View Full Version : Sony LRF cryptic filenames


BfloSabres1
01-17-2008, 01:32 PM
Hi all,
Apologies in advance if this has been already posted, I just joined and didn't find anything in the search.

I just got my Sony PRS-505 and love it. I am in the process of converting other book formats to the LRF format. All is well so far, but I noticed that when I used Sony's software to manage my library, it converts the files to a cryptic filename. When I look at the file using the conversion software I can get the proper title. Is there anything out there than can batch convert the cryptic filenames into the correct book name? I wish to export the books I have purchased and back them up on a disk. The names are meaningless to me for data recovery.

Thanks-

gwynevans
01-17-2008, 01:53 PM
Well, the obvious thing to try is libprs500 & see what that does when you use that to save to disk. I'm not sure off-hand if you can do it direct from the reader or you'll need to import from the reader to the library first, though...

kovidgoyal
01-17-2008, 02:23 PM
Wont work for purchased books as they are DRM encumbered.

DaveNB
01-23-2008, 05:58 AM
I was able to mount the Sony Reader as a filesystem using Fuse on OS X after running the Docudesk Browser application. The Sony Reader shows up as /Volumes/Sony Reader and you can navigate the file system and copy files back to your HD, even copy protected ones. I figured out which of the cryptically named files were which by looking at the Info screen on the reader for each purchased book.

I'm pretty sure I cannot simply copy a .lrx file back to the Sony Reader the same way and expect it to work as I suspect the Sony Connect software performs some fancy authentication/key storage steps on the Reader. Unless of course the .lrx files in question were encoded for my particular Reader's decryption key (which I doubt).

I do however wonder if renaming the .lrx files to something more meaningful like: "Author-Title.lrx" would keep them from being installed properly via the Sony Connect software in the future (ie. You need to keep the cryptic file name intact)?

Anyone else play around with this yet?

Dave

igorsk
01-23-2008, 07:05 AM
I'm pretty sure I cannot simply copy a .lrx file back to the Sony Reader the same way and expect it to work as I suspect the Sony Connect software performs some fancy authentication/key storage steps on the Reader. Unless of course the .lrx files in question were encoded for my particular Reader's decryption key (which I doubt).

Yes you can. The files ARE encrypted with a key specific to your account, and decryption key is stored in Reader's keystore when you register it.

I do however wonder if renaming the .lrx files to something more meaningful like: "Author-Title.lrx" would keep them from being installed properly via the Sony Connect software in the future (ie. You need to keep the cryptic file name intact)?
Filename doesn't matter. However, you'll have to reimport renamed files into the eBook Library.

rozie123
01-23-2008, 12:39 PM
Too late I learned that any books purchased directly from the Sony Store and downloaded to the Reader encrypts the name on the computer and the name can only be discerned in the Library or the Reader. I now know that if I purchase the book in .lit form and use the LIBPRS500 to convert I can save it to my computer and give it whatever name I want.

Sometimes the books are cheaper from Sony. Go figure.

NatCh
01-23-2008, 12:54 PM
Why not just rename the LRX file to something usable? (The names aren't encrypted, just cryptic) If you do it as you buy them it's not difficult to figure out which are which, unless, of course, you habitually buy a bunch of books at a time. :nice:

I just copy them to my "storage" area and rename them there. When I'm done reading them I delete them out of the eBook Library software and the funky name is gone, but the version I have stored has a name that means something to me. Neither the eBook Library nor the Reader itself cares what the filename is when it's re-imported they just go by the meta-data. :pleased:

DaveNB
01-26-2008, 02:06 PM
Yes you can. The files ARE encrypted with a key specific to your account, and decryption key is stored in Reader's keystore when you register it.

Interesting.

That is more time/resource intensive for Sony as they have to create a custom file encrypted for each account on the fly/at the time of purchase. But Crypto wise, it's much more secure assuming they're using public key encryption. This way only the Public/Decryption keys are out there in user's hands and there is no way (hopefully if they used a good encryption method) to derive their Private/Encryption keys (specific to each account) that they hold exclusively on Sony's servers.

