I marvel at how foreign buyers of something as complex as stealth aircraft can have any confidence that the system is not riddled with back doors, remote control capability, "phoning home", surveillance, and kill switches. How would you prove to a foreign buyer that your F-35 would not:
- upload all your secret flight data to a tire pressure monitor every time a maintenance worker checks the tires with the special gauge he has to use, which then retransmits the data when the gauge is put back in the hanger, without needing any cooperation from the maintenance worker
- cause all your F-35s to fall out of sky everywhere in the world when the GPS satellites transmit an extra 64-bit coded message that cause fuel actuators to shut off
- put your F-35 under remote control when a coded microwave message is transmitted directly to the plane during combat or a close encounter
Even children's toys and home appliances are routinely discovered to be phoning home and doing sneaky unexpected things. I'm going to hazard a guess that all large weapons systems are compromised —— perhaps by more than one nation simultaneously since parts and expertise come from hundreds of contractors and many different countries. I'm not aware of any revelations of weapon-system backdoors yet, but we might hear about some of them in the aftermath of the next major war.