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HDCP master key allegedly posted
- js4all 16y agoThe comments so far are just about HDCP, Blu-Ray and playback difficulties. The paste however contains the key matrix used to encrypt and decrypt the digital video signal. If this is valid, every transmission between a HDCP-secured playback device and the display can be decrypted, thus rendering every other encryption method, used in the playback chain, useless, including AACS and BD+. This is serious, because the keys for AACS can be revoked, if compromised. HDCP keys however can't be revoked.
- bdonlan 16y agoHDCP keys can be revoked. It just won't do any good - this matrix lets you create _new_ keys, just as valid as all pre-existing ones.
- nitrogen 16y agoIt doesn't completely render BD+ useless, as BD+ can be used to watermark the video signal according to the player model (and hypothetically other variables, like location, IP address, or player serial number). So, to avoid identification, pirates would need to crack BD+, or combine the output from multiple players to obscure the watermarking. Another problem with cracking the transport instead of the storage medium, is that to rip from HDMI you have to play the movie at normal speed, while ripping straight from disc can be done much faster.
- js4all 16y agoI agree with the second point. Regarding on-the-fly watermarking, I see the hypothetical use, but current watermarking algorithms are to complex for BD+. An interesting idea though.
- m0nastic 16y agoFor those curious as to what this entails, the Wikipedia article: http://en.wikipedia.org/wiki/Hdcp#Cryptanalysis http://en.wikipedia.org/wiki/Hdcp#Cryptanalysis Does a pretty good job explaining. For those not quite that curious, if you've ever tried to watch a Blu-Ray movie on your computer, and gotten an error about it being restricted from playing back on your display; there's a good chance that is because of HDCP. If this is true (and there isn't really a good reason to believe that it isn't), this is pretty bad news for the content industry.
- oomkiller 16y ago...And pretty good news for everyone else!
- teej 16y agoAre you kidding? This is -awesome-. My single worst experience with iTunes was when I took the dive and spent that extra dollar to rent an HD movie. Just to find out a $5 movie on my $500 Mac Mini won't play on my $1,000 TV. I haven't made a -single- Apple purchase since then. That's how badly HDCP pissed me off.
- jrockway 16y agoYeah. This is a problem that I've never had with pirated movies. 1020p Blu-Ray? Plays great under Linux on my pre-HDCP LCD and TV. And it was free. What problem was HDCP trying to solve, again?
- lhnz 16y agoThe problem of people not getting money.
- ZeroGravitas 16y agoWhich it failed spectacularly at by a) not doing anything to curb piracy, and b) pissing off actual consumers so much they'd rather pirate, c) being such "a bag of hurt" that it didn't get added to Apple's computers.
- Blunt 16y agoand c) the dillusion that there exists lost sales because a torrent of said flick is available now...
- jrockway 16y agoNo, I think the consumer electronics companies made a lot of money off of this. That Big Content mandated it was even better for them. Selling a 50 cent piece of wire for $80 is a much better business model than making a movie and getting people to buy it, after all.
- deleted 16y ago[deleted]
- seldo 16y agoBlu-Ray on Windows is the single most user-hostile computing experience I've ever had. I stopped buying/renting blu-ray movies because I didn't feel like rebooting 3 times every time I wanted to play a disc, with the software treating me like a criminal the whole time.
- thehodge 16y agoI bought my first Blue-Ray the other day and the experience was terrible, I put the disk in and nothing happened.. I tried to play it in windows media center, no ball.. not in VLC.. there was no player included on the disk. I had to download a 300meg trial of PowerDVD just to play a film I'd already paid for (I also had to update my graphics card for some reason, the computer had been playing HD content for months without needing that). That will be the last Blue-Ray disk I buy..
- viraptor 16y ago> That will be the last Blue-Ray disk I buy.. I wouldn't be so sure. This is exactly the experience I got in the first year of DVDs being available. (although the player was a bit lighter ;) ) After some time we got proper software for Windows and after that, there was DeCSS. Just give it time. If there is useful content on Blue-Ray, people will use it and the experience will improve.
- sofuture 16y agoRight, the experience of being treated like a criminal will improve. Their shackled product won't.
