Wednesday, January 18, 2006

XCopy9 DVD Copy Software Review

This week I will continue the series on DVD copying programs with reviews on Bling Software's three DVD copying programs, namely XCopyDVD, XCopyPSP, and XCopyPOD. These programs represent the next generation of copying programs and can be purchased and downloaded online individually or in a bundle called XCopy9.

DVD to DVD Copying With XCopyDVD
XCopyDVD is very similar to 123CopyDVD program reviewed last week in that with it you can make copies of DVD movies to writable DVD discs. Its burning engine supports dual-layer burners thus giving perfect digital copies. As well it can also re-compress the movie to allow for older DVD burners and discs which have smaller space available than commercial movie discs. The re-compression process is fast and isn't very noticeable on the copied disk. As well the program allows for all multi-channel audio (including DTS, 5.1, 6.1, etc.) to be duplicated exactly. Finally, the program comes with free online updates and 24-hour technical support. XCopyDVD can be purchased online for just $29.99.

DVD to PSP Copying With XCopyPSP
XCopyPSP is where Bling Software's offerings get interesting. This unique product allows you to rip a DVD movie and re-compress it to fit onto a Playstation Portable (PSP) memory stick. This product is a terrific idea for those with long commutes or to take a movie with you when traveling. The copies made are great in quality, both in terms of sound and video. Plus the XCopyPSP software is rather inexpensive at just $19.99 when purchased online from Bling Software's site.

DVD to iPod Copying With XCopyPOD
XCopyPOD is very similar to XCopyPSP in that it allows you to rip any commercial DVD movie and play it back on the latest generation of Apple iPods. Plus, since the iPod can store up to 150 hours of movies on it you can have around 90 full length movies on it (or the entire series of Seinfeld, etc.). The only drawback to XCopyPOD comes from the fact that the iPod's screen is only 2.5 inches in size and thus you aren't going to see a lot of detail on it. Still the video and sound quality are more than good enough to be able to watch for hours. Note the software is not avilable for Apple computers at this time. XCopyPOD can be bought online for just $19.99.

Have you had any good or bad experiences with XCopyDVD, XCopyPSP or XCopyPOD software? Would you like to see a review of another DVD copying product? Then leave a comment below.

Friday, January 13, 2006

123 DVD Copy Software Review

Over the next few weeks I will be exploring various different DVD copying programs, starting with X-OOM's 123 DVD Copy application. 123 DVD Copy, available for sale online, is a steal at just $29.99. In addition to being able to make great quality DVD to DVR-R/RW copies, it also offers the ability to copy a DVD movie to and from your hard disk. So you can download movies and burn them, or copy a few movies to your laptop's hard drive when you go on vacation. Most importantly there's a free addon to download that enables the copying of encrypted, "copy protected" disks with 123 Copy DVD.

Starting Using 123 DVD Copy
You can download the 123 DVD Copy software quickly after buying it online. It's around 5MB so it took me about a minute to get. After installing and running it you are presented with three options: copy the DVD movie to hard disk (yellow button), copy DVD movie to writable DVD (red button), and burn DVD movie from a file on your hard disk (green button). The most important feature is copying a DVD movie to a blank DVD disk so we'll explore that in detail. The other two features do make nice bonuses.

Copying a DVD With 123 DVD Copy
Copying a DVD movie with 123 DVD Copy is very simple. You put in any DVD movie disk into your computer's DVD drive, select it as the source movie and chose whether you want to copy the feature film only or copy all the menus and bonus material as well. Finally, you can also select which languages you want to copy. I recommend you copy just the feature film and the primary language track. That's because blank DVD disks often have less capacity (4.7GB) than commercial ones do (9GB) and 123 DVD Copy will recompress the DVD movie so that it fits on your writable disk. So if you only copy only the feature film and the primary language there will be more space left for the DVD movie and it won't lose much quality from the original. Finally, to copy the DVD movie, just select your burner, give the blank disk a name and click the start button. It should take less than an hour to rip, recompress and burn an entire movie. 123 DVD Copy is really that easy.