Less flexible than if their books were encrypted with a global Private Key for all books, with the Public Key embedded in each book that is further encrypted by the individual device's/account's specific key. This way the whole book doesn't have to be re-encrypted over and over for each purchase but only the portion that is the decryption key. But some crafty hacker could intercept the embedded global Public/Decryption Key during it's unscrambling process and subsequently be able to unscramble ALL eBooks...

The first (more secure as their master encryption key never leaves Sony's control and there is no one key that will unlock all eBooks) method requires a sophisticated key management database and more horsepower on their end to do all the whole file encryption on the fly. But then again, eBooks aren't huge files (as opposed to let's say really high bitrate music or video) so given modern computing resources, this added processing overhead is trivial.

This is all in theory anyways as we don't know exactly how it all works.

Filename doesn't matter. However, you'll have to reimport renamed files into the eBook Library.

Cool, thanks that is good to know as I've been renaming my purchased files to something I can recognize more easily for archival purposes.

It's great to know that they are totally self contained and I can use another program (non Sony Library software) to reload them onto the Reader in the future.

Thanks,

Dave

SFReader
01-29-2008, 03:49 PM
Interesting.

That is more time/resource intensive for Sony as they have to create a custom file encrypted for each account on the fly/at the time of purchase. But Crypto wise, it's much more secure assuming they're using public key encryption. This way only the Public/Decryption keys are out there in user's hands and there is no way (hopefully if they used a good encryption method) to derive their Private/Encryption keys (specific to each account) that they hold exclusively on Sony's servers.
[snip]
Private key stored in your account on their server, public key on your reader. Each book encrypted to your private key.

Time/resource intensive? This is Sony. If they start to see a queue of transactions all they have to do is activate another cluster. And e-books are relatively small, so the time to encrypt one would not be a large issue. I wish it took more. Not a DRM fan.

:bookworm:

dsuden
04-18-2008, 06:06 PM
Wont work for purchased books as they are DRM encumbered.

Hi Kovid... I love libprs500 and have sent you a donation! If I am understanding you correctly I've encountered a quandry. If I upload files from Sony E-Book Library, it messes up the uploads done with libprs500, but if I do the uploads using libprs500, I can't send over the books I have purchased from Sony Books. Is that correct?

Dane

JSWolf
04-18-2008, 06:08 PM
LRF is the form of BBeB that has no DRm and LRX is the form of BBeB that has DRM. So when you purchase an eBook from Sony, you get an LRX file.

moz
04-18-2008, 07:16 PM
But Crypto wise, it's much more secure assuming they're using public key encryption. This way only the Public/Decryption keys are out there in user's hands

You're right - that prevents users forging encrypted books from the Sony store. I'm not sure it's a huge problem, but that solution does work. It doesn't affect the piracy problem at all, they're still shipping an encrypted file along with with everything needed to decrypt it to the user.

I'm in the "if I have to buy DRM, I buy .lit because it's easy to crack".

kovidgoyal
04-19-2008, 12:08 AM
You can use the save to disk button of lp500 to save the books directly onto the hard disk, and then add them to the sony library program. If you have a 505 you can use the save to single directory function to save the book files directly onto the reader as well (they wont show up in the list of books on you reder until you unplug it), this will not cause interference.

HarryT
04-22-2008, 02:44 AM
Apologies if I'm missing something obvious, but why don't you just rename the file to something meaningful after you've download it from the Sony Store? The Reader doesn't care what the file is called.

dsuden
04-22-2008, 09:49 AM
You can use the save to disk button of lp500 to save the books directly onto the hard disk, and then add them to the sony library program. If you have a 505 you can use the save to single directory function to save the book files directly onto the reader as well (they wont show up in the list of books on you reder until you unplug it), this will not cause interference.

Thanks Kovid. I need some clarification. If I am using libprs500 to manage my library, and thus, my Sony Reader doesn't contain any DRM books, how do I use librprs500 to save DRM books to the hard disk? I'm sure I'm just misinterpreting what you're saying.

kovidgoyal
04-22-2008, 11:05 AM
lp500 doesn't manage DRM books

dsuden
04-25-2008, 07:43 AM
Kovid, since lp500 doesn't manage DRM books, is it possible for me to use the eBook Library to upload my DRM books to the Sony Reader, and lp500 to upload and manage my non-DRM books?

kovidgoyal
04-25-2008, 12:23 PM
Unfortunately not.