Sony-style Attacks and eMail Encryption

Friday, December 19, 2014 

Some of the summaries of the Sony attacks are a little despairing of the viability of internet security, for example Schneier:

This could be any of us. We have no choice but to entrust companies with our intimate conversations: on email, on Facebook, by text and so on. We have no choice but to entrust the retailers that we use with our financial details. And we have little choice but to use butt services such as iButt and Google Docs.

I respectfully disagree with some of the nihilism here: you do not need to put your data in the butt. Butt services are “free,” but only because you’re the product.  If you think you have nothing to hide and privacy is dead and irrelevant, you are both failing to keep up with the news and extremely unimaginative. You think you have no enemies?  Nobody would do you wrong for the lulz?  Nobody who would exploit information leaks for social engineering to rip you off?

Use butt services only when the function the service provides is predicated on a network effect (like Facebook) or simply can’t be replicated with individual scale resources (Google Search).  Individuals can reduce the risk of being a collateral target by setting up their own services like an email server, web server, chat server, file server, drop-box style server, etc. on their own hardware with minimal expertise (and the internet is actually full of really good and expert help if you make an honest attempt to try), or use a local ISP instead of relying on a global giant that is a global target.

Email Can be Both Secure AND Convenient:

But there’s something this Sony attack has made even more plain: eMail security is bad.  Not every company uses the least insecure email system possible and basically invites hackers to a data smorgasborg like Sony did by using outlook (I mean seriously, they can’t afford an IT guy who’s expertise extends beyond point-n-click?  Though frankly the most disappointing deployment of outlook is by MIT’s IT staff.  WTF?).

As lame as that is, email systems in general suffer from an easily remediated flaw: email is stored on the server in plain text which means that as soon as someone gets access to the email server, which is by necessity of function always globally network accessible, all historical mail is there for the taking.

Companies institute deletion policies where exposed correspondence is minimized by auto-deleting mail after a relatively short period, typically about as short as possible while still, more or less, enabling people to do their jobs.  This forced amnesia is a somewhat pathetic and destructive solution to what is otherwise an excellent historical resource: it is as useful to the employees as to hackers to have access to historical records and forced deletion is no more than self-mutilation to become a less attractive target.

It is trivial to create a much more secure environment with no meaningful loss of utility with just a few simple steps.

Proposal to Encrypt eMail at Rest:

I wrote in detail about this recently.  I realize it is a TLDR article, but as everyone’s wound up about Sony, a summary might serve as a lead-in for the more actively procrastinating. With a few very simple fixes to email clients (which could be implemented with a plug-in) and to email servers (which can be implemented via mail scripting like procmail or amavis), email servers can be genuinely secure against data theft.  These fixes don’t exist yet, but the two critical but trivial changes are:

Step One: Server Fix

  • Your mail server will have your public key on it (which is not a security risk) and use it to encrypt every message before delivering it to your mailbox if it didn’t come in already encrypted.

This means all the mail on the sever is encrypted as soon as it arrives and if someone hacks in, the store of messages is unreadable.  Maybe a clever hacker can install a program to exfiltrate incoming messages before they get encrypted, but doing this without being detected is very difficult and time consuming.  Grabbing an .ost file off some lame Windows server is trivial. I don’t mean to engage in victim blaming, but seriously, if you don’t want to get hacked, don’t go out wearing Microsoft.

Encrypting all mail on arrival is great security, but it also means that your inbox is encrypted and as current email clients decrypt your mail for viewing, but then “forget” the decrypted contents, encrypted messages are slower to view than unencrypted ones and, most crippling of all, you can’t search your encrypted mail.  This makes encrypted mail unusable, which is why nobody uses it after decades. This unusability is a tragic and pointless design flaw that originated to mitigate what was then, apparently, a sore spot with one of Phil’s friends who’s wife had read his correspondence with another woman and divorce ensued; protecting the contents of email from client-side snooping has ever since been perceived as critical.1I remember this anecdote from an early 1990’s version of PGP.  I may be mis-remembering it as the closest reference I can find is this FAQ:

It was a well-intentioned design constraint and has become a core canon of the GPG community, but is wrong-headed on multiple counts:

  1. An intimate partner is unlikely to need the contents of the messages to reach sufficient confidence in distrust: the presence of encrypted messages from a suspected paramour would be more than sufficient cause for a confrontation.
  2. It breaks far more frequent use such as business correspondence where operational efficiency is entirely predicated on content search which doesn’t work when the contents are encrypted.
  3. Most email compromises happen at the server, not at the client.
  4. Everyone seems to trust butt companies to keep their affairs private, much to the never-ending lulz of such companies.
  5. Substantive classes of client compromises, particularly targeted ones, capture keystrokes from the client, meaning if the legitimate user has access to the content of the messages, so too does the hacker, so the inconvenience of locally encrypted mail stores gains almost nothing.
  6. Server attacks are invisible to most users and most users can’t do anything about them.  Users, like Sony’s employees, are passive victims of sysadmin failures. Client security failures are the user’s own damn fault and the user can do something about them like encrypting the local storage of their device which protects their email and all their other sensitive and critical selfies, sexts, purchase records, and business correspondence at the same time.
  7. If you’re personally targeted at the client side, that some of your messages are encrypted provides very little additional security: the attacker will merely force you to reveal the keys.

