"invalid PID checksum" when using mobidedrm, even though it IS valid.

[axx83]

Hi everyone, I have the same problem as many of you but I simply cannot make it to work in any way. I want to read it on my cybook !!!

I bought a book from mobipocket (never ever anymore I'll give you my money you stupid bastards) before putting the name of my device, installing the software or anything.

I use linux, when I downloaded the file from the website Calibre said it had drm. I installed mobiread in my windows paritition and downloaded the file from inside the program, it asked me for login and password and opened the file. I then plugged the Cybook, with the mobipocket firmware, uploaded the file which opens just fine.

I then checked online for dedrm and followed the procedure. I tried using the file directly downloaded from internet, the one on windows after I had opened it, the one on the reader after I had uploaded it from the software and opened it inside the reader. I tried each one of these options with the ebook reader pid, windows pid, even mobiread under linux wine's pid (they all show on mobipocket website).

NO SUCCESS, it always give me Error: invalid PID checksum

I want to read this book on my cybook reader with its epub firmware as I have numerous epub books, I need to dedrm it and convert it.

Please guys help me, drm suck so bad it hurts

[axx83]

UPDATE

Sorry guys, it finally worked, it seems that among the many many options I had to try I was skipping one, I tried again with the cybook's file and the cybook's pid + dedrm 0.13 and it worked :-)

[Sydney's Mom]

Isn't that just the greatest feeling?! Congratulations and enjoy.

[axx83]

IT IS !!! I am definitely never going to buy another book with drm, but if it's absolutely my only choice (as for the book I was referring to) I will probably buy it in mobi format so that I can break it easily.

[JSWolf]

Originally Posted by axx83

IT IS !!! I am definitely never going to buy another book with drm, but if it's absolutely my only choice (as for the book I was referring to) I will probably buy it in mobi format so that I can break it easily.

ePub actually is easier to break the DRM once the key file is generated.

[Sydney's Mom]

Originally Posted by JSWolf

ePub actually is easier to break the DRM once the key file is generated.

I respectfully disagree. You can find a mobi DRM plug-in, so you just have to import the book into Calibre. Actually, takes some of the fun out of it.

[meiniet]

I tried this, with an 8 digit PID (the ten digit version, without the two last digits), but got "invalid checksum" again. It also showed the "right" PID, and that was the 10-digit PID that I used in the first place, so now I am stuck again...
Who can help me?

Originally Posted by red_dragon

You could disable the PID check and examine what mobidedrm expects. After making the changes you have to pass a 8 char PID to the python program:

(Be careful with the indentions)

	def __init__(self, data_file, pid):
### BEGIN NEW CODE ###
		# Calculate PID checksum if just the first 8 chars are specified
		if len(pid) == 8:
			pid = checksumPid(pid)
			print "Full PID is %s" % pid
### END NEW CODE ###
		if checksumPid(pid[0:-2]) != pid:
			raise DrmException("invalid PID checksum")
		pid = pid[0:-2]

Does it work for you?

If the decrypted result is garbage then your PID is not correct.

-Red Dragon

[JSWolf]

Originally Posted by meiniet

I tried this, with an 8 digit PID (the ten digit version, without the two last digits), but got "invalid checksum" again. It also showed the "right" PID, and that was the 10-digit PID that I used in the first place, so now I am stuck again...
Who can help me?

What version MobiDeDRM are you using?

[djpyle]

I'm having the same problem. What I really don't get is that it's only happening with some books. I created a Calibre plugin that works for the majority of my books, but recently, some of them aren't importing with stripped DRM. When I run the scripts in Terminal, I get the "no key found. maybe the PID is incorrect" error. And this happens with every version of MobiDeDRM I have. I think I've tried just about every patch suggestion out there. I don't know what else to do. What would make it work with some books and not others?

[KevinH]

Hi,

One possible explanation is that the source of your books is a standalone Kindle ...

Kindle has recently updated its firmware to 2.5 and this change has changed the way PID's are used from one per device to a unique PID used for each and every book/user combination. Without this unique book/user specific PID, you can not run any of the tools.

So if your Kindle firmware updated recently (wirelessly?), then its single PID can no longer be used.

There are workarounds if you use Kindle4 For PC but for standalone Kindles - unless you are using version 1 which has no firmware update - any recent firmware update will prevent you from using a known PID in the way that you want.

PM me if you want more info.

KevinH

[tt2nn]

These is one guy who tell me that he can buy books from amazon with a very low price. Is it possible? How can he strip the drm?

[IUNO]

Hi,
do you mean that if i'm looking for my kindle 3 Pid, i won't find it through the python string, and that all this tools are useless to me?

Originally Posted by KevinH

Hi,


Kindle has recently updated its firmware to 2.5 and this change has changed the way PID's are used from one per device to a unique PID used for each and every book/user combination. Without this unique book/user specific PID, you can not run any of the tools.

I've been trying to strip the drm from a book i've bought on cyberread, and i always get the "invalid checkum" or the "maybe your pid is incorrect" message.

[KevinH]

Hi,

Yes, I think the Kindle 3 comes with firmware >= 2.5 automatically.
If so you can no longer copy books from your Kindle 3 and use the MobiDeDRM.py script since there is no way with that device to determine the book specific PID. Amazon has improved the security via that firmware update and all newer models have that.

A solution is to get "Kindle For PC", register it, download all of the books you have already purchased for your Kindle 3 onto it (via the "Archive") and run K4PCDeDRM.pyw on them.

Google "Apprentice Alf's Blog" for more info, links to tools_v1.9, etc since none of that can be linked to from here.

KevinH

[KevinH]

Originally Posted by IUNO

Hi,
I've been trying to strip the drm from a book i've bought on cyberread, and i always get the "invalid checkum" or the "maybe your pid is incorrect" message.

If you buy a Mobi book from someplace other than Amazon, you have to provide a PID of some sort so that the vendor can encrypt the file with the PID.

If you can download that book (not via your Kindle 3) and know the PID you provided, you should still be able to process it, I would think.

My previous post was only about books bought from Amazon via your standalone Kindle device (in this case a Kindle 3).

Hope this is clearer,

KevinH

[IUNO]

Thanks for the quick response.

I'll look around anf and let you know if I succed in making that ebook work on my kindle