forums.ps2dev.org

TerryMathews · Joined: 31 Mar 2005 Posts: 19

In my other thread (which was locked... I don't think it's useless since PS2DIS doesn't currently decode PSP files because they're encrpted or compressed, but whatever) I decoded some of the R4000 opcodes into hex and binary. As near as I could tell, there was only one that took no arguments: sync. It's 0x0000000F.

Now, I reckon based on the description of sync in the R4000 user's manual, there ought to be at least one place in the firmware flasher and several in the actual firmware that utilize that opcode; yet it doesn't appear at all in DATA.PSP or DATA.PSAR from the Jap 1.5 firmware PBP.

I don't know much about AES, and don't pretend to. That said, does AES shift characters based on the key in a reliable manner? What I mean is, would there be a pattern that we could look for based on what we know the input was?

If this is a stupid idea, lock it up too. It's the only thing I can come up with that doesn't involve brute-forcing the key.

Guest · Posted: Mon Apr 04, 2005 1:00 pm Post subject:

No, that would be too easy, and what you are describing is still akin to brute forcing, the searching for known patterns.

None of the cryptos involved are likely to be able to be attacked directly. Only 3-letter agencies and Ph.D. Math cryptographers with too much time and research dollars on their hands can afford to lead such efforts (and that includes famous successful efforts in the past announced on the internet).

Besides, do not think for one moment there won't be a severe reaction from Sony if we are able to decrypt intellectual property meant to remain unseen. Not that Sony needs to worry that much, of course. But there might be some lines we need to define so that we don't cross them, and that can be hard to do.

For example, MagicGate has always been hands-off. We were able to homebrew without it and there was no need to touch things that were better off being left alone. Here, we cannot yet homebrew on the PSP, so people will grasp at anything. Still are there some rules we should define ?

TerryMathews · Joined: 31 Mar 2005 Posts: 19

blackdroid · Joined: 17 Jan 2004 Posts: 564 Location: Sweden

Yes your idea of finding opcode patterns is stupid, I suggest reading a good book on cryptography to understand why and when the idea of finding patterns in cryptographed streams was abandoned.

And as gorim said we are able to run code on the PS2 without having the key.

If you want more opcodes that takes no args, grep through the mips opcode table in a recent gcc source, you will find some more, like the ever present nop wich we all love and adore.
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TerryMathews · Joined: 31 Mar 2005 Posts: 19

boomint · Joined: 13 Apr 2004 Posts: 80 Location: Sheffield, UK

Some people seem hell bent on annoying others, especially those that have some inkling of what may be possible - small minded "geez what about this" posts annoy normal everyday readers of these forums....

Take it somewhere else! :)
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mrbrown · Joined: 17 Jan 2004 Posts: 1536

Shine · Joined: 03 Dec 2004 Posts: 728 Location: Germany

mc · Joined: 12 Jan 2005 Posts: 212 Location: Link�ping

I expect the "utility applets" are stuff like the screen you get when pressing HOME. As far as could be seen from the SFO experiments, the XMB interface is a normal application running in user space, and not part of the 8MB kernel.
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kry.sys · Joined: 16 Mar 2005 Posts: 82

I think of XMB as a shell. utility applets are things like the numbered letter entry system and the game save and load. ... another popular utility applet is the web browser.

ichan · Joined: 03 Apr 2005 Posts: 7

I've read in many places that breaking the encryption is not an option. (not only because of difficulty, but due to wanting to avoid the wrath of Sony)... but why?? i just won't really get it. nothing else seems to be sacred, why this?

Guest · Posted: Thu Apr 07, 2005 12:06 pm Post subject:

ichan · Joined: 03 Apr 2005 Posts: 7

well, i don't even know what to say to that... point taken...

J.F. · Joined: 22 Feb 2004 Posts: 2906

It's a matter of trust. It's saying that we're just as serious about preventing the use of homebrew code for piracy as we are about making homebrew code in the first place. The trust comes from the decision that when homebrew conflicts with preventing piracy, we err on the side of preventing piracy. We don't just release something and claim no responsibility if it's used for ill.

Guest · Posted: Thu Apr 07, 2005 2:10 pm Post subject:

Ichan, my response was a bit strong, for that I apologize. It need not have included any personal elements.

Suffice to say, the concepts of not interfering with copyrights and the industry business models are held important here. And it has served this community well.

Its often fashionable to hold nothing sacred, but people here are not out to make politics, screw businesses, or follow OSS religions. They see a console and want to run code, and do it without undue interference. And hey, they might be a part of that industry some day, so why not be a good boy/girl right now ? Can't hurt.