How We Restored a Forgotten Strip Poker Game

today I would like to tell you about what I think is a pretty cool DOS story. You may already be familiar with Artworx. The Florida-based company developed various card games from 1981 until 2015, including several titles for DOS. For obvious reasons, the company was particularly well known for its Strip Poker series.

Around 1995, Artworx also developed two CD-ROM editions of Strip Poker Professional, Volume I and Volume II. The CD-ROMs were apparently sold through regular retail channels, but purchasing the game only gave players access to a limited selection of opponents. Those who wanted more could call a hotline and purchase additional teams. The customer provided the operator with a serial number and received a corresponding unlock code – a classic telephone-based challenge/response system. Of course, there is nothing particularly unusual about this kind of industry using the best available methods to protect its revenue. This was also the case with Artworx and the two CD-ROM versions of Strip Poker Professional.

A proprietary encryption system was used, which meant that a cracker could not simply patch the game to gain access to the additional content. The content itself was encrypted and was only made accessible after entering the correct unlock code. In addition, the protection mechanism was modified between Volume I and Volume II, creating yet another obstacle.

As far as I am aware, no public unlocker for these encrypted files ever existed. What did exist, however, were numerous reverse engineers from the preservation community, including CTPAX-X, who studied the protection system and published valuable information about it. However, the files were never fully decrypted.

The preservation community eventually attempted to contact Artworx programmer Arthur Welsh and persuade him to provide a key for the poker games. Some members were actually successful in reaching him and exchanged emails with him. However, he explained that he was no longer involved with the company and no longer possessed any files related to the games. He had also since retired.

The result was extremely unsatisfactory: the files were still there – directly on the CD-ROM. Yet without breaking the encryption, nobody could access the content, and it was no longer possible to purchase it.

These encrypted parts of both games were therefore effectively considered lost.

Through a flaw in the encryption, the groundwork of numerous reverse engineers, and the use of modern technology, we finally succeeded in recovering the internal 32-bit keys used by the program to stream the encrypted media content.

For Volume II, these keys are:

TEAM1: 0x68647DC3
TEAM2: 0x0DE45369
TEAM3: 0xEAD77ECE
TEAM4: 0x6D270A21
TEAM5: 0x80E57A2D
TEAM6: 0x91EB784B

With these values in our possession, we were able to build an unlocker that automatically decrypts the encrypted container from the ISO and extracts the decrypted files into a directory. This now makes it possible to use all teams in both Volume I and Volume II of Strip Poker Professional. Building on years of groundwork, we finally achieved the decisive breakthrough

Our thanks go to the community, which never gave up over the years and collected valuable details about the protection mechanism used. It is believed that the technology may have originated from Rainbow Technologies.

As always, we will of course not provide the ISO images. However, our unlocker for both volumes is now available completely free of charge.

We wish you many exciting poker nights and are delighted to have contributed to the preservation of these titles!

– Eric