Storage protection

Content Protection for Prerecorded Media. Similar to CPRM, but designed for prerecorded discs. This system protects dvd-audio. As with CSS, players have a key which is used to decrypt another key stored on the disc. Removing that key will revoke a player. The decrypted key is used to decrypt the content. Managed by the same people as CPRM, and also part of the CPSA. The protection is similar to the CSS system, so manufacturers and content distributers are understandably too nervous to use it currently, instead draging out the CD-audio format as long as possible :-). The specs are available from their website, but when I tried to get them I couldn't get a response, after several attempts and a few weeks of trying. Emailing edventually got a response from an actual human, who emailed me the PDFs and mailed me some example code. I cant find the files anywhere on the web or p2p systems, so its possible there is a bot looking for unauthorised redistribution. Im curious through, so im going to let everyone download them here just to see if they are activly stoping redistribution. I remind people of my legal policy: If I recieve a complaint the offending files will be immediatly removed with a minimum of fuss. But if I recieve a warning letter from the ISP the files will not be removed and most of usenet will be informed. I may not be able to host these files for long if they are being monitored, so everyone download them while you can. And when your done host these on every p2p network.

CPPM was developed by 4C (comprising IBM, Intel, MEI and Toshiba) and uses 56-bit keys, instead of the 40-bit keys used for CSS, and the Cryptomeria Cipher (C2) for content encryption. Sounds more secure than CSS. The designers can learn from their mistakes :-). It should suffer from the vulnerability that broke CSS through. Sooner or later a player will be built or written which doesn't hide its keys well enough.

Like CSS, CPPM requires the drive be authenticated. The authentication system is identical to that used by CSS, so that current drives can play DVD audio (althrough I dont know of any DVD audio software players :-). Althrough that means the authentication system is effectively cracked already, that is not enough to decrypt the audio data itsself.

Also no protection, but do not confuse these with magicgate (see below). Unlike compactflash these cards are propritary through, owned by sony. They can only be used by companys who license it under a restrictive contract and a non-disclosure agreement. There is evidence sony is attempting to abandon ordinary memory stick in favor of its almost identical magicgate format. Magicgate is frequently mislabeled as memory stick, either accidentially or to take advantage of better trademark recognition. They can be identified by color: memory stick=purple, magicgate=white.

Careful when buying memory stick for older equipment. Due to sloppy planning, Sony was forced to abandon backwards compatability when they released the 128M sticks. As a result some old equipment wont take 128M or larger memory stick.

Magicgate is related to memory stick, the same way securedigital is related to multimediacard. Sony originally devloped the memory stick media for portable applications, espicially MP3 players. Unfortunatly SDMI requires DRM technology in the media itsself. Securedigital is a DRMed version of multimedia card to use on MP3 players, and Magicgate is a DRMed version of memory stick to use on MP3 players. Magicgate works in memory stick equipment and vice versa but you need DRMed drive and media to use protected files.

Sony has been doing its best to make magicgate the dominant flash format ("the new floppy"). All sony products use magicgate now, includeing the ps2. Magicgate protection is used to protect ATRAC3 files on the CLIE player, so those cant be played from ordinary memory sticks. Magicgate can be identified by color. Normal memory stick is purple, magicgate is white. Unlike MMC/SD, magicgate cards are no faster than ordinary memory stick.

Magicgate protection is based round and part of the sony OpenMG system

The Sony Playstation2 console memory cards are actually Magicgate cards, but are in a differeny physical package. I dont know why, perhaps they want to stop PCs from messing with game saves where all sorts of fun things could be done, such as editing code to insert a bootloader and run copies without a modchip or editing save games.

Compactflash cards have absolutly NO copy prevention technology. They are just small solid-state hard drives. I include them here only for comparison with the securedigital storage below and as an excuse to tell everyone how great they are :-). However the compactflash website does mention plans to produce CPRM-complient cards, and the CPRM does include specs for compactflash under the obscure title of "Portable ATA storage". This is also the infamous hard drive protection system. Althrough this part of CPRM is, according to 4C, intended only for portable media it is designed so fitting a hard drive with it would be trivial.

Compactflash cards are effectivly solid-state hard drives. They can boot, you can even partition them. They can connect straight to an IDE bus with the right adaptor. These are the fastest removable storage card, but they are not used much in MP3 players (they like securedigital cards instead, see below), so for now they are confined to digital cameras, where they are very popular. They are very fast. You could put linux on this and boot from it if you wanted. Some people have.

