Great idea. If the assumption is that only a handful of keys will be needed pet year, it is much less expensive to require the government to brute force a key solution than storing and securing all the keys.
Just choose a key strength that costs about $10,000,000 to brute force it, and keep increasing key strength as more efficient methods are found.
Just choose a key strength that costs about $10,000,000 to brute force it, and keep increasing key strength as more efficient methods are found.