modifying jar files and resigning them?

[spotter]

so If I have a JAR file in a bluray and I modify it (i.e. replace one of its class files with a modified one). I'd expect it to fail due to how the jar files is signed and this class now failing that test.

My question is, is it possible for me to sign things and make them work?

i.e. I have hdcookbook and i can follow these directions

https://github.com/oliverlietz/bd-j/...rity/README.md

and I can generate a root and app cert and sign the jar, and while this worked to get it to play in VLC on my local machine (where I did the signing, so perhaps the local java accepted the key, but othes wouldnt?), it didn't help to play it on other physical bluray players that I had.

any thoughts on what I should do? do certain settings matter? anything I should be on the look out for?

thanks

[DenisRodman]

If you are modifying a jar that you yourself did not create i.e. If you use an original Blu-ray disc, then I recommend using older versions of AnyDVD HD for re-signing. For example, AnyDVD version 6.7.7.0 or 6.7.9.0 or 6.7.3.0. Programs look yourself.

How to use:
1. Edit your class file.
2. Add it to the Jar and replace the original file class.
3. Create an ISO Blu-ray image.
4. Set the settings in AnyDVD HD. Settings - Video Blu-ray - set flags Enable Blu-ray Support, Disable BD-Live, Remove Blu-ray Region Code and select a region that is set your Blu-ray. If the Blu-ray does not have a region, then install any such as A.
5. Mount the ISO image in a virtual drive.
6. AnyDVD itself will see a new Blu-ray and begin scanning.
7. To make sure that the re-signing has passed for this, see the Settings - Status, select your drive and see the message should be the next line "Blu-ray Java signatures fixed!"
8. Copy the Blu-ray to your HDD. Rip Video Disc to Harddisk...

[spotter]

that's using anydvd to do the job (which i guess could conceptually solve the problem), I'm trying to learn how to do it on my own and not rely on it. For instance, a total linux workflow.

[Emulgator]

Thanks DenisRodman !

[spotter]

realized that the above also won't help for UHD, I believe those old version of anydvd will not know what to do with them as standards have changed.

[81ig2]

Hey guys, I'de been looking for a tool to re-sign jar files besides anydvd hd < 6.8 and after signing an entire bluray using the hdcookbook tools and not having it work on my hardware player I was getting frustrated.
I'm not sure why it didn't work as I was replacing all the certificate files app.discroot.crt bu.discroot.crt and id.bdmv.
All I can think is I was messing something up somewhere along the way but I didn't have a software based player that enforced certificates so the process of testing each change was too tedius to continue.
I reached out to the author of xreveal and he was able to put together an adhoc tool that you can use to sign jar files of discs ripped using xreveal or anydvdhd.
I am not 100% certain, but it might work on rips from other tools.
I just don't know if it is merely using the app.discroot.crt certificate to do the signing, or if it relies on the same root ca (which is perhaps embedded in the anydvd/xreveal programs?).

The requirement is that you have a JAR file with a META-INF folder that contains MANIFEST.MF SIG-BD00.SF and SIG-BD00.RSA.
It appears that the tool updates all files, and perhaps uses the existing fields in the SIG-BD00.RSA along with those from the app.discroot.crt.
The generated JAR files worked perfectly on my hardware player.

He has uploaded the tool to https://xreveal.com/download/signbdj.exe
And the invocation is the following.
"signbdj.exe app.discroot.crt 44444.jar"
If you are looking for this feature I suggest you also check out xreveal and also offer support for the author of this great free tool!

One other note on modifying jar class files.
I found that using RECAF 4 was very good.
Recompiled files don't work as they target JAVA version 8.0 language specification.
For whatever reason my hardware player could only recognize java version 3.0.
As such you need to make changes using JAVA assembly then save the file and export.
This preserves the JAVA version 3.0.
RECAF has a bunch of tools to translate JAVA into JAVA ASM which you can then copy into the assembly listing so it makes it pretty easy.

[Logrus86]

Originally Posted by 81ig2

...
He has uploaded the tool to https://xreveal.com/download/signbdj.exe
...

Thank you for sharing this 81ig2!

It doesn't work for me though. I've already checked 3 disks, none of them work after jar modification and signing. Player is Panasonic UB900, discs are UHD.

Could you tell please what player you use and what kind of disc - UHD or regular BD?

[AVX]

I will sign all the jars you want.
Just shoot a PM.