And because of this, systems often fall back to cleartext (esp for ILS which would need backwards compatibility). This allows for jamming sufficient to cause cr

And because of this, systems often fall back to cleartext (esp for ILS which would need backwards compatibility). This allows for jamming sufficient to cause crypto decoding error, forcing failover to cleartext. Spread spectrum (e.g. frequency hopping) can mitigate this by improving jam margin, but still requires key material. The best response is probably jamming (seduction) detection, through good data fusion algorithms. Hard to do directive jamming without sidelobe leakage that could be detected on the ground. Transmitting a signed (AEAD) bitstream should be possible by publishing a public key in the NOTAM. The cost decrease in DRFMs (SDRs) also means that deploying radio receivers with upgradable waveforms is also much cheaper.