wvmarle:
Not very feasible on a Nano - not so long ago I looked into this, and it was mentioned that the encryption code takes almost 30 kB of Flash, leaving almost nothing left for your sketch.
If I use the flash for encryption and the eeprom for my code? The code is just a reading from Analog and sends the data on serial, nothing too complicated.Which library do you suggest for encryption/decryption?