I am finally able to explain this properly, now DVD recorders using it are available. Content Protection for Recordable Media is a very versitile technology which can protect audio or video files in various formats. DVD-R and RW, compactflash, CD-R and RW, MMC, SD, just about anything. But the media must support the CPRM technology

Each disc has two codes on it: A 128-bit UI which is fixed and written at the factory - of which 40 bits are unique to the disc and the rest identify manufacturer, media type, perhaps a few other things - and a serial which can be incrimented using a CPRM command. Note it can be incrimented, but not just set to a new value. CPRM-protected files are encrypted using both of those codes (plus a CPRM secret key). They play from the disc they are encrypted on, but wont open if copied to a disc with a different UI. A utility will move a file to a new disc, secure erase the old file, incriment the UI and reencrypt everything on the disc. Basicly, CPRM attempts to apply the same restrictions on data as on a normal physical object. You can move it round, give it away or sell it, but you cannot copy it.

Officially this is not supposed to be used on hard drives, but its technicly possible. The 4C entity which owns the technology has requested a command byte for it should be added to the ATA spec, they claim its to support removable cdrom, compactflash or zip which connect to an ATA bus. This isn't fooling anyone, because everyone knows the ATA spec only coveres fixed drives. Removable media is covered in the ATAPI extension. Through officially CPRM is not to be used on hard drives they are trying to keep their options open. There was an attempt to get it on hard drives but complaints about possible abuses by spyware and privacy problems discouraged it quite well, and if asked the 4C keeps downplaying it, sometimes denying it altogether dispite the small scandal.

You could just make a raw copy of a protected disk, copy the file off using a CPRM-complient copier, and rewrite the raw copy. Of course they thought of that one. When you move a protected file off the UI on the disk is incrimented and all files reencrypted. The standard actually reserves an ATA command byte the , "increment UI" command.

Its actually a lot more complicated than that. I greatly oversimplified. Different versions are used for CD/DVD and everything else, since CD/DVD does not allow incrimenting the code. I do have a few PDFs explaining it in fantastic detail, with everything except the keys. I got those PDFs using much messing round at the 4c entity website, where they needed me to fill in a very detailed form several times before they would post me hard copies of some of it and email the rest. I filed in the form, in detail, with correct information. Several times. I didn't get anything, even after months of waiting. Edventualy I emailed them and somehow managed to get a human response. They emailed me the PDFs and posted me code for the encryption and decryption, minus keys of course. Im supposed to fax a reciept to them now but I dont have a fax machine. Before actually submitting personal details to their form I searched the internet without success. Noone has it. To save others the difficulty of the uncooperative order process, I put them up here. My legal policy is to quietly take down anything I am emailed about, but to make a loud PR-damageing fuss if someone complains to the ISP. Once these are downloaded please share the file on any p2p networks you use.

CPRM is used by all DVD recorders, but no (current) DVD recorders apply CPRM to every recording, only to generational copies. The main effect of this is to destroy backwards compatability. Discs which would otherwise play perfectly on DVD players and PCs are unuseable on those platforms because they do not support the CPRM system. AFAIK there are no CPRM-compatable PC DVD players at time of writing (may 03)

The crypto is some form of the C2 cypher, 56-bit. Same as the CPPM encryption.

There have been several attempts to make CDs or DVD which self-destruct, for use as no-return rental discs or as promosional discs. One method, which was being devloped in '96 by Hide and Seek technologys, uses a photosensitive polymer to make the discs inner layer. The reading laser damages it, and edventually the disc is ruined.(src. New Scientist 2108). This is a unique system in that the disc can be read once and only once (unless left in direct sunlight, presumably). Other self-distructing discs react with air and fail after a set (approximate) time from opening the packaging, through the materials and details vary.

The earliest I know of was a disc which shrink-wrapped in nitrogen, which reacts with oxygen when unpacked, becomeing unplayable after a few days. This is was tried commercially, It was used as a magazine coverdisc once, but wasn't a success.

