as I read here The problem with the Google Authenticator
The OTP algorithms HOTP and TOTP are based on a symmetric secret key which is also called seed. Using the algorithm, the seed and a moving factor the OTP value is calculated. This means that the seed needs to be protected. … The QRCode contains the seed in clear text. The value O6LVCAVTS2IJ25NKXKOOGCNTJIOFNUXA is the secret key in the so called “base32” notation. This might look complicated to an untrained, human being eye. But the computer takes this as clear text for real. As this is a timebased OTP token (TOTP), each device that scans this code will create the same OTP value. The value will change, but it will be the same value. On each device.
So in TOTP algorithm we have a fixed-single SEED and multiple-changing OTP values.
I rephrase the question: does Nitrokey store the SEED value encrypted in order to be protected against physical attack?