[CydeWeys]

I've been using central ledger currency systems (i.e. logging into my bank's website and issuing payments) for longer than Bitcoin has existed. Decentralization is the entire point of Bitcoin. Take that away and you aren't left with anything that wasn't already done long ago. What you're proposing is something that banks have already been doing widely for decades.

[xigency]

> Take that away and you aren't left with anything that wasn't already done long ago

And that is exactly my point. There are very interesting ideas in digital currencies/digital cash that have no representation in Bitcoin or at all.

By using Bitcoin, like using your bank's website, you still need an Internet connection to use your currency digitally.

However, it's possible to create a digital currency that doesn't have to be plugged-in to a network to operate. Being able to send an e-mail with a cash value integrated in its data is something that hasn't been done long ago, or even yet today.

Even better, some digital currencies could (conceptually) be sent in a paper letter as cash.

Whether the value is created algorithmically or by bankers is a separate, economic debate, and really less interesting, in my opinion, than the technology itself.

[CydeWeys]

> By using Bitcoin, like using your bank's website, you still need an Internet connection to use your currency digitally.

You can do all sorts of things with Bitcoin without needing to be attached to a network. You can have an address that has value associated with it and then print a private key as physical Bitcoin -- variants that have been done include coins, bills, paper wallets, and OCR-able backups of regular wallets. In a high security situation you can have Bitcoin running on an offline computer and sneakernet signed transactions from it to avoid ever exposing it to the Internet.

> However, it's possible to create a digital currency that doesn't have to be plugged-in to a network to operate.

Yes, like all of the above.

> Being able to send an e-mail with a cash value integrated in its data is something that hasn't been done long ago, or even yet today.

You lost me. How does email work without being attached to a network?! If you're giving us access to a network, why not just use Bitcoin? If you meant something like snail mail, well then, again, see above.

> Even better, some digital currencies could (conceptually) be sent in a paper letter as cash.

Yes. Like Bitcoin.

Or are you truly trying to propose some kind of digital currency that never requires network access? How could that possibly work? If network access isn't allowed, how do I know that you haven't already sent the same "digital coin" that you're sending me to ten other people? The double spend problem is real. Bitcoin solves it. I don't see how a solution is possible that doesn't involve some kind of communication.

[xigency]

Digital implies something that is based in information, which doesn't imply a computer network. I won't pretend to be an expert, and I might have been living under a rock concerning Bitcoin, as it is not something I use.

The article link I posted (for a research paper, second level post), plus the original sources and works that cite it specifically discuss digital or cryptographic cash which follow six properties, including anonymity and some measures of usefulness.

Bitcoin achieves this, but it's also possible to achieve with a central authority or coalition of authorities. Interestingly, the consequence of double payment or false payments is to have one's identity revealed or to effectively assume debt. The fraudulent charges are exposed as IOUs.

The proof of work portion of Bitcoin, which I think is bothersome and wasteful, is related to the money supply. If a currency were tied to real funds or precious metals some of the burden would be lifted, but a large database would still be required.

[CydeWeys]

Let me try to explain by way of analogy.

Using a blockchain to implement a trustless distributed ledger is such a fundamentally important revolution in digital currencies that you can compare it to what Einstein's theory of relativity did for physics. They both caused complete sea changes in their fields. Citing a paper from the early 1990s on digital currency is like citing a paper on physics from the 1800s in a technical discussion about GPS.

I am not being hyperbolic. I realize what it may sound like, but solving the double-spend problem without a central authority was the tricky issue in digital currencies that vexed computer scientists for decades. Bitcoin solved it. The double spend problem falls under the category of (b) from the paper that you cited, and note that said paper does not solve it.

If you are at all interested in digital currencies, and it sounds like you definitely are, then you owe it to yourself to read up on Bitcoin, to understand how it works, and to understand the problems that it solves. There has been a huge explosion in the field since the release of Satoshi Nakamoto's original whitepaper.

To answer some minor points:

> Bitcoin achieves this, but it's also possible to achieve with a central authority or coalition of authorities.

