If I put pictures or into a note pad of my public key / private key on a cell phone that has no service or internet, would that be considered safe?
Lets say also the phone will be password protected 8+ digits and the cell phone was kept turned off in a safe.
other than the actual phone not turning on in 5 years later ? how safe would this be as an alternative? could even have usb + paper wallet + cold cell phone in a safe?
thoughts with the cell phone idea?
Every mobile phone has a second operating system which can be activated even if you switch off your cell phone and that makes it insecure.Lets say also the phone will be password protected 8+ digits and the cell phone was kept turned off in a safe.
other than the actual phone not turning on in 5 years later ? how safe would this be as an alternative? could even have usb + paper wallet + cold cell phone in a safe?
thoughts with the cell phone idea?
Only if you remove the battery is secure but then you cannot read your stored passwords.
http://www.osnews.com/story/27416/The_second_operating_system_hiding_in_every_mobile_phone
I would say a small eBook reader like Kobo mini(50$) is more secure as mobile password keeper or brainwallet generator for Bitcoin, Namecoin or other.
Unfortunately there is no proper software installed on it for this purpose.
However it is a Linux system on it and they are some descriptions how to modify it to be suited for this task.
http://www.mobileread.com/forums/showthread.php?t=222123
The processor speed is also low for a key stretching and the screen is small so you need an adapted hash or key generator.(that would work without changing the OS also with html)
Changing the OS settings you could run keepass also on it.
Going over this aspects relating commodity the security would be much higher then by an eBook reader 1. you don't have an automatic network connection and 2. you have a secure OS.
that would be safest method 