I've been trying to reverse engineer a paid android app that writes out some binary data so that I can export that data into other programs (it's a run/walk timer app, if anyone's curious, and I'm trying to get its GPS traces out). However, it looks like the apk is encrypted and stored in
There's a nice blog post that says the encryption used is TwoFish, with a key stored in
/data/misc/systemkeys/AppsOnSD.sks, but I haven't been able to decrypt the file using the naïve strategy of just using that key directly with TwoFish on the
How can I decrypt this to get an apk I can actually analyze?
Note: I realize that this information is considered somewhat delicate in places like xda-developers, since it could be used to enable piracy. I have no such intentions, I just want to examine the serialization code.