alt Hacker NewsSo these messages are presumably encrypted with a one time pad, and some lookup book of what each message of just a few characters means?
And I assume there are also a high bandwidth comms channels, and this is just the backup which is presumably tested each day.
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Some of the comms channels are even lower bandwidth: https://en.wikipedia.org/wiki/Extremely_low_frequency (Though, apparently the US no longer uses this)
I think this is the primary.
High bandwidth comms are likely a lot more fragile than this. At the same time: there will be many different transmission channels, and I would expect this one to be useless immediately if someone really did something nasty.
You can probably just point Claude or ChatGPT to decrypt it, it would find that there's some silly and obvious cipher is used that survived from the 60ies, with a 56 bit private key. /this is a wild guess, I don't have any special clearance or access/
Nuclear strike orders do not require high bandwidth. The orders contain targeting information and arming codes, all of which is pre-programmed on the missiles (the target package is specified with a "pointer" -- the computers on the missiles already have all the details, the order simply identifies which set of details should be used). For ICBM crews it is conceivable that orders could be transmitted on high-bandwidth systems, but for submarines that is not even possible (ELF bands have to be used because of the physical properties of ocean water).
The basic launch sequence is this: a missile crew receives a series of characters and both missileers write the characters down. They check against a codebook and verify that they both heard the same message and that it is a valid launch order. If the message is valid, they unlock the launch keys (from a box secured by two combination locks, each missileer knows the combination for one lock), insert the keys, enter the missile launch unlock code, enter the warhead arming code, turn the keys, and then that's that.
(There are several other steps -- go watch a video of a test launch and listen to the operators read off the checklist, there are quite a few steps. If you are wondering why such information is public, it is meant to reassure the other side that there is no possibility of unauthorized or unintentional launches -- we want our adversaries to know how we control our nuclear forces so they don't panic and preemptively attack us)