This week's half-baked proposal: hash cash keys, an extensions of SSKs where the key includes an extra field, b, and the data must be accompanied by a string whose hash shares a b-bit prefix with the hash of the public part of the key. Nodes check the partial hash collision before forwarding or storing the data; the string is forwarded and stored with the data.
The key is written in the form SSK.b at foo,bar/baz, for example SSK.32 at foo,bar/baz for a 32-bit collision. This is for backwards compatibility with KSKs: you can't put b after the @ sign because everything after the @ sign is part of the name. This should make it pretty trivial to add hash cash to Frost: just use KSK.32 (for example) instead of KSK for new messages, and stop checking the old KSK queues after a transition period of a week or two. The value of b can be increased over time as computers get faster. I'm probably missing something obvious here - anyone care to point out what it is? :-) Cheers, Michael