This has been possible for thousands of years. You just have a central ledger that is locked up and inaccessible somewhere. That's how all existing banking systems work. I'm not sure why you keep bringing this up; it's not relevant because it doesn't solve the problem that Bitcoin does. Saying that it can be done with a central authority is like telling Gugliemo Marconi that he can make contact with the other receiver if he just lays a wire between the two. Yes, it's true, but it misses the point entirely; he was trying to invent wireless communication, not create yet another telegraph system (which had already been around for decades).

> Interestingly, the consequence of double payment or false payments is to have one's identity revealed or to effectively assume debt.

Bitcoin allows strong pseudonymity while maintaining protection against double spends, while subsequent iterations of it building on the blockchain idea allow for strong anonymity (see Darksend).

> The proof of work portion of Bitcoin, which I think is bothersome and wasteful, is related to the money supply.

The proof of work portion is required to implement a system that has the properties that Bitcoin has. Relativity is tricky and hurts my brain, but if I want to make a GPS satellite that works, I have to use it.

[xigency]

> Citing a paper from the early 1990s on digital currency is like citing a paper on physics from the 1800s in a technical discussion about GPS.

Like Maxwell's equations?

Anyway, for (b) security it claims to be secure by providing a way for the bank A to reveal the identity P of the double-spender mathematically from the duplicate spent coins.

I agree that these ideas solve different issues.

Bitcoin is set up for making payments to individuals far away and anonymously (or pseudo anonymously). This makes it possible to say, order a pizza with Bitcoin. By the time the pizza is done being made it's possible for the merchant to verify the transaction. Completing a transaction on the sneakernet would be akin to carbon-copying a credit card when the network is down.

These other digital currency ideas are different and seem easier to implement for making a purchase at 7 Eleven and leaving within 10 seconds or making purchases without a network and knowing that the value is there.

Yes, it requires banks, like checkbooks require banks, but a digital currency can offer some benefits that paper checks don't, and it shows that Bitcoin has limitations. The drawback would be negotiating an agreement with a financial institution.

In terms of the article, Bitcoin makes it very easy to lose money, especially if someone loses their private key.

[CydeWeys]

> Like Maxwell's equations?

Maxwell's equations don't yield workable GPS. You need general relativity. Similarly, you need a blockchain (or some similar solution for the double-spend problem) for a workable digital currency.

> Anyway, for (b) security it claims to be secure by providing a way for the bank A to reveal the identity P of the double-spender mathematically from the duplicate spent coins.

Yes, exactly, it needs a centralized authority (the bank). You're citing a digital currency scheme that was never workable enough to be implemented and that was state of the art 25 years ago, which is an eternity in the world of digital currencies. Can we please talk about what's state of the art today?

> These other digital currency ideas are different and seem easier to implement for making a purchase at 7 Eleven and leaving within 10 seconds or making purchases without a network and knowing that the value is there.

... umm, like a credit card? That solves your use case of being able to pay for it quickly. It's also been around for decades. Or for something that works when the network is down, how about a simple smart card, like that can be used to pay for bus rides? Again, decades-old technology. Not revolutionary now. Still requires a centralized authority. You're talking about long-solved problems.

If you want to do it with no central authority, which is the key thing, then now we need to use blockchain technology. If you're willing to accept the low risk inherent in 0-conf transactions, you can use Bitcoin for your theoretical "buy something cheap at 7-11 in 10 seconds" use case. If you want to reduce risk further, you can use Lightning Network or similar, which is a further evolution on Bitcoin that does allow ironclad sub-second confirmations. I highly suggest that you look into it. It sounds like what you are most interested in.

I don't know how else to make this important fact clear to you: If you have a centralized authority, then there's nothing new under the Sun, and it's all possible with decades-old technology. It's not really a digital currency though, it's just a method for moving entries around in a centralized digital ledger. It requires trust in banks and governments. Decentralized digital currencies like Bitcoin require only trust in math. This is a huge difference in kind, not degree, but you keep suggesting schemes that don't even have this important property. I get that you don't think it's important, but at least maybe try to understand it?

[Andrew_Quentin]

Problem is that if it was centralized it may be shut down. Moreover, the central entity would have to issue money and comply with aml etc and register accounts, thus turning it into a bank.