A89: How TI's keys work
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A89: How TI's keys work
Judging by the 83+ SDK beta, you guys are all waaaaay off.
First of all, the way app signing works is different from what you've
described. The application itself is just modified to tell the calc that it
requires some "certificate(s)" to run. The certificates are what has to be
generated specifically for each serial number, and THESE are heavily
encrypted. And I doubt you'll get anything at all out of that.
Second, TI does NOT just sign any app you send them. Normally, they'll only
do it for those who BUY the SDK - for all other purposes, the free SDK is
just a listing of ROM addresses. The 83+ apps out now - like calcsys - were
signed because TI has given us SDK beta testers the opportunity to get an
app signed for our work -- actually a fair decision on their part.
Also, the serial number on any HW1 calc can be changed. The whole reason
HW2 was released is to fix the security bug allowing ROM modification on old
calcs. FYI, it's the same bug Archive Utility uses, and although no one's
tried yet the address is known (I've seen it somewhere) and it COULD
theoretically be done.
-Scott
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