handslive: (Default)
There are a few things outstanding, naturally. But it's in our grubby little hands now along with the associated debt. Next up: moving, I suppose.

Won't keep me from giving a huge sigh of relief.

Posted via Journaler.
handslive: (Default)
Someone at work pointed to this yesterday (and I see Slashdot has a post).  If I point back here to my earlier post (TL;DR -- PIN selection is important if you're worried about the cops copying all your emails off your iPhone), one of the things I said was that for most people the 4 digit PIN would be fine, especially if you're backing up regularly and you've set the data wipe option (kicks in after 10 failures).  Well, make sure it isn't one of the 10 most popular PINs from that first link there: 1234, 0000, 2580, 1111, 5555, 5683, 0852, 2222, 1212, or 1998.
handslive: (Default)
Funky.  It looks like my choice of LJ style has gone bye-bye or at least been seriously de-tuned.  Well, something new to spend time and energy on later.
handslive: (Default)
Fireplace with hearth by HandsLive
Fireplace with hearth, a photo by HandsLive on Flickr.

I've uploaded a very small number of photos this time, but truthfully we're nearly there. We have a meeting on Monday to review final touches and discuss delivery. We should be moved in before the end of June, somewhat anyway.

handslive: (Default)
I've been following this at work a bit and Bruce Schneier recently linked to it on his blog.  This post is mostly my own notes about how the passcode on my phone protects some of my data and how well it does that.  But I've tried to write it up so it's reasonably consumable.

ElcomSoft has a suite of tools for performing forensic analysis on devices running iOS 4 and they've recently revealed some improvements, especially in the area of key recovery. Some encrypted files on the device, like email messages, require that they have the user's passcode. ElcomSoft has some technical details on how the encryption works, but a brief overview is probably helpful here.

The iOS device has some encryption keys stored internally that are not written off the device, even for syncing or backups. There are keys derived from the unique device key embedded in the hardware. There is a key derived from the user's passcode and the unique device key. There are escrow keys derived from escrow pairing records and the unique device key. These are used for device syncing with trusted computers so that the user's passcode isn't needed every time files are accessed via iTunes. Finally, there are erasable keys kept in common storage. These are part of the keychain that stores application secrets like account details, usernames, and passwords. Developers can control whether these are stored with backups or only kept on the device when developing their apps.

Using the escrow keys and the unique device keys, it's possible to obtain access to some files without knowing the passcode. However, full access still requires the passcode in order to decrypt everything.

Their approach allows brute-forcing the passcode, but they access this via some direct interface, bypassing the API that would trigger a device wipe. This also means the delays inserted by the front panel don't apply and the only limitation is the speed of the device. They claim to be able to break a 4 digit passcode in 40 minutes maximum, 20 minutes on average. That's 250 tries a minute. Just over 4 tries a second. Some anecdotal evidence from users of the passcode breaking tool suggests that, at least for non-law enforcement versions of the product, they will stop processing after some period of time, but this is obviously a configurable setting in the code if nowhere else. For the rest of this discussion, I'll assume they can keep guessing as long as their software, the device, and the universe itself keep functioning.

If you stick to a 4 character code, but make it lower case alphanumeric (36 characters), then there are 1,679,616 possibilities. Maximum time to crack this is 6,718 minutes (or just over 4.5 days). The average time to crack would be just over 2 days.

If you choose a 4 character code, lower case alphanumeric with symbols (no mixed case due to usability), then complexity is based on which punctuation this adds to the set. On the iPhone, this is -/:;()$&@".,?!' if you don't go to the next screen of keys. That's 15 additional symbols, not the full 32 you'd get with a US keyboard. This is a total of 51 possible characters or a namespace of 6,765,201. Maximum time to crack this is 27,060 minutes (or almost 19 days, less than 3 weeks). That means over a week on average. A nice increase over 2 days, but not enough to feel comfortable with.

Let's suppose you're completely paranoid. The iPhone supports 35 punctuation marks (or mine does). Our total character set is now 97. If we use an 8 character passcode, our namespace is 7,837,433,594,376,961. We can crack this in 31,349,734,377,508 minutes or 59,645,613 years. About 30 million years on average. That's more like it. But I'd be happy with a middle ground.

I'm assuming this attack gets better as iPhone hardware gets faster -- the limiting factor is how many attempts it will let you make. So suppose I'd like it to take them at least a year on current hardware. There are 525,600 minutes in a 365-day year. This is 131,400,000 guesses:
  • a 9 digit code (10x stronger than we need),
  • a 6 character alphanumeric, lower case code (20x stronger than we need),
  • a 5 character alphanumeric, lower case code with limited punctuation (ie. our 51 character set above -- about 3x stronger than we need), or
  • a 5 character code using the full set (about 80x stronger than we need).

