January 19, 2012 // 12:27 am
- Today PlayStation 3 hacker KaKaRoToKS
has posted a status update on the PS3 4.0 Homebrew Enabler (HEN), which comes just six weeks since the previous
confirmation that it indeed works on Sony's latest Firmware version.
To quote: Here’s a “quick” status update on the 4.00 HEN (Homebrew ENabler) for PS3.
Following my clarifications from almost 2 months ago here
, there has been a lot of progress. We have not been slacking off, we’re a group of about 10 developers working together for the last 2 months, for sometimes 15 hours everyday in order to bring back homebrew support to the latest version of the PS3.
There are three major parts to the HEN, first, getting the packages to install on the PS3, that part is done, completed, tested, debugged, etc.. the second part is to get the apps to run, that one still has major issues... the last part is something I will not discuss for now (it’s a surprise) but it’s about 60% to 70% done (and it has nothing to do with peek&poke and has nothing to do with backup managers or anything like that. This is and will stay a piracy-free solution for the PS3).
Now, running apps is the biggest challenge that we’ve been working on for the past 2 months. As some of you know, if you’ve been following me on Twitter, we originally had hoped for Mathieulh to give us the “NPDRM hash algorithm” that was necessary to run the apps, but he was reluctant, he kept doing his usual whore so people would kiss his feet (or something else) so he’d feel good about himself. But in the end, he said that he refuses to give us the needed “NPDRM hash algorithm” to make it work... So what I initially thought would be “this will be released next week” ended up taking a lot more time than expected, and we’re still nowhere near ready to make it work.
Mathieulh kept tossing his usual “riddles” which he thinks are “very helpful for those who have a brain”, and which pisses off anyone who actually does... so he told us that the solution to all our problems was to look in appldr of the 3.56 firmware.. and that it was something lv1 was sending appldr which made the “hash check” verified or not… so we spent one month and a lot of sweat and after killing a few of our brain cells out of exhaustion, we finally concluded that it was all bullsht. After one month of reading assembly code and checking and double-checking our results, we finally were able to confirm that that hash algorithm was NOT in the 3.56 firmware like he told us (at all).
He said that it was an AES OMAC hash, but after tracking all the uses of the OMAC functions in appldr, we found that it was not used for the “hash”… he then said “oh, I meant HMAC”, so we do that again and again come up with the same conclusion, then we’re sure it’s not in appldr, and then he says “ah no, it’s in lv1”.. have a look for yourself to what he decided to write: ps3devwiki.com/index.php?title=Talk:KaKaRoTo_Kind_of_%C2%B4Jailbreak%C2%B4
That happened after the huge twitter fight I had with him for being his usual arrogant self and claiming that he “shared” something (For your information, the code that he shared was not his own, I have proof of that too (can’t show you the proof because even if I don’t respect him, I gave him my word to not share what he gave me, and I respect my word) since he forgot to remove the name of the original developer from one of the files... also it was completely useless and was not used at all, just made me waste a day reading the crappy undocumented code. So why is he still trying to force his “advice” through these riddles even after we had that fight? Well to sabotage us and make us lose all those months of hard work!
So anyways, we had all accepted that Mathieulh was full of sht (we knew before, but we gave him the benefit of the doubt) and decided to continue working without considering any of his useless riddles. So we then tried to exploit/decrypt the 3.60+ firmware in order to get the algorithm from there.
Now, a few more weeks later, we finally have succeeded in fully understanding that missing piece from the “NPDRM hash algorithm”, and here it is for everyone’s pleasure with some prerequisite explanation:
A game on the PS3 is an executable file in a format called a “SELF“file (kind of like .exe on windows), those “self” files are cryptographically signed and encrypted.. For PSN games (games that do not run from a Blu-ray disc), they need to have an additional security layer called “NPDRM”. So a “NPDRM self” is basically an executable that is encrypted and signed, then re-encrypted again with some additional information. On 3.55 and lower, we were able to encrypt and sign our own self files so they would look like original (made by sony) “NPDRM self” files, and the PS3 would run them without problem.
However, it wasn’t really like an original file.. a real NPDRM self file had some additional information that the PS3 simply ignored, it did not check for that information, so we could put anything in it, and it worked. Since the 3.60 version, the PS3 now also validates this additional information, so it can now differentiate between NPDRM self files created by Sony and the ones that we create ourselves for homebrew. That’s the “NPDRM hash algorithm” that we have been trying to figure out, because once we can duplicate that information in the proper manner, then the PS3 will again think that those files are authentic and will let us play them.
Another important point to explain, I said a few times that the files are “signed”.. this means that there is an “ECDSA signature” in the file which the PS3 can verify. The ECDSA signature is something that allows the PS3 to verify if the file has been modified or not.. it is easy to validate the signature, but impossible to create one without having access to the “private keys” (think of it like a real signature, you can see your dad’s signature and recognize it, but you can’t sign it exactly like him, and you can recognize if your brother tried to forge his signature). So how were we able to sign the self files that were properly authenticated on 3.55?