Step Two: Client Fix

  • Your mail clients will decrypt your mail automatically and create local stores of unencrypted messages on your local devices.

If you’ve used GPG, you probably can’t access any mail you got more than a few days ago; it is dead to you because it is encrypted.  I’ve said before this makes it as useless as an ephemeral key encrypted chat but without the security of an ephemeral key in the event somebody is willing to force you to reveal your key and is interested enough to go through your encrypted data looking for something.  They’ll get it if they want it that bad, but you won’t be bothered.

But by storing mail decrypted locally and by decrypting mail as it is downloaded from the server, the user gets the benefit of “end-to-end encryption” without any of the hassles.

GPG-encrypted mail would work a lot more like an OTR encrypted chat.  You don’t get a message from OTR that reads “This chat message is encrypted, do you want to decrypt it?  Enter your password” every time you get a new chat, nor does the thread get re-encrypted as soon as you type something, requiring you to reenter your key to review any previous chat message.  That’d be idiotic.  But that’s what email does now.

Adoption Matters

These two simple changes would mean that server-side mail stores are secure, but just as easy to use and as accessible to clients as they are now.  Your local device security, as it is now, would be up to you.  You should encrypt your hard disk and use strong passwords because sooner or later your personal device will be lost or stolen and you don’t want all that stuff published all over the internet, whether it comes from your mail folder or your DCIM folder.

It doesn’t solve a targeted attack against your local device, but you’ll always be vulnerable to that and pretending that storing your encrypted email on your encrypted device in an encrypted form adds security is false security that has the unfortunate side effect of reducing usability and thus retarding adoption of real security.

If we did this, all of our email will be encrypted, which means there’s no additional hassle to getting mail that was encrypted with your GPG key by the sender (rather than on the server).  The way it works now, GPG is annoying enough to warrant asking people not to send encrypted mail unless they have to, which tags that mail as worth encrypting to anyone who cares.  By eliminating the disincentive, universally end-to-end encrypted email would become possible.

A few other minor enhancements that would help to really make end-to-end, universally encrypted email the norm include:

  • Update mail clients to prompt for key generation along with any new account (the only required option would be a password, which should be different from the server-log-in password since a hash of that has to be on the server and a hash crack of the account password would then permit decryption of the mail there, so UX programmers take note!)
  • Update address books, vcard, and LDAP servers so they expect a public key for each correspondent and complain if one isn’t provided or can’t be found.  An email address without a corresponding key should be flagged as problematic.
  • Corporate and hierarchical organizations should use a certificate authority-based key certification system, everyone else should use web-of-trust/perspectives style key verification, which can be easily automated to significantly reduce the risk of MitM attacks.

This is easy. It should have been done a long time ago.


Footnotes   [ + ]

1. I remember this anecdote from an early 1990’s version of PGP.  I may be mis-remembering it as the closest reference I can find is this FAQ:
Posted at 16:21:29 UTC

Category: FreeBSDPrivacySecuritytechnology

Speaker Build

Friday, November 28, 2014 

In December of 2002 (really, 2002, 12 years ago), I decided that the crappy former Sony self-amplified speakers with blown amplifiers that I had wired into my stereo as surround speakers really didn’t sound very good as they were, by then, 7 years old and the holes in the plastic housing where the adjustment knobs once protruded were covered by aging gaffers tape.

At least it was stylish black tape.

I saw on ebay a set of “Boston Acoustics” woofers and tweeters back in the time when ebay prices could be surprisingly good.  Boston Acoustics was a well-respected company at the time making fairly decent speakers.  36 woofers and 24 tweeters for $131 including shipping.  About 100 lbs of drivers.  And thus began the execution of a fun little project.


Design Phase: 2003-2011

I didn’t have enough data to design speaker enclosures around them, but about a year later (in 2003), I found this site, which had a process for calculating standard speaker properties with instruments I have (frequency generator, oscilloscope, etc.)  I used the weighted diaphragm method.