Most of my reason for going to this level of detail isn't that I'm looking to defeat law enforcement efforts to scan my phone. Rather, my assumption is that ElcomSoft's approach is dependent on design flaws and vulnerabilities in iOS's current device protection. This means I expect that people who are not law enforcement to be able to exploit the same flaws and vulnerabilities.

Today, this would only be the result of a targeted attack. The techniques require detailed inside knowledge of the iOS architecture and at least physical possession of the device. If I forget my phone somewhere or it gets stolen, I'm probably not at any risk of someone using these techniques. Frankly, if you have the device set to wipe after 10 tries, a 4 digit passcode is more than enough (just don't pick sequential or repeating digits, like 1234 or 1111).

In another year or two years, though, ElcomSoft's tools may have been stolen, leaked, or duplicated. When that happens, the risk goes up that someone taking my phone may know how to get the data out or may know someone who does.  I think there's still some question whether the device itself is more valuable than the data on it, but some basic protection (a 5 character code isn't that bad) seems cheap to me.
handslive: (Default)
In the alt-text for this XKCD, Randall suggests that following the first content related link (ie not in italics and not in parentheses) on any Wikipedia post will lead you inevitably to philosophy.  Naturally, I had to try this, but it doesn't seem to work for me.  Once you hit mathematics, the links lead the reader in a circle that comes back to mathematics.  Many pages lead to this topic, so this seems like a fundamental flaw in his proposed logic or a lack of understanding of his rules on my part.  Or, he's satisfied that he's ended up in "philosophy" once he reaches "property (philosophy)".  If I skip loops by moving on to the second link in an affected post, then, yes, I do seem to end up at philosophy in the half dozen pages I tried.  Sometimes by very convoluted paths.

This was an easy bit of thumb-twiddling during a meeting where i only had to listen to folks on the phone.

Fireplace!

May. 10th, 2011 10:38 pm
handslive: (Default)
Fireplace! by HandsLive
Fireplace!, a photo by HandsLive on Flickr.

A bunch of tiling is done. Some backsplashes are done. Some lighting is starting to be installed. But, most importantly, the fireplace is bricked. :-)

handslive: (Default)
Plywood ceiling by HandsLive
Plywood ceiling, a photo by HandsLive on Flickr.

Things are proceeding quickly as we get down to the final bits of work. The ceiling (as you can see) is almost done. More things are being completed all the time.

handslive: (Default)

View from the hallway
Originally uploaded by HandsLive
Drywalling is finished, more or less, and painting and finishing has started. So, it must be time to post more pictures.
handslive: (Default)

West exterior
Originally uploaded by HandsLive
So, the drywall is coming along on the second floor and, to my surprise, the siding has also started. The colour is everything I'd hoped for.
handslive: (Default)
This is a problem I've been thinking about a lot.  I have a significant list of passwords, PINs, passphrases, and bits of profile information for the sites and applications they get used on.  My partner (or at least my estate) should have access to the most up to date version of this information.  It gets changed regularly and this means a safe deposit box isn't really the best choice.  What I need is a kind of digital escrow service that I don't have to hand my keys over to.

Thinking about how to do this )
handslive: (Default)

Office
Originally uploaded by HandsLive
Did a walk-through with the electrician yesterday. This was also the first time I'd been up there when it wasn't raining or overcast, and the first time [livejournal.com profile] purplejavatroll had been up there at all.
handslive: (hiking)

Blue Dragonfly
Originally uploaded by HandsLive
[livejournal.com profile] purplejavatroll , [livejournal.com profile] mouseman , and I went on a hike at Blackfoot Provincial Recreation Area out near Cooking Lake today. A whole bunch of photos posted as a result.

If you look closely at my Flickr feed, there are also pictures of the house and some random shots I somehow hadn't gotten around to posting previously.

The Blackfoot Rec Area shots are here.

Sadistics

Jun. 30th, 2010 08:14 am
handslive: (coding)
I sucked at statistics when I took the required courses at university.  But I also developed an appreciation for the kind of bent thinking statisticians have to do sometimes when looking at the data they analyze.  Yesterday I saw a remarkably fun example, which I probably wouldn't have posted about frankly, that's related to an older problem first proposed by Martin Gardner called the Two Children Problem.  There's an excellent article about it here (warning: contains a light coating of math and fun thinking about sampling biases).

