Default [Q] Factory default & external encrypted sd card

Hello,
I have a Samsung galaxy s2 with 4.1.2.
The external SD card (and only that) was encrypted.

I did a factory default and now it mounts the external sd card but it doesn't ask for the password. I can see the name of the files but not access them.

How can I access my data ? I know the password, it's the same phone. The automotically backup to google account was on, but I don't know it it backup up the key or something.

Anyway, I am a big fan of Linux (I am using ONLY Linux for more de 10 years) and Android, but if I lost my data from the external sd card this Android OS is a mess, it's even a big danger for a the user.

Why:
- this is not encryption. The external card should be unencryptable even after the os reinstall, factory defaults etc if the pin password is known and the same hardware is used (this should not benecessarily).

So tell me please that I can access my data !


Thank you