'Sector structure protections'
Author:Lord Crass (guest: search)
Date: Tue, May 03rd, 2011 @ 00:33 ( . )

After looking at Infiltrator's protection, I noticed that this one is a "shrink-wrap" style protection that is used on many, many games. It counts the bytes in the data and header blocks and gets the byte before and after the sync marks. It retrieves this info from 16 sectors on a track (which differs according to the title) and builds a table that's used to decrypt the first block or two of the protected file. Frequently the protection is run through twice, sometimes on different tracks. This protection would defeat any software nibbler as it requires the track to be written in one pass.

I don't know who wrote this or what it's called, but there's usually the text "HI MIKE!" in the drive code. Referring to Mike J. Henry, perhaps? Sometimes the text is "LATER!", and once I saw "NEW TWIST" (on Fairlight). Since it's such a common protection, it should probably be given a name and referenced in the database and/or in an article. This is also the one UH1/NiVEK wrote a crack tutorial on for Robocop.

Nearly all of these titles are broken on any version of Vice newer than 1.2. The ones with the protections on the higher tracks (>=18) have a better chance of loading in newer Vice versions due to the way the sync mark is laid out.

I've attached a list of the titles that I've been able to confirm. There's probably many more. Data East, Mindscape, and Br0derbund were heavy users of it.

Attachments:
1304397037_HIMIKE.txt


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--* Sector structure protections
5/03/2011 @ 00:45--Lord Crass
5/04/2011 @ 22:54----Lord Crass
5/05/2011 @ 02:54------Nate
5/04/2011 @ 23:34----J Achernar
5/03/2011 @ 09:51--Pete Rittwage
5/03/2011 @ 19:27----hyper active
5/03/2011 @ 20:51------Lord Crass
5/04/2011 @ 22:15--Lord Crass
5/04/2011 @ 23:05----hyper active
5/04/2011 @ 23:29------Lord Crass
6/27/2011 @ 20:20--Lord Crass

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