- viraptor 16y agoOn one hand-side - yes, you're right. On the other - right now you have a choice of not seeing the movie at all, or maybe seeing it correctly in the next month thanks to this key. One step at a time. Also, there's a whole industry around copy-protection which won't go away in one day. Pretty much the best we can do right now, is make is obsolete by proving DRM is useless, while they will try to prove otherwise. DVD-s right now are a nice compromise where they did their job™, and we get the content as if it was not locked. (of course you still cannot skip the intros on "official players", but that's just an education issue - for example mplayer can play the movie itself without the added marketing crap)
- ra 16y agoAnd so the DRM Cold War continues.
- audidude 16y agoFor some reason I don't think that will make such a good t-shirt this time around.
- daychilde 16y agoMaybe it'd work better for folks like me who shop at big&tall stores... We have the perfect body for this t-shirt. Finally, all my McDonald's days are about to pay off!
- flannell 16y agoI've had nothing but trouble with HDCP. I've used HDMI matrix switches to transport a video signal around the house. 40% of the time I get the HD snowstorm so have to reboot the TV to attempt a second handshake. This gives a low Wife Approval Factor. I believe they should stop torturing the paying punters, like me, and just be happy with the majority who pay and not the minority that don't. Also, before someone mentions the x billion lost per year, I doubt maybe the 100,000 that downloaded 'The Bounter Hunter' would of seriously bought it.
- reduxredacted 16y agoAlso, before someone mentions the x billion lost per year It's bizarre. Imagine a job where my customer complains about how ineffective my product is yet continues to shovel money at me. Wait, even worse, my product makes their customers miserable and yet they still shovel money at me. It sort of sounds like the business model of a crack dealer.
- joeyo 16y agoOr a monopolist.
- andybak 16y agoDon't they have a contingency for this? I thought they could update the DRM code in devices with a new key or some such thing.
- nash 16y agoI believe the update of keys relies on the secrecy of the master key, which is never released in a device. Hence the master key pretty much kills it all.
- dfox 16y agoHDCP key exchange is very weird cryptosystem. Usually you generate some essentially random private key and trivially derive public key from it. In HDCP, it works other way around: central authority has ability to convert (random) public keys to private keys using some secret information (purpotedly this matrix). Motivation of this design is twofold: (a) actual hardware implementation is simple and (b) this central authority can impose varios policies about who gets private keys. On the other hand both these points make this cryptosystem very weak. Therefore, this matrix may not even be leaked, but somebody might reconstruct it from relatively small number (I don't remember exact required number, but i recollect that it is at most thousands) of keypairs recovered from devices in circulation. By the way similar mode of deployment was once recommended for RSA (having shared modulus whose factorization is known to central authority), but it is long known to be insecure (for RSA). I don't know of any non-HDCP related analysis of public key cryptography based on similar approach as HDCP (vector summing or matrix multiplication, depending on viewpoint), which probably means that it is very well known to be insecure. Edit: and for the key update: you would have to update all deployed keys simultaneously, which is probably impossible. Moreover HDCP does not even specify any kind of infrastructure to accomplish this.
- tlrobinson 16y agoI recall hearing ~50 keypairs would be required to reconstruct this matrix thing. Certainly there are more than 50 HDCP devices (manufacturers?)
- Maakuth 16y agoYes, "allegedly". This is definitely good news if it's the real thing. I wonder how long does it take to confirm it's authenticity.
- js2 16y agoHere's a paper discussing how this key could have been derived: http://www.cs.rice.edu/~scrosby/pubs/hdcppaper.ps http://www.cs.rice.edu/~scrosby/pubs/hdcppaper.ps http://www.cypherpunks.ca/~iang/pubs/hdcp-drm01.pdf http://www.cypherpunks.ca/~iang/pubs/hdcp-drm01.pdf Here's the fun bit: "We observe that attackers can exploit a well-known cryptographic design mistake: the shared secret generation is entirely linear. The attack only needs 40 public/private key pairs such that the public key pairs span M ⊂ (Z/256Z)40, the module generated by all public keys. Since HDCP devices divulge their public keys freely, one can easily test whether a set of 40 devices have public keys spanning M before expending the effort to extract their private keys. With these keys, the authority’s secret can be recovered in only a few seconds on any desktop computer." Edited to add the next paragraph (paper was published in 2001): "The consequence of these flaws is that, after recovering the private keys of 40 devices, we can attack every other interoperable HDCP device in existence: we can decrypt eavesdropped communications, spoof the identity of other devices, and even forge new device keys as though we were the trusted center. Note that this allows us to bypass any revocation list or “blacklisting”: such mechanisms are rendered completely ineffective by these flaws in HDCP. Therefore we recommend that the current HDCP cryptosystem should be abandoned and replaced with standard cryptographic primitives."
