of Facebook Users Engage in ‘Self-Censorship’” did a study of people typing into the Facebook status box, and not hitting post. In part this may be because people are ‘internalizing the policeman’ that Facebook imposes:
  • Facebook’s Online Speech Rules Keep Users On A Tight Leash.” This isn’t directly a privacy story, but one important facet of privacy is our ability to explore unpopular ideas. If our ability to do so in the forum in which people talk to each other is inhibited by private contract and opaque rules, then our ability to explore and grow in the privacy which Facebook affords to conversations is inhibited.
  • Om Malik: “Why Facebook Home bothers me: It destroys any notion of privacy” An interesting perspective, but Facebook users still care about privacy, but will have trouble articulating how or taking action to preserve the values of privacy they care about.

The Psychology of Password Managers

As I think more about the way people are likely to use a password manager, I think there’s real problems with the way master passwords are set up. As I write this, I’m deeply aware that I’m risking going into a space of “it’s logical that” without proper evidence.

Let’s start from the way most people will likely come to a password manager. They’ll be in an exploratory mood, and while they may select a good password, they may also select a simple one that’s easy to remember. That password, initially, will not be protecting very much, and so people may be tempted to pick one that’s ‘appropriate’ for what’s being protected.

Over time, the danger is that they will not think to update that password and improve it, but their trust in the password manager will increase. As their trust increases, the number of passwords that they’re protecting with a weak master password may also increase.

Now we get to changing the master password. Assuming that people can find it, how often will someone wake up and say “hey, I should change my master password?” Changing a master password is also scary. Now that I’ve accumulated hundreds of passwords, what happens if I forget my new password? (As it turns out, 1Password makes weekly backups of my password file, but I wasn’t aware of that. Also, what happens to the old files if I change my master password? Am I now exposed for both? That’s ok in the case that I’m changing out of caution, less ok if I’m changing because I think my master was exposed.)

Perhaps there’s room for two features here: first, that on password change, people could choose to have either master password unlock things. (Encrypt the master key with keys derived from both the old & new masters. This is no less secure than having backups available, and may address a key element of psychological acceptability.) You’d have to communicate that this will work, and let people choose. User testing that text would be fascinating.

A second feature might be to let people know how long they’ve been using the same master password, and gently encourage them to change it. This one is tricky mostly because I have no idea if it’s a good idea. Should you pick one super-strong master and use it for decades? Is there value to changing it now and again? Where could we seek evidence with which to test our instincts? What happens to long term memory as people age? Does muscle memory cause people to revert their passwords? (I know I’ve done it.) We could use a pattern like the gold bar to unobtrusively prompt.

A last element that might improve the way people use master passwords would be better browser integration. Having just gone to check, I was surprised how many sites my browser is tracking. Almost all of them were low value, and all of them now are. But why do we have two places that can store this, especially when one is less secure than the other. A browser API that allows a password manager to say “I’ve got this one” would be a welcome improvement.

Studying these ideas and seeing which ones are invalidated by data gathering would be cool. Talking to people about how they use their password managers would also be interesting work. As Bonneau has show, the quest to replace passwords is going to be arduous. Learning how to better live with what we have seems useful.

1Password & Hashcat

The folks at Hashcat have some interesting observations about 1Password. The folks at 1Password have a response, and I think there’s all sorts of fascinating lessons here.

The crypto conversations are interesting, but at the end of the day, a lot of security is unavoidably contributed by the master password strength. I’d like to offer up a simple contribution. Agilebits should make two non-cryptographic changes in addition to any crypto changes.

These relate to the human end of the issue, and how real humans make decisions. That is, picking a master password is a one time event, and even if there’s a strength meter, factors of memorability, typability, etc all come into play when the user selects a password when first installing 1Password.

Those human factors are not good for security, but I think they’re addressable.

First, the master password entry screens should display the same password strength meter that’s displayed everywhere else. It’s all well and good to discuss in a blog post that people need strong master passwords, but the software should give regular feedback about the strength of that master password. Displaying a strength meter each time it’s entered creates some small risk of information disclosure via shoulder-surfing, and adds pressure to make it stronger.

Second, they should make it easier to change the master password. I looked around, couldn’t figure out how to do so in a few minutes. [Update: It’s in preferences, security. I thought I’d looked there, may have missed it.]

1password

If master passwords are so important, then it’s important for the software to help its customers get them right.

There’s an interesting link here to “Why Johnny Can’t Encrypt.” In that 1999 paper, Whitten and Tygar made the point that all the great crypto in PGP couldn’t protect its users if they didn’t make the right decisions, and making those decisions is hard.

In this case, the security of password vaults depends not only on the crypto, but also on the user interface. Figuring out the mental models that people have around password storage tools, and how the interface choices those tools make develop those mental models is an important area, and deserves lots of careful attention.

Gamifying Driving

P90115441 highRes 640x419

…the new points system rates the driver’s ability to pilot the MINI with a sporty yet steady hand. Praise is given to particularly sprightly sprints, precise gear changes, controlled braking, smooth cornering and U-turns executed at well-judged speeds. For example, the system awards maximum Experience Points for upshifts carried out within the ideal rev range and in less than 1.2 seconds. Super-slick gear changes prompt a “Perfect change up” message on the on-board monitor, while a “Breathtaking U-turn” and a masterful touch with the anchors (“Well-balanced braking”) are similarly recognised with top marks and positive, MINI-style feedback.

For more, see “MINI Connected Adds Driving Excitement Analyser.”

Now, driving is the most dangerous thing most of us do on a regular basis. Most Americans don’t get any supplemental driving instruction after they turn 17. So maybe there’s actually something to be said for a system that incents people to drive better.

I can’t see any possible issues with a game pushing people towards things that are undesirable in the real world. I mean, I’m sure that before suggesting a U-turn, the game will use the car’s adaptive cruise control radar to see what’s around, even if the car doesn’t have one.

Happy Data Privacy Day! Go check out PrivacyFix

It’s Data Privacy Day, and there may be a profusion of platitudes. But I think what we need on data privacy day are more tools to let people take control of their privacy. One way to do that is to check your privacy settings. Of course, the way settings are arranged changes over time, and checking your settings regularly is a drain.

Enter PrivacyFix.

PrivacyFix is a Firefox & Chrome plugin that you might want to check out. It looks at your Facebook and G+ settings, and helps you fix things. It also helps you send opt-out email to web site privacy addresses, which is awesome.

Not having a Facebook or G+ account, I can’t really test it. I do find the model of a plugin that works when you’re on their site (versus local UI) to be confusing. But maybe I’m not their target audience. Anyway, I did want to refer back to my Lessons from Facebook’s Stock Slide, in which I talked about intent versus identity.

Facebook tracks
Google tracks

I don’t know if PrivacyFix’s estimates of revenue are accurate. But unless they’re off by 2 orders of magnitude for each of Facebook (under-estimating) and Google (over-estimating), then wow.