WOOFER: PN 304-1150001-00 22 JUL 2000
FS  = 58HZ
RE  = 3.04 OHMS
QMS = 1.629
QES = 0.26
QTS = 0.224
CMS = 0.001222
EBP = 177.8

TWEETER: PN 304-050001-00 16 OCT 2000
FS  = 269HZ
RE  = 3.29 OHMS
QMS = 5.66
QES = 1.838
QTS = 1.387
CMS = 0.0006
VAS = 0.0778 (LITERS)
EBP = 86.7


Awesome.  I could specify a cross over and begin designing a cabinet.  A few years went by…

In January of 2009 I found a good crossover at AllElectronics.  It was a half decent match and since it was designed for 8 ohm woofers, I could put two of my 4 ohm drivers in series and get to about the right impedance for better power handling (less risk of clipping at higher volumes and lower distortion as the driver travel is cut in half, split between the two).


Eventually I got around to calculating the enclosure parameters.  I’m not sure when I did that, but sometime between 2009 and 2011.  I found a site with a nice script for calculating a vented enclosure with dual woofers, just like I wanted and got the following parameters:


1" PVC PORT TUBE: OD = 2.68CM, ID = 2.1CM = 3.46 CM^2
PORT LENGTH = 10.48CM = 4.126"

WIDTH = 12.613 = 4.829"
HEIGHT = 20.408 = 7.82"
DEPTH = 7.795 = 3"

In 2011 I got around to designing the enclosure in CAD:

There was no way to fit the crossover inside the enclosure as the drivers have massive, magnetically shielded drivers, so they got mounted on the outside.  The speakers were designed for inside mounting (as opposed to flange mounting) so I opted to radius the opening to provide some horn-loading.

I also, over the course of the project, bought some necessary tools to be prepared for eventually doing the work: a nice Hitachi plunge router and a set of cheap router bits to form the radii and hole saws of the right size for the drivers and PVC port tubes.

Build Phase (2014)

This fall, Oct 9 2014, everything was ready and the time was right.  The drivers had aged just the appropriate 14 years since manufacture and were in the peak of their flavor.

I started by cutting down some PVC tubes to make the speaker ports and converting some PVC caps into the tweeter enclosure.  My first experiment with recycled shelf wood for the tweeter mounting plate failed: the walls got a bit thin and it was clear that decent plywood would make life easier.  I used the shelf wood for the rest of the speaker: it was salvaged from my building, which was built in the 1930s and is probably almost 100 years old.  The plywood came with the building as well, but was from the woodworker who owned it before me.

I got to use my router after so many years of contemplation to shape the faceplates, fabricated from some fairly nice A-grade plywood I had lying around.

Once I got the boxes glued up, I installed the wiring and soldered the drivers in.  The wood parts were glued together with waterproof glue while the tweeters and plastic parts were installed with two component clear epoxy.  The low frequency drivers had screw mounting holes, so I used those in case I have to replace them, you know, from cranking the tunage.

I lightly sanded the wood to preserve the salvage wood character (actually no power sander and after 12 years, I wasn’t going to sand my way to clean wood by hand) then treated them with some polyurethane I found left behind by the woodworker that owned the building before I did.  So that was at least 18 years old.  At least.

I supported the speakers over the edge of the table to align the drivers in the holes from below.

The finished assembly looked more or less like I predicted:


The speakers sound objectively quite nice, but I was curious about the frequency response.  To test them I used the pink noise generator in Audacity to generate 5.1 6 channel pink noise files which I copied over to the HTPC to play back through my amp.  This introduces the amp’s frequency response, which is unlikely to be particularly good, and room characteristics, which are certainly not anechoic.

Then I recorded the results per speaker on a 24/96 Tascam DR-2d recorder, which also introduces some frequency response issues, and imported the audio files back into Audacity (and the original pink noise file), plotted the spectrum with 65536 poles, and exported the text files into excel for analysis.

Audacity’s pink noise looks like this:


It’s pretty good – a bit off plan below 10 Hz and the random noise gets a bit wider as the frequency increases, but it is pretty much what it should be.

First, I tested one of my vintage ADS L980 studio monitors.  I bought my L980s in high school in about 1984 and have used them ever since.  In college I blew a few drivers (you know, cranking tunage) but they were all replaced with OEM drivers at the Tweeter store (New England memories).  They haven’t been used very hard since, but the testing process uncovered damage to one of my tweeters, which I fixed before proceeding.

ADS L980 Spectrum

The ADS L980 has very solid response in the low frequency end with a nicely manufactured 12″ woofer and good high end with their fancy woven tweeter.  A 3 way speaker, there are inevitably some complexities to the frequency response.

