"Online Only- I don’t think there is a solution to this criticism, but not sure what the issue is."
The fact that I need to connect to some peer-to-peer network or third party service for every transaction is a limiting factor. It reduces the efficiency of the system and increases latency, and it adds additional points of failure.
In fact it can be solved for electronic transactions and there is a mountain of published research on the topic that dates back to the late 80s. Here is a recent research paper:
The idea is to ensure that users who attempt to double spend can be identified and penalized later (e.g. by being added to a blacklist; some systems actually ensure that all transactions in which the cheating user participated can be identified, so merchants who try to evade the blacklist can also be penalized). The money has to be issued by a bank under the security definition. If anonymity is not a requirement -- and presumably a Bitcoin enthusiast does not care about anonymity since Bitcoin is not anonymous -- this can be easily achieved by using ordinary digital signatures.
I think you are not understanding how bitcoin works, and this exact problem of double spending was better solved by bitcoin. You dont need to trust a third oarty or “online service”, you can dimply run a bitcoin node. If it is that important a raspberry pi and SSD is cheaper than your average credit card terminal.
The credit card network, by the way, is much worse in this regard.
...so you need to be online, connected to the rest of the Bitcoin peer-to-peer network, to engage in a transaction. I am talking about offline transactions, where I only need to communicate with the other party in the transaction. Again, you can just read the paper I gave a link to, which describes this scenario, or any of the other hundreds of papers published on the topic.
Unlike many great ideas, those in the paper you cite just haven't yet gathered enough acceptance.
The value of the US dollar as a reserve currency is a faith-based article, and yet it works well. The confidence in the Fed to not unduly dilute the value has reinforced the resolve of the participants to continue to accept it as currency.
Bitcoin's paid many years of dues in this regard as well, and its garnered the confidence of its market participants despite its deficiencies.
The fact that I need to connect to some peer-to-peer network or third party service for every transaction is a limiting factor. It reduces the efficiency of the system and increases latency, and it adds additional points of failure.
In fact it can be solved for electronic transactions and there is a mountain of published research on the topic that dates back to the late 80s. Here is a recent research paper:
https://eprint.iacr.org/2017/1220.pdf
The idea is to ensure that users who attempt to double spend can be identified and penalized later (e.g. by being added to a blacklist; some systems actually ensure that all transactions in which the cheating user participated can be identified, so merchants who try to evade the blacklist can also be penalized). The money has to be issued by a bank under the security definition. If anonymity is not a requirement -- and presumably a Bitcoin enthusiast does not care about anonymity since Bitcoin is not anonymous -- this can be easily achieved by using ordinary digital signatures.