Great work!
I confirm the encrypted blinker works on my SD890IS (IXUS 970), and the AF LED must be at the same address, because it turns on immediately and is blinking. I will build the receiver circuit soon and attempt a dump.
If you have time to very briefly describe what encryption was required, that would be great. As jeff666 says, it would be great to try encrypting the udumper program in the same fashion, to see if we can avoid having to set up the full blinker toolchain.