These technologys are usually unreliable. They have a limited shelf life, and the rate of degredation depends on laser and temperature. Leaveing the disc with the data side up in direct sunlight can damage it. They would also be ineffective. As soon as someone rents the disposabe disc they would just put it in the PC and rip it :-)

The current leader in self-distruct discs is Flexplay, who have devloped a process for produceing DVDs which are useable for only 48 hours after opening the package. The technique appears to involve a reaction between the disc polymer and oxygen. Buena Vista Home Entertainment, one of Disney's main distributors, announced they intend to sell Flexplay discs as non-return rentals in the US starting Auguest 2003. These discs, through they use Flexplay technology, will be labeled "EZ-D". Buena vista is also well known as the company that gets its name stuck to the Disney productions which would otherwise threaten Disneys family-friendly image, such as Scrubs :-). Flexplay claims the discs will remain playable for 48 hours anyway, but given the unpredictable rate of chemical reactions under those conditions I would say it could be anywhere from 30 to 60, depending how well the storage instructions are followed. Flexplay or EZ/D sales have been very low, through they seem to be popular for shoplifters. Presumably they dont have time to read the packaging.

A recent entry is the DVD-D, designed by Swiss company FDD Technologies AG and manufactured by French SNA. This is wrapped in vacume, and lasts until eight hours after opening. This improved accuracy over flexplay is made possible by only using the degrading plastic on the area of disc covering the CSS keyblock. This also prevents the disc expiring half-way through a film, and neatly removes the period of clicking sound and juddery picture that would otherwise be produced on a just-expiring disc.

Once these discs have degraded, they are more-or-less useless. However, if only the CSS key block is unreadable, there are weaknesses in the CSS system which may allow the disc to be decrypted without the keys. See the section on CSS.

Dont be confused by the name, this technology from sony isn't open at all, its actually very propritary. Sonys intrest in propritary hardware and intellectual property abuse is nearly as bad as microsofts. The openMG system is based round the OpenMG jukebox application, with the DRM in the "OpenMG Secure Module" component, and can be found protecting every sony product which uses MagicGate cards, even their expensive Aibo dog, and is also part of the Sony NetMD PC-to-minidisc system. OpenMG is fuctionally similar to the WMDRM system. It allows websites to host protected files which can be downloaded by openMG jukebox, and played. But not copied to other systems and played. These tracks can then be exported to portable players using the familiar check-in check-out system: The file can be copied to a number of players determined by the copyright holder, but once the specified number of copies have been made the file cannot be copied again until one of the original magicgate cards is returned and openmg jukebox allowed to secure-erase the file from the portable card. Althrough all sony portable digital music players (which they still call walkmen, as they have the term trademarked) support the technology, no service is using it for music distribution. Microsofts WMDRM system got in first, and openMG doesn't offer anything WMDRM doesn't

OpenMG stores music in .OMG files. There are no cracks for openMG, but there are rumors someone is working on it, exploring netmd.dll calls and a possible DLL patch. I came across a post about it in a forum. The analog loopback cable, or better still a digital loopback cable, still work. Note that unlike Microsofts equivilent, WMDRM, OpenMG does not have the unfair advantage of low-level access to drivers, so it cant disable digital outputs and loopbacks during playback.

I couldn't find any specific information on netmd.dll other than a vague mention of the function IID_IOmgPmTrackList able to access a variable m_rights. Note that the adware popup-launcher CoolWebSearch will also create a file netmd.dll - camoflage.

OpenMG is a SDMI-compliant protection for portable players. Its the only SDMI implimentation I know of. SDMI has been mostly vaporware because of the near absance of legal DRMed music on the net. If all people want to put on their portables are MP3 files, theres no demand for SDMI capability.

The OpenMG Jukebox software needed for interfaceing to NetMD and Sony portable music players is unpopular. Users describe it as intrusive, restrictive, awkward to use and just ugly. RealONE can be used instead of OpenMG Jukebox with the right plugin, but the OpenMG Secure Module component must still be installed, and realONE is probably even worse.

Someone emailed me with this question:

I came across your website while investigating why I was not able to transfer MP3s from storage on CD to the minidisc itself after checking out the file. OpenMG returns an error when I try to write these files to minidisc (not when I am checking them out though), an error reading "No Copyright Information found" - however, when I put these files in a directory on my hard disk, I can check out the file and write it to minidisc without a problem. Do you know why this is?

I cant explain it, perhaps a bug in the software makes it treat MP3 on CD in the same way as an audio CD, but the problem may help some openMG user get their MP3-on-CD collection transfered, so I put it on the website anyway