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Or you can use the strengths of cryptocurrency and split a key between a safe deposit box, your home, and yourself, and require 2 of 3 of them to get the origin
by Klathmon 9y ago
Or you can use the strengths of cryptocurrency and split a key between a safe deposit box, your home, and yourself, and require 2 of 3 of them to get the original key.
- frikk 9y agoThat's a neat idea. Do you mind expanding on it?
- solotronics 9y agoit's called 2 of 3 multisig and it's a standardized part of most cryotocurrency. it requires X of Y separate key signings to complete a transaction from an address
- MichaelGG 9y agoShamir's Secret Sharing allows this even without dealing with multisig wallets.
- Klathmon 9y agoThis is what I had in mind. And it can scale to any "n of m" you want, without any if the downsides if multisig wallets (namely larger transactions, and more complex Bitcoin wallets required) 2 of 2, 3 of 5, 7 of 10, etc...
- DennisP 9y agoI like the idea but I wish there were a widely-trusted implementation with public security reviews, maybe built into wallet software.
- Klathmon 9y agoIt's not a terribly large amount of code, and it's easy to test, even with a "live" key (since testing that any n of m can be recombined doesn't force a spend or reveal anything externally). Also, it's a fairly well-known system, so I don't see it being collectively "forgotten" on the timescale of a few decades (it's been around since the late 70's i believe). I'd love to get it integrated into wallet software, as it's such a safe and reliable way of storing secrets that lets you be as "secure" or as "reliable" as you want with just a slider.
- jondwillis 9y agoYou could take a private key and split it into three parts and store them separately.
- cm2187 9y agoYou should rather xor it with two other random keys.
- arde 9y agoI don't think I follow you, could you please explain what you mean a bit further?
- cm2187 9y agoYou don’t really want to split the key (as in if the key is n bytes, split it in 3 segments of n/3 bytes) because if one has two segments, I imagine it’s not inconceivable to infer the third segment from the public key and the other two (though I haven’t made the math). Rather you have a private key p of n bytes. Create two cryptographically random keys k1 and k2 of n bytes each. Derive a key k3=(p XOR k1) XOR k2. k1, k2 and k3 are your distributed keys. To recompute p you need to do p = (k3 XOR k2) XOR k1. A XOR is trivial to implement and I would expect be reasonably robust.
- tehlike 9y agosplitting the key into multiple segments reduces the number of bits one has to guess.
- DennisP 9y agoThat definitely helps against many scenarios, but "home and yourself" means you're still in immediate control of funds while you're at home, so you're still vulnerable to armed robbery. You want to make it so your answer to the robber is "I can't, the bank's not open."
- Klathmon 9y agoThen make it 3 of 3, it all depends on your threat model. For me, my biggest threat is loss, followed by theft, so it makes sense to have some redundancy even if it means reducing the security against theft.
- damontal 9y agoAnd then what? The robber who went through the trouble of breaking in and demanding your money will apologize and see himself out?
- deleted 9y ago[deleted]
- DennisP 9y agoIf you had a large number of gold coins, would you keep them at home to avoid annoying robbers?