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Lynx Encryption?


103 replies to this topic

#101 Shawn Jefferson OFFLINE  

Shawn Jefferson

    Stargunner

  • 1,538 posts
  • Location:Victoria, Canada

Posted Tue Nov 3, 2009 12:04 AM

Quote

I still do not understand what happens after the blocks have been decrypted and placed in memory. There is probably some jsr calls from the rom. Or perhaps a jmp to some address in ram. If Harrys code call stuff in rom then it may have something more in it than just the math.

There is a simple jmp $200 in the ROM after decryption.

In the loader, from what I saw (and I think the loader I grabbed out of the enctest.c program was truncated-ah, yes it was since it contained the blank section between $296 and $2FF), there are two calls to the ROM, a call to $FE00 to setup the cart block to read, and another to $FE4A which I don't know what this does... it appears to be within the main lynx ROM code and may be within the decryption code itself (i don't understand this code and I didn't try to work it out.)

Attached Thumbnails

  • lynxrom.jpg
  • lynxloader.jpg

Edited by Shawn Jefferson, Tue Nov 3, 2009 12:18 AM.


#102 Wookie OFFLINE  

Wookie

    Chopper Commander

  • 167 posts
  • Location:Seattle, WA

Posted Tue Nov 3, 2009 8:34 AM

View PostShawn Jefferson, on Tue Nov 3, 2009 12:04 AM, said:

...(and I think the loader I grabbed out of the enctest.c program was truncated-ah, yes it was since it contained the blank section between $296 and $2FF)...

I explained earlier in the thread that the HarrysPlaintextLoader definition in the enctest.c file is trucated. I discovered that when I figured out the block count framing bytes in the decryption process. I also then posted the full plaintext decryption of Harry's Loader. Make sure you are using that one.

--Wookie

Edited by Wookie, Tue Nov 3, 2009 8:34 AM.


#103 EricDeLee OFFLINE  

EricDeLee

    Quadrunner

  • 5,749 posts
  • Location:Michigan

Posted Tue Dec 1, 2009 6:04 AM

Not sure what this all means... but I am wondering if this will help me figure out what my headerless roms are from the protos I have.
Karri... were you able to get anywhere with that?

#104 Wookie OFFLINE  

Wookie

    Chopper Commander

  • 167 posts
  • Location:Seattle, WA

Posted Tue Mar 16, 2010 9:13 AM

I just received my LynxMan flash cart. My first priority is to finally test my encryption tool and to integrate it into the cc65 toolchain.

--Wookie




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