OK, so here's what I've discovered.
You do need to set up a screen lock (either pin or password), in order to activate encryption - that much we've known already. Here's where it gets interesting (or should I say slippery?).
You can encrypt in one of three ways;
- Device (where the encryption key is automatically generated by the phone - and I'm assuming uses the MEID/IMEI, especially based upon the warning which follows) This is the default choice. If you encrypt this way, you can only decrypt with the same device, and "storage data cannot be decrypted outside the device". HMMM... So that implies that data CAN be decrypted outside the device with another method or tool. Let's move on.
- Password (where the same password or pin you used to set up the screen lock is used to generate the encryption key). This method must be selected manually and...are you ready...is described as "storage data cannot be decrypted without your password", but it says NOTHING about needing to do so in the device. This further implies that there can be a decryption tool/algorithm/application - perhaps running on a PC for instance, that can decrypt that data as long as you have "your password". Makes sense, right? I mean, encryption is only a mathematical formula with a "seed" or "key". If you have the formula, and you have the key, it need not run on any specific device.
- Device+Password (a blend of the two above). This also says "can not be decrypted outside the device AND without your password". So option 3 is similar to option one with an added layer of security. A key and a lock box, versus just a key.
Now, ALL THREE methods also lead you to believe that the data can be "decrypted" if you have the necessary parts. In the cases of 1 and 3, you need the phone (and I take it to mean the EXACT PHONE, IMEI/MEID, everything), and additionally in the case of 3, you also need the password. In the case of number 2, you either need the phone, and for that matter, ANY phone that has that type of encryption, along with the password, OR any OTHER device that has the same encryption algorithm and the password, and you should be able to decrypt.
To the OP - Sam (BeyondReprieve), do you remember which of the three options you chose, or did you simply accept the default choice? If so, it shouldn't ask for a password if the card is inserted into the same phone, and if it does, DON'T TYPE ONE IN! Just hit OK or the Enter key.
If you did select option 2 above, then the password is where we're lacking, and if you chose option 3, well I think we both know what that means. Without both the right phone and the right password, we're done.
Did you ever get the original phone to boot successfully since the last attempts? I SURE hope so! We may be only one button-press away from you unlocking those files. I pray that is the case.
Please let us know.
I didn't get to do the trials yet. Life and work had stepped in the way. I am not here to draw sympathy so I won't elaborate. I do however want to get to the bottom of this once and for all. This appears to be a ticking time-bomb for many and they probably don't even know it. Unless we can successfully reproduce full decryption repeatedly AFTER Factory resets, there are lots of people out there who will potentially suffer similar losses to what you may have suffered. If there's any way I can help to prevent that, I will.
I've decided that doing the tests in ICS Leak is flawed science, since it's a different ROM than you were running, so I'll have to Fastboot back and give it a whirl on the Gingerbread ROMs. This will take some time. If you and others can wait, great. If not, my apologies.
Good luck! :biggrin: