Curious
I have read the paper and I am still a little**1 confused about how it works.
First things first, I really dislike the inherent uselessness in the BTC computations. It serves no beneficial purpose other than as an overhead in ensuring scarecity. But it does this by using frightful amounts of energy and wasting computing resources that could otherwise be used in useful pursuits (Folding / Climate Modeling / etc). At best you could call it an overhead; a necessary evil but finding something useful to do with those computations should be a high priority. Otherwise, the only people who will be able to profit from it**2 are those who run massive distributed botnets or cryptolocker malware who therefore don't need to pay input costs.
So I really WANT to like this, but there is one glaring problem that I can't see addressed. Let us assume that I agree to store X Bytes of data which is valued at a given amount Y. I can prove that I have stored X by signing some random challenges with my private key. Now I can believe a few things about all this:
* That due to the random challenge I can not predict which subset of X will be challenged.
* That due to my private key being needed to sign the challenge, I would not want to pool it in the cloud.
Now after some time, I want to sell my Y currency to buy a good/service. I am assuming that the buyer has the necessary mechanisms to prove that I am indeed the owner of the coin and the transaction goes ahead.
Now that I am no longer the owner of the coin, where is my motivation to not just wipe the data I am currently holding to realise the X Bytes of storage (or to use those same X bytes to store some other coin)? If I was to do this, there would be a coin that was not backed by the promised stored data which goes counter to the purpose of this.
How does the proposed solution prevent me from doing this? Surely I don't need to upload all of the data associated with the coin to the recipient in order to transact? Otherwise, where is the benefit in trading vs just mining fresh coins.
**1 by a little, I mean a lot.
**2 talking about mining here, not speculation; I will leave that for others to "solve".