Maybe I’m confused about the amount of overhead digital signing / verification adds to communication, but do you think that works at missile speeds? (I don’t doubt that it works at drone speeds.)
[To be clear, I’m trying to imagine the whole “distant spotter + laser transmission to missile” system, where increasing the length of messages increases the amount of time you need to have successfully targeted the missile in order to successfully transmit a message.]
Overhead is negligible because military would use symmetric cryptography. Message authentication code can be N bits for 2^-n chance of forgery. 48-96 bits is likely sweet spot and barely doubles size for even tiny messages.
Elliptic curve crypto is there if for some reason key distribution is a terrible burden. typical ECC signatures are 64 bytes (512 bits) but 48 bytes is easy and 32 bytes possible with pairing based ECC. If signature size is an issue, use asymmetric crypto to negotiate a symmetric key then use symmetric crypto for further messages with tight timing limits.
Laser links are fast. A digitally signed message can be extremely small. Suppose the message is 2048 bits with 128 bytes of payload (my cords, relative target coords, your coords, confidence for each number, class of target). It has been signed with a 1024 bit private key, and apparently minimum message lengths are similar to the key length.
The Wikipedia article on free space laser comms has a 1 gigabit system in the article picture, though in theory laser comms work just as fast as fiber optic, minus losses due to noise.
Maybe I’m confused about the amount of overhead digital signing / verification adds to communication, but do you think that works at missile speeds? (I don’t doubt that it works at drone speeds.)
[To be clear, I’m trying to imagine the whole “distant spotter + laser transmission to missile” system, where increasing the length of messages increases the amount of time you need to have successfully targeted the missile in order to successfully transmit a message.]
Overhead is negligible because military would use symmetric cryptography. Message authentication code can be N bits for 2^-n chance of forgery. 48-96 bits is likely sweet spot and barely doubles size for even tiny messages.
Elliptic curve crypto is there if for some reason key distribution is a terrible burden. typical ECC signatures are 64 bytes (512 bits) but 48 bytes is easy and 32 bytes possible with pairing based ECC. If signature size is an issue, use asymmetric crypto to negotiate a symmetric key then use symmetric crypto for further messages with tight timing limits.
Laser links are fast. A digitally signed message can be extremely small. Suppose the message is 2048 bits with 128 bytes of payload (my cords, relative target coords, your coords, confidence for each number, class of target). It has been signed with a 1024 bit private key, and apparently minimum message lengths are similar to the key length.
The Wikipedia article on free space laser comms has a 1 gigabit system in the article picture, though in theory laser comms work just as fast as fiber optic, minus losses due to noise.
Anyways that would be 2 milliseconds.
How fast is the missile traveling?