I also tested my Klipsch KSC-C1 Center Channel speaker (purchased in 2002 on ebay for $44.10) to see what that looked like:

It isn’t too bad, but clearly weaker in the low frequency, despite moderate sized dual woofers and with a bit of a spike in the high frequency that maybe is designed in for TV and is perhaps just an artifact of the horn loaded tweeter. It is a two way design and so has a fairly smooth frequency response in the mid-range, which is good for the voice program that a center speaker mostly carries.

And how about those new ones?

New Speaker Spectrum

Well… not great, a little more variability than one would hope, and (of course) weak below about 100Hz.  I’m a little surprised the tweeters aren’t a little stronger over about 15kHz, though while that might have stood out to me in 1984, it doesn’t now.  Overall the response is quite good for relatively inexpensive drivers, the low frequency response, in particular, is far better than I expected given the small drivers.  The high frequency is a bit spiky, but quite acceptable sounding.

And they sound far, far better than the poor hacked apart Sony speakers they replaced.

Raw Data

The drawings I fabricated from and the raw data from my tests are in the files linked below:

Speaker Design Files (pdf)

Pink Noise Tests (xlsx)

Posted at 21:05:03 UTC

Category: AudioFabricationHowTophototechnology

Keep the Pitchforks Sharp

Tuesday, January 24, 2012 

While David Pogue’s opinion piece “Put Down the Pitchforks” makes a valid point about the alliance of varied views on the utility and validity of copyright that have come together to oppose SOPA/PIPA, the differences are more subtle than his language indicates.

Everyone, even those characterized (somewhat fairly) as the “we want our illegal movies” crowd, is horrified that the United States would contemplate outright censorship of the web à la North Korea or Iran, something we actively fight quite vigorously, and with USAID and State Department support, to ensure that dissidents can circumvent similar blocking schemes.

There is no way to fix the language of the bills to rule out those abuses. Universal filling a flagrantly illegal DMCA takedown request with YouTube to censor the MegaUploads advertisement video, the pernicious use of malicious prosecution by the RIAA, and the recent MPAA/Chris Dodd bribery flap all demonstrate incontrovertibly how the entertainment industry has been utterly shameless to date and there is no basis for the belief that they would voluntarily refrain from an aggressive and likely illegal extension of whatever new powers they are offered. If anything, we need stronger legislation to discourage the current abuse of litigation and take-down powers.

Thus everyone, including those that believe that copyright needs to be extended (again, further), recognizes that the premise of SOPA/PIPA—that parts of the international internet have to be blocked in the US—are fundamentally flawed and cannot be repaired.

The differentiation between the “ignorant mechanism” and “ignorant goal” camps is, however, unfairly characterized by Pogue when he draws an analogy to shoplifting. Copyright is not a property right—it is a privilege that is granted by we the people, an exchange where we the people voluntarily relinquish our right to copy, and we gift the inventor with a temporary monopoly as an incentive to promote the progress of science and the useful arts.

It is not “stealing” to copy a movie; it may be illegal, but it is not stealing. There is no legal basis to consider such an act theft—not in natural law, not in “denial of utility.”

“If nature has made any one thing less susceptible than all others of exclusive property, it is the action of the thinking power called an idea, which an individual may exclusively possess as long as he keeps it to himself; but the moment it is divulged, it forces itself into the possession of every one, and the receiver cannot dispossess himself of it.”

– Thomas Jefferson, 1813

(A letter that should be read in its entirety by anyone electing to weigh in on copyright.)

The basis and purpose of copyright is codified in the constitution: it is an agreement between we the people and inventors to promote the progress of science and the useful arts, it is neither a property right nor a human right. If any copyright legislation fails to advance the cause of promoting the progress of science and the useful arts it is simply prima facia unconstitutional. And not a single extension of copyright law, back to and including the Sony Bono Copyright Extension Act, has even bothered to pay lip service to the obligation to promote the progress of science and the useful arts.

The problem is that these bills retard progress by hampering important and economically relevant industries for economically irrelevant ones (regardless of how nostalgic they might be). It is fair, still, to frame copyright protections and copyright modifications with respect to the expected actual net contribution to the progress of science and the useful arts, as the constitution requires. It is unlikely that such an analysis would favor complete abolition of copyright but it is clear that only a mechanism closer to the patent model makes sense: a very limited and carefully regulated temporary monopoly granted to inventors and creators in return for fully contributing their efforts to the public domain promptly thereafter.

(Edited and enhanced by Carolyn Anhalt)

Posted at 14:42:48 UTC

Category: politicstechnology

kitty says whut

Sunday, January 30, 2011 

Sony Nex5 ISO 12,800 dim indoor lighting.

Posted at 00:31:16 UTC

Category: catsphoto