A1 Grand Prix (Konami)

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By iamweasel2

Hero (577)

iamweasel2의 아바타

22-06-2020, 21:51

NYYRIKKI wrote:

AFAIK network is not required to to play (at least Midnight rally), but this is not the biggest problem here... I tried already years back to explain that I know how the encryption algorithm works and that I am able to completely decrypt the data blocks manually and by that way remove the hardware lock completely, so that it just looks that it has been released as free software. I also offered to remove all the possible user credential related identifications, but at least that was not yet enough...

You spoke with the owner of the game we are talking here before? What did he say?

By sdsnatcher73

Paragon (1094)

sdsnatcher73의 아바타

22-06-2020, 22:01

Ah I see now. Thanks for the explanation NYRIKKI, I did not know there was DRM and fingerprinting on MSX! So I understand there was some hesitation here by the legal purchaser. I highly doubt any consequences would follow nowadays.

It seems unlikely these are the only surviving copies of these games. Although finding another user might prove difficult (and has probably been undertaken before in Japanese MSX community).

By Randam

Paladin (994)

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22-06-2020, 22:04

And I am guessing it can't be bought digitally.

By NYYRIKKI

Enlighted (5590)

NYYRIKKI의 아바타

23-06-2020, 02:12

Quote:

Ah I see now. Thanks for the explanation NYRIKKI, I did not know there was DRM and fingerprinting on MSX! So I understand there was some hesitation here by the legal purchaser.

Yes, indeed Links cartridges included support routines to encrypt & decrypt programs... Header of the file told if the data was public or commercial/personal. In later case the data was ciphered before storing to disk and deciphered when reading. The cipher key was burned in to ROM on factory, so the downloaded non-public files became useless if the disk was separated from original LINKS-cartridge.

The nasty thing is that validity of the key is not checked... The program is deciphered with the existing key and then started... If the key is wrong the computer will just crash in a random way... The system is anyway not fool proof...

British managed to decipher Enigma codes because Germans sent out messages like "nothing to report" that were easy to guess and therefore revealed the encryption key... Same technique works here... Since the public and personal messages use identical routines, it is very easy to reverse engineer the key from ie. personal mails by comparing the data to game manuals, price lists or such. Once you find the common routine you can always reverse the key.

If the hardware key is missing for individual game file the problem becomes more hard as game files don't usually have any bytes in certain place or order... For this purpose I've made a program that uses AI to identify when the deciphered code looks like valid Z80 code... This approach takes a minute or so from the MSX, but so far it has found the correct key without problem from all encrypted files that I've tried. I also made GETID and SETID programs that you can load from the LINKS GUI. They can be used to read the key from the cartridge and to inject a fake key entered by user... This will allow reading disks created with another LINKS-cartridge, but since individual files can include multiple blocks with user defined sizes the complete key removal once and for all means that all blocks need to be deciphered one by one according to load routines on each block.

The Username/Password system was more related to online services, buying games and hiscore lists. LINKS ROM offered games standard interface to ie. upload hiscores online.

iamweasel2 wrote:

You spoke with the owner of the game we are talking here before? What did he say?

It was mostly talk about cultural differences what comes to obeying copyrights. We also had quite a big language barrier between us, but I got impression that he had some role on the past in this LINKS network operational part and that the A1 grand prix was actually multipart game where each level was downloaded separately from the LINKS server.

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