- nitrogen 16y agoTherefore we recommend that the current HDCP cryptosystem should be abandoned and replaced with standard cryptographic primitives. So does this mean that all new equipment will quickly switch to DisplayPort, necessitating another round of TV/monitor upgrades? Or will the HDMI organization add DPCP (AES) to the HDMI standard? [Edit: it was mentioned elsewhere* in the thread that HDCP 2.0 uses AES] * http://news.ycombinator.com/item?id=1691794 http://news.ycombinator.com/item?id=1691794
- yock 16y agoI can't believe people are willing to assign any credibility to an anonymous dump of hex to pastebin.
- mechanical_fish 16y agoThat's the wonderful thing about math. You can verify its correctness without reference to anybody's reputation or personal opinion. Indeed, that's pretty much the definition of math.
- yock 16y agoOf course you can verify if it's valid, but that's remarkably short of what's being claimed here. Lots of folks here are talking as if this is the end of HDTV DRM. I'm simply advocating that someone with the means actually test it before we start singing "Ding Dong The Witch is Dead."
- reduxredacted 16y agoCatch-22. Credibility is less because it was posted anonymously as a dump of hex to paste-bin, therefore eliminating any authority that would come if this person was a well-known security researcher. If the author had credibility and wanted to use his/her reputation to make the post more credible, he'd have the pleasure of a herd of lawyers and law enforcement at his door, assuming that he lives in a country with anti-circumvention laws. So his only choice is to keep it to himself or post anonymously, taking away any credibility that comes with authority in a subject. Regardless, someone will test this soon enough and determine if this non-credible post is credible or just a creative bunch of social engineering. That it's garnered this much attention this quickly (take a look at your major social news sites ... and tech blogs) should scare industry insiders. The mere HOPE that some random posting on pastebin would topple HDCP and bring a possible end to device interoperability would get this much attention truly highlights what a dismal mess HDCP is. If it's The Real Thing(tm), we'll know when the master key is used to generate a random device key and 80% of the time the signal is decrypted properly without having to turn both devices off and back on. And if it is true, I hope our friend that posted it took some pretty serious precautions to protect his own anonymity.
- bcl 16y agoHas anyone verified that this actually works?
- wmf 16y agoTime to light up the Bunnie signal.
- reduxredacted 16y agoWorth noting (again, assuming this is credible): Version 2.0 of HDCP is likely not affected. According to their FAQ: http://www.digital-cp.com/faqs http://www.digital-cp.com/faqs "HDCP revision 2.0 uses industry-standard public-key RSA authentication and AES 128 encryption. It also supports protection of compressed content, making it feasible to use relatively slow 50 to 200 Mbps interfaces." ... and ... "HDCP 1.x technology offers protection for uncompressed content transmitted over several common wired interfaces including DVI, HDMI and DisplayPort. HDCP revision 2.0 adds strengthened encryption..."
- wmf 16y ago"The wireless interfaces which utilize HDCP revision 2.0 so far include: Digital Interface for Video and Audio (DiiVA), NetHD, Wireless Home Digital Interface (WHDI), and Wireless HD (WiHD)." In other words, no equipment that anyone has.
- b3b0p 16y agoComments keep mentioning Blu-ray playback, but it's referring to HDCP. That's the connection between devices I thought? I don't think this does anything for Blu-ray as it has it's own encryption scheme. Edit: Oops, I see someone mentioned this already. Missed that comment.
- uuoc 16y agoThe Cory Doctorow info-graphic is quite appropriate here: http://boingboing.net/2010/02/18/infographic-buying-d.html http://boingboing.net/2010/02/18/infographic-buying-d.html
- toodoo 16y agoAnd here come the T-Shirts http://www.cafepress.com/HDCP http://www.cafepress.com/HDCP
- nitrogen 16y agoI was a minor participant in the tvtime project years ago. HDMI and HDCP came around and made that kind of thing highly improbable for HD content. CPUs and GPUs are now at speeds that make advanced HD video manipulation practical. I hope this HDCP crack, if verified, makes a tvtime-like application for HDMI video possible. Better yet, a PC-based realtime compositing and overlay system, requiring only a $100 GeForce GPU and HDMI capture cards.