The reason I'm posting at all is because /. then had a link to a fantastic report on Daily Kos about rigged poll results and how the company they had contracted for polling services was defrauding them.  That one contains scads of statistical analysis.  It's also fascinating to me because tests for randomness are fascinating to me (and seeing human biases creep in because of our assumptions about randomness is even cooler).  It's good reading just to see what bad data looks like and how even simple tests (the first test is so simple you could teach it to junior high school students, I think) can make you skeptical.
handslive: (Default)

Front door
Originally uploaded by HandsLive
The big news this week is that the builder has made a lot of progress on the roof. The house looks more like a house as a result.


Livingroom and front door
Livingroom and front door
Originally uploaded by HandsLive
I also stepped inside and took a few shots. This gives you an idea what the living room would be like.


There's some others on Flickr.
handslive: (hiking)
On Monday, some of us went out to Clifford E Lee again.  There are photos here.

Also, more work has been done on the house.  There's some of a second story there now.

More house

Apr. 26th, 2010 03:45 pm
handslive: (Default)

From the front
Originally uploaded by HandsLive
We stopped by to checkout the stump grinding that was done a week and a half ago (and it looks good). More of the shell is up now, although it's not ready to be poured yet.

We interrupted a coffee break that two of the guys were having (it was around 3:30pm). They told us they've never had so many people stop by to ask questions about a house before this one. Apparently, the stack of maple (before we put most of it away anyway) was also a source of some questions, which is no surprise.

Today was spent talking to the two window & door suppliers the builder got quotes from.
handslive: (coding)
Way back when, I posted this screed on passwords.  In there I said:

In cryptography, the strength of a key is generally considered on the basis of how many operations an attacker would have to perform in order to break it.  My thinking is that password strength should be considered the same way.

But, frankly, I didn't do a good job of backing this statement up.  All you might say is that I didn't like traditional statements about "entropy" because it relates to natural language phrases, which is in part where the NSA's model comes from for cryptanalysis.  Passwords are not simply part of the collective space of language after all.  They have unique characteristics based on context that shape the likelihood of the user's password, its guessability.

I had the chance last week to read the article pointed to by this Bruce Schneier blog post.  He links to another blog post by one of the authors.  The author includes a link to the paper as a PDF.  If you're just that lazy, I've saved you a couple of steps.  Their study is based around security questions (a popular topic here at work) and there's some tasty bits in there.  They pretty much nail the "strength" question with the comment that the attacker only needs the 3 most popular answers.  They don't mention that the attacker also needs the usernames, which is worth mentioning, but somewhat to the side.

In any case, they have their own model for calculating entropy based on "guessability" assuming you have a data set to perform the stats against.  This gives a good measure to compare against.  A part of me wonders if we can reasonably use two big password file disclosures I can think of (a MySpace phishing leak from 2006 and the RockYou password database breach) as a basis for measurement.  RockYou is probably the more statistically significant leak, but folks have done analysis on both incidents.

The paper that Schneier linked to also references work that's been done to tune credential choices by using an entropy measure to pass or fail what the user enters.  Many sites now have strength meters for password entry, which are usually either checklists of attributes your password has or, in some cases, a zero sum game of good points and bad points.  This idea takes that to its game theory conclusion by suggesting that you could measure the statistical likelihood of the password against a set and agree that no attacker will try that one except in brute force cases.  The question is where does the set come from?

As a security practice, no one I know is building a database of the passwords people put in to their systems.  In fact, we're trying to make it hard to even know what the answer is you gave for the silly security question in your profile.  But without full knowledge of the set, how do we tune our statistics in order to provide useful feedback?  This is doubly interesting to me because John the Ripper uses a small packed database to generate brute force guesses and this is supposedly based on a statistical model of likely character combinations.  I don't know exactly what the developer for John used as his basis.  The documentation just says "based on my experience cracking passwords".  On the one hand, this means the attacker is doing his own research.  On the other, it would be nice to tune things for locale and user audience.

In spite of how good the research was on this, I wonder if it will affect how online systems manage passwords or how password-based systems are designed.
handslive: (coding)
[Posting from the conference]

For the umpteenth time, I've heard someone talk about the ease of switching to a different telecom provider if your current one went down or, worse, out of business.  Maybe this is a regional thing, but it makes me wonder what they're smoking.  I think a lot of these people have no idea to what degree core facilities and infrastructure are shared by more than one vendor, but usually operated by only one or two of them.  There are places in this country where this is even more the case.  Think northern BC or the Yukon.

Recent stories about businesses impacted by an FBI investigation into fraudulent use of VoIP services should come to mind.  Yes, you can switch to a different data centre if your current data centre goes away.  Can you afford it when your core functions are gone?  It turns out, mostly you can't.

