4 ms·
A set of encryption keys for a critical system is another point of failure: when there is a problem with the keys the system stops working. I'd posit that the
by femto 7y ago
A set of encryption keys for a critical system is another point of failure: when there is a problem with the keys the system stops working. I'd posit that the risk of a failure due to a problem with the keys is greater than the risk of a failure due to spoofing, so the safest solution in practise is to leave the encryption out until failures due to spoofing are more common than failure due to keys (meaning it is unlikely that encryption will ever be installed).
- angry_octet 7y agoAnd 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.
- AnaniasAnanas 7y agoFor something like airplane signals you do not need encryption though - you only need to verify the integrity of the data, which is done either by signatures or MACs.