123 DVD Copy Features At A Glance
  • The software supports most DVD burners and blank DVD media including DVD+R/RW and DVR-R/RW
  • 123 DVD Copy runs on Windows XP, 2000, or 98 computers with a minimum of 10GB disk space free and 128MB of RAM.
  • The software doesn't put any "watermarks" or tracking numbers into the copied DVD movie unlike some other commercial software
  • It copies the DVD movie's original surround sound track exactly including both DTS and Dolby Digital audio
  • It recompresses big movies to fit on smaller writable DVD disks
  • Free ripper addon enables 123 Copy DVD to copy encrypted movies
  • Sells online for $29.99, much less than other DVD copy programs
Have you also tried 123 DVD Copy to copy DVD movies? If so then please leave a review the software by entering a comment below.

Tuesday, October 25, 2005

DeCSS Celebrates Its Sixth Anniversary

Six years ago today the DeCSS source code was anonymously posted to the livid-dev mailing list. The code detailed the secret content scrambling system (CSS) decryption algorithm that was only previously only available to licensees of the DVD trade group known as the DVDCCA. With the algorithm out in the open, unlicensed DVD players could easily be made. In fact this was the purpose of the original posting of the code as there were no players available for Linux at the time. Worse for the industry though was that unlicensed players did not have to enforce DVD viewing restrictions, such as region-coding and Macrovision copy protection. With DeCSS public they lost their absolute control of the new movie format. As well the DVDCCA argued that DeCSS would aid with piracy of movies, even though DVD writers were not yet widely available nor were broadband connections. Consequently the DVDCCA moved swiftly to rid the Internet of all traces of DeCSS with a barrage of lawsuits.

This action set off a chain of events that would forever change the nature of the Internet. DeCSS and the lawsuits that ensued tested newly created laws for the first time in the digital age. Indeed, one famous legal verdict in January 2000 ruled that hacker magazine 2600 was not allowed to post the DeCSS source code or even have links to it on their web site. The code was ruled to be a circumvention tool prohibited by the The Digital Millennium Copyright Act (DMCA). In a clearly worded verdict issued a year later, a Second Circuit Court ruled that the DeCSS source code was only "partially protected speech", and that such speech can be restricted on the Internet to help curb piracy. More lawsuits were filed and sites hosted copies of the code were shut down as quickly as they popped up.

An unlikely hero emerged from the DeCSS crackdown. Sixteen year old Jon Johansen (eventually just DVD Jon) was accused of copyright infringement, a charge that carries large fines and prison terms of up to two years in his native Norway. Though not the author of DeCSS, he was a member of the team named "Masters of Reverse Engineering" that had wrote the code. As well he hosted the DeCSS source code on his website for all to download. His trial began in late 2002 and he was quickly acquitted of all charges, a verdict that was later upheld in an appeals court the next year. This was the first major defeat for the DVD trade group.

The spread of DeCSS was never successfully contained. In 2004 the DVDCCA all but admitted that they gave up chasing DeCSS and dismissed a lawsuit they had initiated arguing that it violated California's trade secret laws. Today DeCSS can be easily found on hundreds of websites and has been translated into dozens of programming languages. As well the algorithm used by DeCSS has been widely studied and critiqued by cryptography experts. Still, the DVDCCA does continue to sue authors of software programs based out of America that include CSS decryption code like DeCSS. Indeed in August 2004, 321 Studios, the makers of the popular DVD-X-Copy product had to shut down after being hit with an avalance of lawsuits by the DVDCCA.

As we celebrate the sixth anniversary of the posting of the code we should stop and remember what impact the code has had on the Internet. Piracy of films is now rampant, though one can argue that DeCSS has only been marginally responsible for this. Research on decryption and rights protection algorithms has been all but silenced for fear of lawsuits similar to those that targeted individuals involved with DeCSS. DVD Jon's name has reappeared in the news many times, breaking encryption algorithms in iTunes among others. And the community that had rallied around him and other such figures continues to protect freedom of speech and other such ideals on the Internet. Thought CSS is still used on most major DVD movies, its death is only a few years away. Indeed the successor to CSS called AACS has been recently formalized for inclusion on the new Blu-ray and HD-DVD formats. It will be interesting to see how much of history is repeated should that new encryption algorithm be cracked.

