June 15, 2024

Slysoft Commercializes Next-Gen DVD Circumvention

We’ve been following, off and on, the steady meltdown of AACS, the encryption scheme used in HD-DVD and Blu-ray, the next-generation DVD systems. By this point, Hollywood has released four generations of AACS-encoded discs, each encrypted with different secret keys; and the popular circumvention tools can still decrypt them all. The industry is stuck on a treadmill: they change keys every ninety days, and attackers promptly reverse-engineer the new keys and carry on decrypting discs.

One thing that has changed is the nature of the attackers. In the early days, the most effective reverse engineers were individuals, communicating by email and pseudonymous form posts. Their efforts resulted in rough but workable circumvention tools. In recent months, though, circumvention has gone commercial, with Slysoft, an Antigua-based maker of DVD-reader software, taking the lead and offering more polished tools for reading and ripping AACS discs.

You might wonder how a company that makes software for playing DVDs got into the circumvention business. The answer has to do with AACS’s pickiness about which equipment it will work with. My lab, for example, has an HD-DVD drive and some discs, which we have used for research purposes. But as far as I know, none of the computer monitors we own are AACS-approved, so we have no way to watch our lawfully purchased HD-DVDs on our lawfully purchased equipment. Many customers face similar problems.

If you’re selling HD-DVD player software, you can tell those customers that your product is incompatible with their equipment. Or you can solve their problem and make their legitimately purchased discs play on their legitimately purchased equipment. Of course, this will make you persona non grata in Hollywood, so you had better hire a few reverse engineers and get to work on some unauthorized decryption software – which seems to be what Slysoft did.

Now Slysoft faces the same reverse engineering challenges that Hollywood did. If Slysoft’s products contain the secrets to AACS decryption, then independent analysts can extract those secrets and clone Slysoft’s AACS decryption capability. Will those who live by reverse engineering die by reverse engineering?


  1. Try outputting only to the TV and see what happens. When you try and output to two monitors it will only show on one monitor. So you can’t watch it on your laptop and on your TV at the same time.

  2. I dont think DRM is worth it. I fsomebody really wants it they are going to get it. On the other hand, I never knew Slysoft were as big as they are until i read this..

  3. slysoft went off line tonight.whatzzaaup?

  4. Sgt.Jackhacker says


    Is your Inspiron 6000 equipped with Microsoft Windows Vista?
    If the answer there is yes, then you’ve found your problem.

    I refer you here:

  5. Dwight, I don’t think it’s an AACS-related problem in your case. Try a different monitor (CRT or TFT, whatever), plug it into your analog D sub connection and find out what refresh rate and resolution is used when your notebook plays AVI format. Maybe the values are incompatible with your TV monitor.

    And try a different playersoftware as well, for example VLC media player.
    Not the best media player software available, but this one doesn’t use DirectX. Almost all other media players do, so they all might have the same problem.

    My personal recommendation is: CCCP

    (browser-embedded youtube videos don’t use DirecX, they are decoded by the flash plugin, maybe that’s why they work on your monitor. Technically they aren’t different from normal webpages, seen from the grapics cards perspective.)

  6. Dan,

    I hit the F8 key which switches the output from LCD to CRT and it doesn’t solve my problem. Remember, I can see my desktop, browse the web, or view YouTube videos on my 40 inch hidef LCD panel, but when I attempt to play ordinary home video, let alone, a movie trailer from my laptop I stil get that error message – “Unsupported Signal check your device output”.

  7. Dwight,

    Try outputting only to the TV and see what happens. When you try and output to two monitors it will only show on one monitor. So you can’t watch it on your laptop and on your TV at the same time.

  8. I just received a new Sony 40 inch HiDef TV monitor (model KDL-40SL130) from Costco. When I hook that monitor to my Dell laptop (Inspiron 6000) via the RGB 15 pin D sub analog connection I can see my computer desktop on the 40 inch monitor and use the web browser and see web sites and watch youtube videos (flash video format) although the input resolution is limited by Sony to no more than 1360×768 even though
    by TV monitor has full 1920×1080 HiDef resolution.

    However, when I attempt to play home movies (AVI format) or download any movie trailer from Apple on my laptop and watch them on the large screen 40 inch monitor via that 15 pin connection the TV screen goes black and I get the following error message “Unsupported Signal check your device output”!

    So my question to Dr. Felten and everyone who reads this blog is simple.
    Has Sony somehow mechanically limited every laptop from playing movies on their large screen consumer monitors or is this a limitation of my analog laptop as I do not have a digital HDMI connection out (e.g. Apple latops) to plug into the HDMI in on my large screen? Or is this limitation a software issue related to AACS?

    Any input from anyone would certainly be greatly appreciated.

  9. AACS-approved means the money is going into the right people’s pockets.

  10. I always thought that Slysoft is actually funded by ‘Hollywood’. (Part of) the movie industry knows that DRM (CSS/AACS/etc) is bad and harms sales*. By creating (and selling) the best product to watch these movies anyway, they makes sure they are still in control of the movie playback. To preserve their face, this money trail is well hidden.

    BTW, Slysoft was one of the first players to play AACS disks — before the people on the doom9 forums etc. cracked it — if I recall correctly. This strengthens the idea that (someone from) the movie industry might be involved.

    * at least I would never buy a drm’ed song/movie without being able to decrypt it. This way they give me this opportunity and I will buy them.

  11. > Word is that in their latest versions Slysoft is requiring the software to phone home once per disc for newer discs to retrieve critical information

    More precisely, Slysoft has implemented a decryption oracle.

  12. Interesting location for a DRM-circumventing venture, considering the Antigua-US Internet gambling beef. If the MPAA tries to take action againt this software, will the authorities in Antigua respond with “You comply with the WTO ruling against you, first?”

  13. Word is that in their latest versions Slysoft is requiring the software to phone home once per disc for newer discs to retrieve critical information: No reverse engineering possible there.

  14. Michael Donnelly says

    Slysoft’s business value is a lot more than simply the reversing. In order for a company to capitalize on stealing their secrets, the company also has to:

    – Build a solid product around the core sneaky bits.
    – Market their product competitively.
    – Survive the DMCA hostilities (read: be outside of WIPO, like Slysoft).
    – Respond quickly to the changes from Hollywood, which would be impossible if they have to wait for Slysoft’s move to steal it every time.

    Identifying a core piece of the business as the entire business is a bit of a fallacy. They are still susceptible to individuals reversing the software and publishing their findings, but that challenge is hardly unique to the business of decrypting HD content.

    What’s more intriguing to me is how many more companies will go into this model. If you have a lot of demand for a product that consumers feel is fair, but your local laws prevent you from selling it – why not move away from those laws? The Internet makes the world a small place, particularly in software sales. It’s the biggest risk faced by any company (or cartel) that relies on the government to strengthen a business model that is not actually healthy in an open market.