Slashdot Mirror
HDCP Break Proven
zavyman writes: "I just noticed at Cryptome that the flaws in HDCP posted to Slashdot earlier this year, which one person refused to disclose due to possible threats from the DMCA, have been made public by different authors. Scott Crosby of Carnegie Mellon University, Ian Goldberg of Zero Knowledge Systems, and Robert Johnson, Dawn Song, and David Wagner of UC Berkeley have published a formal cryptanalysis of the High-bandwidth Digital Content Protection System that proves its fatal flaws. Interesting reading for those with some background with cryptanalysis."
Just in case the origonal authors' fears are justified, I've mirrored the page here [http://lookingglass.akardam.net/mirrored/hdcp-wea kness/hdcp111901.htm for the link wary].
Mirror early, mirror often.
Having a bit of formal training in Math, I'm just speechless. This is not crypto analisys, this is second semester of Algebra, Quiz question #2.
.. blech .. I do not know who designed this, neither I'm not sure if they even cared to independently evaluate it, but this is incredibly and incomprehensibly lame. It's like using XOR encryption or computing hash bytes multiplication.
Public/Private keys
3.243F6A8885A308D313
(This is the author of the slides, BTW)
Intel wanted a scheme that could be implemented in under 10,000 gates. IMHO, the designers were aware of the flaw, though not necessarily of the full impact of the flaw. Some of the attacks are subtle.
There were two versions posted on cryptome, the second (latex2html, much easier to read) omitted this statement the first version had:
h acks.html), and myself (www.cryptome.org/hdcp-weakness.htm). The last two have been available publically for 3 months and 3 weeks prior to Neils Ferguson's declaration. Neils declaration and the skylarov case were an eye-openeer for me and made fully realize what I had done, and what negative consequences I was in danger of experiencing.
`` The attacks on HDCP are neither complicated nor difficult. They are basic linear algebra. Thus, there have been at least 4 independent discoveries of these flaws. The four I know of are my co-authors, Neils Ferguson, Keith Irwin (http://www.angelfire.com/realm/keithirwin/HDCPAt
What wrathful gods one risks angering by a 20 minute straightforward application of 40 year old math. This was an accident, not a habit. Like other researchers, I do not want to be smited and thus do not expect to analyze any more such schemes as long as the DMCA exists in its current form.
(This statement is my own and does not represent the opinions of my co-authors.)''
So, for those of you who watch cryptome, I broke it there about 3 days after it was leaked, 6 months ago. Keith Irwin also put his observations up 3 months ago. All of this predates skylarov and ferguson.
So, this is only the official version of the break, the slides I presented 2 weeks ago.
I broke it over 6 months ago, go look at the cryptome archives, where its been sitting since May 9th.
:)
I know of at least 4 researchers who have independently discovered the flaws. (See my other slashdot post).
After Skylarov and Ferguson, I was reluctant to point out that my work had been sitting around on cryptome since May. I suspect Keith Irwin felt similarily.
Neils wasn't the first to go public or even second, though he did raise a wonderful stink.
ok sorry changed the URL due to misinformation
here's the proper URL
This is pretty basic, but for those who don't know, HDCP is the encryption scheme of choice for HDTV video signals. This is fairly huge news that it has been broken since all TV's and broadcasts in the US will supposedly eventually switch to the HDTV standard. Unless they pull a fast one and switch the standard (which would alienate everyone who has already bought expensive HDTV equipment), this means that DMCA or not, people are going to have guaranteed access to plaintext HDTV signals for as long as the standard is in use. Of course, I'm personally hoping that the DMCA is at least re-written, preferrably scuttled altogether.
OK, scenario for ya: I work in a small office (25 people) and one of them is a subject of an investigation. When you pick up the phone anywhere in our office, the phone system grabs the next free line. That means that the FBI will be listening to ALL CALLS into and out of our office because this person may be using that phone. The legislation does not limit this! There was a Senator (can't remember the name, can't find it on Google) who had wanted to add that the tap was not allowed to be monitored if the suspect was not on the phone at the time, but this got shot down.
Another question is how often does a suspect use a phone before it's wire-tapped? Should we expect all public to be tapped? If I throw a party and a friend-of-a-friend makes a call or two to order a pizza, should I wonder if my phone is now tapped?
Never never never smoke crack before geometry class!