Friday, August 26, 2005

The DVD Content Scrambling System Explained (Part 4)

In the conclusion to the "DVD Content Scrambling System Explained" series, we'll put together all the information already presented and show how the DVD movie data can be decrypted after the disk and title keys are decrypted. The unencrypted DVD movie data can then be played with any MPEG video player software or hardware chip.

CSS Disk and Title Key Decryption

Disk key decryption (DA) and title key decryption (DB) are done using the same procedure with a different pseudo-random byte streams caused by the mode inversion previously described (in the second part). As well, both functions use different input keys to perform decryption. In the case of decrypting the disk key, the input is the player key. In the case of decrypting the title key, the input is the disk key.

To perform disk key and title key decryption, 5 bytes from the pseudo-random stream are generated, with the stream being seeded by the input key. The five byte output is then passed through the key mangling stage seen in Figure 5. This stage uses the encrypted key, a 256 byte scrambling lookup table, and exclusive or logic to yield the decrypted output key.

Figure 5. Content Scrambling System Disk and Title Key Decryption

CSS Data Decryption

After the disk and title keys have been found, the movie data can finally be decrypted using the function DC seen in Figure 6. When decrypting data, the pseudo-random byte stream is seeded with the sector key exclusively ORed with the title key. The resulting byte from the pseudo-random byte stream is then exclusively ORed with the input byte after the input has first been scrambled by a lookup table. This 256 byte lookup table is the same one that is used for key decryption. The output is now the unencrypted movie data.

Figure 6. Content Scrambling System Data Decryption

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Tuesday, August 16, 2005

The DVD Content Scrambling System Explained (Part 3)

In this third part of the "DVD Content Scrambling System Explained" series, we'll examine how the pseudo-random byte generator works. This generator is an essential part of the DVD CSS algorithm and must be examined in detail to understand how decryption is possible.

As was perviously observed, the content scrambling system involves three basic decryption functions: DA, DB, and DC. All three functions involve the same major building block seen in Figure 2. This component produces a stream of bytes that appear to be random, but are repeatable with the same initial seed (with the seed corresponding to the five byte key).

Figure 2: Content Scrambling System Pseudo-random Byte Generator

Mode LFSR17 LFSR25 Seed Value
Disk Key (DA)--Player Key
Title Key (DB)-InvertDisk Key
Data (DC)Invert-(Sector Key) XOR (Title Key)
Figure 3: Differences Between CSS Decryption Modes

This seeding key is fed into two linear feedback shift registers (LFSRs) at the beginning of the process for decrypting a key or decrypting an entire sector. In the case of the 17 bit LFSR, two of the seed bytes are put in the lower 16 bits and a '1' is placed in the most significant bit. In the case of the 25 bit LFSR, two seed bytes are placed in the most significant 16 bits. The lower 9 bits are seeded with another key with its upper 5 bits shifted left and a '1' placed into the 4th bit. The 25 bit LFSR is depicted in Figure 4, with the 3 byte seed value seen in the top of the diagram.

After seeding the LFSRs, the bits are shifted right on each clock tick. The new most significant bit shifted in is comprised of a combination of the current contents of the shift register. In the case of the 25 bit LFSR, bits 0, 3, 4, and 14 go through an exclusive or function to produce the value that is fed back to the most significant bit. This value is also shifted into another shift register to produce an output byte. Much like the 25 bit LFSR, the 17 bit one uses the same logic however bits 0 and 14 go through the exclusive or function.

Figure 4: 25-bit Linear Feedback Shift Register Module

After the two LFSR modules have produced two output bytes, their results are optionally inverted, depending on the decryption mode. Then these bytes are summed with an 8-bit adder. A final resulting byte is produced, with its carry out bit being used as the carry in bit for it next sum. Now that a pseudo random byte has been created, it can be used in the key decryption and data decryption algorithms.

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