The IT blogosphere thinks of the cloud as some ubiquitous computing platform, but it's not.  It's highly distributed in the sense that you and your services are not in the same place (I don't think I live anywhere near a Google data centre for example), but it's not ubiquitous.  The network may be ubiquitous, but even that's highly variable.  I do not have good network access at my parents' farm, for example.  Not on the cellular network and not on land line networks.

5 subjects

Apr. 1st, 2009 08:03 pm
handslive: (Default)
Comment on this post and I will give you 5 subjects/things I associate with you.  Then post this in your LJ and elaborate on the subjects given.  As provided by [livejournal.com profile] buhrger.

Encryption

I have at best an amateur's appreciation for it.  The very first thing I found out about it at work is that encrypting things is easy.  Managing encryption keys is hard.  Encrypting them is easy for much the same reason that programming is easy but writing programs is hard.  A lot of smart people have done the heavy lifting for me.  Then they hand over the tools and I'm free to make amazingly destructive and asinine mistakes.

The most recent thing I've learned is that we (meaning security folks for the most part) do not know what people actually do with the information they handle every day.  And once you learn what they do, it doesn't tell you why.  Adding encryption into that mix in order to control access to information or at least prevent it from leaking out means having to learn why in a lot of cases.  Managing people using encryption is also hard.

Peter Watts

Over beer at a con in 2007, Peter described a premise for (I'm going to make up a term here) a generative device.  I say "generative" rather than "literary" because it wasn't clear as the discussion progressed that he was talking about a novel or even a narrative per se.  He had several thoughts for how the premise might expand, change, progress, or be experienced by the audience.

He's posted snippets of text in his blog that refer to this idea and they're definitely enticing.  I mention this simply because I can imagine this premise in several different media and I wouldn't mind experiencing it in any of them.  In a sense it's too bad he couldn't produce something in all of those media formats.  And I only say "too bad" because I can't imagine such a broad swathe of people understanding what they were looking at and going, "Oh, yes, please."

Vague enough for you?

Poetry, Piano, Aikido

Yeah, I'm combining all 3 of these.  The point of commonality I'm going to hitch them to is "art".  Weirdly enough, I don't mind saying that I have some handle on making "art".  I may not be any good at these arts, but I have felt and directed consciously the outcomes of some of my efforts in them (whether the results were any good is pretty dubious).  This is my preface for a comment about what could laughingly be called my path for "art".

I've been fiddling with poetry longer than I've been playing piano, and doing both of those for longer than I've played around in martial arts.  Much longer than I've been learning aikido.  But I'm going to start from aikido because I think that's where I learned my first steps towards treating it like an art.

If you troll back through some of my first postings on LJ (don't do it!), there are comments about the role of intention in my training.  This is the biggest thing for me and it was my first realization about training.  I want to do what I intend.  Prior to understanding this, most of my efforts were focused around technical skill and a reactive process.  I would feel my partner move a certain way or anticipate the movement and react to this with an appropriate technique.

When [livejournal.com profile] buhrger gave me these 5 topics with the challenge to combine some of them, it occured to me that this starting point of intention was something that had also been developing in my poetry and music.  From the very beginning, playing piano was not about technique for me, but about bringing out the music I felt or sometimes heard inside.  To a lesser extent my early writing was the same.  This isn't any kind of unique experience.  What's the point of angsty teenage poetry in the first place?  To bring out feelings, images, and an expression of oneself in words.  But, again, the process is inherently reactive; it occurs in response to the feelings that prompt expression.  So, I'm not saying how I approached it was special, but that doing what I intend in music or writing is really just the same creative process that many people go through.

Where I've moved somewhat in my aikido is in the shaping and control of my intention.  I don't feel I'm at the point where that happens regularly or even consistently.  It's certainly easier in some exercises than others.  Previously, for example, I'd have said it didn't matter which way I moved to avoid an attack; there would be an appropriate technique to do from my new position.  Now, I'm starting to feel like there may be a particular outcome or expression of intent that should be present in my movement.  This will mean I must move to a particular place or even that I actively work to create the situation that allows that movement.  It isn't enough to intend to avoid the attack.

This is something that I'm not sure I have in my writing.  It may be the thing that is missing (and there must be something missing).  Similarly, I'm not sure that I have this ability with the music I've made.  But I think I understand what has to be done in order to begin learning it there.  I can feel where I need to stretch myself.  Truthfully, I feel less and less like someone with any artistic sense these days, so it's not like I'm regularly and honestly developing myself.  Makes the whole discussion above feel horribly pretentious.  But I tied the topics together anyway.
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