Secure privacy dumbish phone

A secure dumbish phone would be created within login levels, open source where possible, hardened hardware and software.

  • OS
    • open source, probably Linux or BSD based
    • minimal, with unnecessary stuff stripped
    • data and memory encrypted
  • hardware
    • open hardware where possible
    • preferably some level of waterproof, shockproof
    • physical kill switches on risky hardware: cell comms, local comms, camera, mic, usb data?
    • tamper resistant / evident enclosure
    • preferably 4G + 5G capable (prevents obsolescence)
    • camera
    • mic
    • LED flashlight
    • wi-fi / bluetooth
    • bluetooth audio only
    • usb c charging and data port
      • fuse to prevent voltage attack
  • firmware
    • tamper evident chip enclosure, should destroy chip if open attempted
    • read only chip with original firmware verifies updated firmware
    • updated firmware must be signed by manufacturer or will show special menu on boot, show blinking led of different color or some such
    • special menu will have message that firmware doesn't match, options: restore original firmware, boot in risky state, turn off
    • in risky state, will have visible sign like blinking led of different color, icon on screen at all times
    • risky state primarily to allow custom firmware if desired or if company goes under
  • software functionality
    • most comms plus camera
    • phone
    • SMS
    • email over IMAP with PGP support
    • possibly open source encrypted chat
    • possibly simple web browser, no CSS or JS
    • notes?
  • login
    • not logged in is "guest" mode, probably calls out only, for handing to unknown person who wants to make call
    • two logged in levels with separate credentials
    • can configure notifications for each comms type, for email each mailbox
      • not logged in: show only icon, show subject, show full message
      • login level one: show only icon, show subject, show full message
    • can configure access for each comms / data type for what level needed to use
      • send / create only, read only, both
    • login level one may optionally see saved photos and other data, certain settings
    • login level two has full access to everything
    • logs out when phone closed or slept, when accelerometer detects sudden movement, possibly other signals of nefarious activity
    • may use password, biometric, or key for login one
    • must use 2FA or long password for level two
    • if dual sim, likely has separate account / login pair for each sim, or second sim can be set for guest mode with full access
  • data retention
    • option to not retain any data of each comms type, camera after initial observation or period of time
    • option to copy each type of data to remote server over SSH / SCP with key, possibly other open protocols
    • option to only store data in memory, gets wiped on reboot or detected nefarious activity
    • can sync to usb flash drive only from level two