That’s because this “ECDSA signature” is just a very complicated mathematical equation (my head still hurts trying to fully understand it, but I might blog about it in the future and try to explain it in simple terms if people are interested), and one very important part of this mathematical equation is that you need to use a random number to generate the signature, but Sony had failed and used the same number every time.. by doing that, it was easy to just find the private key (which allows us to forge perfectly the signature) by doing some mathematical equation on it. So to summarize, a “signed file” is a file which is digitally signed with an “ECDSA signature” that cannot be forged, unless you have the “private key” for it, which is impossible to obtain usually, but we were able to obtain it because Sony failed in implementing it properly.
Now, back on topic.. so what is this missing “NPDRM hash algorithm” that we need? well it turns out that the “NPDRM self” has a second signature, so it’s a “encrypted and signed self file” with an additional layer of security (the NPDRM layer) which re-encrypts it and re-signs it again. That second signature was not verified in 3.55 and is now verified since the 3.60 version of the PS3 firmware.
One important thing to note is that Sony did NOT make the same mistake with this signature, they always used a random number, so it it technically impossible to figure out the private key for it. To be more exact, this is the exact same case as the .pkg packages you install on the PS3, you need to patch the firmware (making it CFW) so that those .pkg files can be installed, and that’s because the .pkg files are signed with an ECDSA signature for which no one was able to get the private key. That’s why we call them “pseudo-retail packages” or “unsigned packages”.
The signature on the NPDRM self file uses the exact same ECDSA curve and the same key as the one used in PS3 .pkg files, so no one has (or could have) the private key for it. What this means is that, even though we finally figured out the missing piece and we now know how the NPDRM self is built, we simply cannot duplicate it.
The reason we wasted 2 months on this is because Mathieulh lied by saying that he can do it.. remember when the 4.0 was out and I said “I can confirm that my method still works” then he also confirmed that his “NPDRM hash algorithm” still works too? well he didn’t do anything to confirm, he just lied about it because there is no way that he could have verified it because he doesn’t have the private key.
I said I will provide proof of the lies that Mathieulh gave us, so here they are: he said it’s in 3.56, that was a lie, he said it’s an AES OMAC, that was a lie, he said it’s an HMAC, that was a lie, he said it’s in appldr, that was a lie, he said it’s in lv1, that was a lie, he said that he can do it, that was a lie, he said that “it takes one hour to figure it out if you have a brain”, that was a lie, he said that he verified it to work on 4.0, that was a lie, he said that he had the algorithm/keys, that was a lie, he said that once we know the algorithm used, we can reproduce it, that was a lie, he kept referring to it as “the hash”, that was wrong.
The proof ? It’s an ECDSA signature, it’s not a hash (two very different terms for different things), it was verified by vsh.self, it was not in lv2, or lv1, or appldr, and the private key is unaccessible, so there is no way he could build his own NPDRM self files. Now you know the real reason why he refused to “share” what he had.. it’s because he didn’t have it...
So why do all this? was it because his arrogance didn’t allow him to admit not knowing something? or was it because he wanted to make us lose all this time? To me, it looks like pure sabotage, it was misleading information to steer us away from the real part of the code that holds the solution... That is of course, if we are kind enough to assume that he knew what/where it was in the first place. In the end, he wasn’t smart enough to only lie about things that we could not verify.. now we know (we always knew, but now we have proof to back it) that he’s a liar, and I do not think that anyone will believe his lies anymore.
Enough talking about liars and drama queens, back to the 4.0 HEN solution... so what next? well, we now know that we can’t sign the file, so we can’t run our apps on 3.60+ (it can work on 3.56 though). What we will do is look for a different way, a completely new exploit that would allow the files we install to actual run on the PS3. We will also be looking for possible “signature collisions” and for that we will need the help of the community, hopefully there is a collision (same random number used twice) which will allow us to calculate the private key, and if that happens, then we can move forward with a release.
When will the “jailbreak” be released? If I knew, I’d tell you, but I don’t know.. I would have said in last November, then December, then before Christmas, then before new year, etc... but as you can see, it’s impossible to predict what we will find.. we might get lucky and have it ready in a couple of days, or we may not and it will not be ready for another couple of months.. so all you need to do is : BE PATIENT (and please stop asking me about an estimated release date)!
I would like to thank the team who helped on this task for all this time and who never got discouraged, and I’d like to thank an anonymous contributor who recently joined us and who was instrumental in figuring it all out. We all believe that freedom starts with knowledge, and that knowledge should be open and available to all, that is why we are sharing this information with the world. We got the confirmation (by finding the public key used and verifying the signatures) yesterday and since sharing this information will not help Sony in any way to block our efforts in a future release, we have decided to share it with you. We believe in transparency, we believe in openness, we believe in a free world, and we want you to be part of it.
If you want to know more about this ECDSA signature algorithm, read this interesting paper (engineering.purdue.edu/kak/compsec/NewLectures/Lecture14.pdf) that explains it in detail, and you can also watch Team Fail0verflow’s CCC presentation (youtube.com/watch?v=5E0DkoQjCmI) that first explained Sony’s mistake in their implementation, which made custom firmwares possible.
Thanks for reading,