If I store the WiFi Password in the eeprom and someone takes the device, is the password save or readable from others?
If I code the password, e.g. with a PIN, is the compiled code readable?
Thx,
Mike
You can encrypt the password.
Is it possible to read the sketch out of the arduino? Or can I place a secure key in the sketch to secure the eeprom content.
j3sus:
Is it possible to read the sketch out of the arduino? Or can I place a secure key in the sketch to secure the eeprom content.
It is possible to read the flash contents unless you set some lock bits to secure it. But it is machine code, not C source. It would be an extremely difficult job, someone would have to want to break into your wifi network very badly.
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But if you hard code the decryption password into the sketch, it defeats your purpose (I assume) of having it in EEPROM, which is that it can be changed.
Even flash memory can be cracked with special electron microscopy techniques. So your first job should be to decide how important your secret is, so you can decide how difficult you will have to make the job of cracking it.
Note that a wifi password that is not periodically changed is unsafe anyway.
Encrypting the password and placing it in EEPROM will allow you to change it at will and prevent anyone without a full understanding of the flash code, from using it. That's because the key will be stored in flash.
Thx, I had the same idea.
Using a simple byte array to XOR the password and store it in the eeprom. This will allow me to set and read the 'secret' and it will be enough complicated to avoid breaking in. Even from a technically skilled person.
If flash memory is not readable with a simple device from ebay then it will be secure enough.
j3sus:
Using a simple byte array to XOR the password and store it in the eeprom. This will allow me to set and read the 'secret' and it will be enough complicated to avoid breaking in. Even from a technically skilled person.
Muhahaha... 
j3sus:
If flash memory is not readable with a simple device from ebay then it will be secure enough.
You don't need a device to read flash. Just the right software.