Unravelling Konami's Arcade DRM
1–10 of 28 posts
Re: Unravelling Konami's Arcade DRM
#2I love reading stuff like this.. thanks for sharing!
Re: Unravelling Konami's Arcade DRM
#3After 15 minutes spent trying to decipher this, I simply translated the code into Python and iterated infinitely. Turns out, this is how you perform big-endian addition without actually converting the number to little-endian. An odd way of doing it, but perhaps a compiler optimisation. It turns out they’re actually using AES_CTR, but instead of incrementing the entire counter IV, they’re only using the last 4 bytes. A little strange, but if your encrypted file is 232 16 bytes long, you have other problems to worry about.*
Not all that strange. The "counter block" is normally split into a nonce, which allows you to reuse the same key on multiple messages without generating a duplicate keystream, and a counter; an AES block is 16 bytes wide, so a 64 bit counter is more typical, but I've seen 32.
Doing that can even make sense, if you have bounded message sizes (<64 gigs) --- the larger the space you allocate for the nonce, the safer it is to generate nonces randomly, rather than using a system to remember all previous nonces to avoid collisions.
Re: Unravelling Konami's Arcade DRM
#4MAME has long lacked support for certain Konami games. Is it because of this? Could MAME now support those Konami games, in jurisdictions with no anti-circumvention laws?
Re: Unravelling Konami's Arcade DRM
#5MAME has long lacked support for certain Konami games. Is it because of this? Could MAME now support those Konami games, in jurisdictions with no anti-circumvention laws?
This shows the Konami game running natively on windows.
Mame is an emulator, correct? It seems out of scope.
Re: Unravelling Konami's Arcade DRM
#6MAME has long lacked support for certain Konami games. Is it because of this? Could MAME now support those Konami games, in jurisdictions with no anti-circumvention laws?
Konami didn't start using Windows for its games until IIDX 9th style, Pop'n 15, DDR X, and Drummania V...6 i think?. Before that, it was all custom hardware, based off of the PS1, PS2, or just an in-house creation. Older IIDX for instance uses a combination of a CD drive, a DVD drive, and an IDE drive for storing all its data, not to mention ROMs soldered onto the boards. The MAME team has actually just started to get the older games working, but require dumps which are hard to come by - thankfully the fans of these games have been collecting dumps for years and they are slowly being cataloged and added in.
DDR has been a thorn particularly because they used a custom chip for decoding encrypted MP3 streams in the System 573, something that MAME hasn't wanted to touch due to patents.
I highly doubt the newer games will go into MAME anytime soon - partly because they all run Windows XP embedded, and also because they are most likely considered "too new" for inclusion.
Re: Unravelling Konami's Arcade DRM
#7This stuff has been documented in private circles for over a decade now, and hasn't been made public because these games aren't available to play outside of owning a cabinet in Japan or acquiring the data via less-legit methods. While it's a fun exercise to explore, the real-world application is sadly limited to grey-market implementations that Konami frowns upon, which reinforces why the exposure has been limited.
Re: Unravelling Konami's Arcade DRM
#8This stuff has been documented in private circles for over a decade now, and hasn't been made public because these games aren't available to play outside of owning a cabinet in Japan or acquiring the data via less-legit methods. While it's a fun exercise to explore, the real-world application is sadly limited to grey-market implementations that Konami frowns upon, which reinforces why the exposure has been limited.
Information wants to be free.
Re: Unravelling Konami's Arcade DRM
#9This stuff has been documented in private circles for over a decade now, and hasn't been made public because these games aren't available to play outside of owning a cabinet in Japan or acquiring the data via less-legit methods. While it's a fun exercise to explore, the real-world application is sadly limited to grey-market implementations that Konami frowns upon, which reinforces why the exposure has been limited.
If you're in said private circles, you might recognize the author.
Re: Unravelling Konami's Arcade DRM
#10This stuff has been documented in private circles for over a decade now, and hasn't been made public because these games aren't available to play outside of owning a cabinet in Japan or acquiring the data via less-legit methods. While it's a fun exercise to explore, the real-world application is sadly limited to grey-market implementations that Konami frowns upon, which reinforces why the exposure has been limited.
Information wants to be free.
Not sure how releasing this information benefits anyone. The games are sold and distributed by Konami directly, and only to licensed arcades.