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giovedì 1 agosto 2024
sabato 14 dicembre 2019
COMPRARE BITCOIN?
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sabato 29 giugno 2019
IL SUCCESSO DELLE CRIPTOVALUTE
martedì 6 febbraio 2018
Male che produce bene
domenica 24 dicembre 2017
La stabilità del Bitcoin
Difficile utilizzare il Bitcoin come moneta di pagamento. Innanzitutto, ci sono altri costi di transazione.
Poi il Bitcoin non è stabile.
In teoria, però, una criptovaluta stabile è possibile. Il Basecoin costituisce il tentativo di costruirne una.
Il Dollaro di Hong Kong è agganciato al Dollaro statunitense. Anche una moneta elettronica può essere trattato nello stesso modo. In alternativa può essere agganciata ad un paniere di beni.
I precedenti del Bitcoin garantivano la massima sicurezza ma richiedevano un emittente. L'avversione dei governi impediva di trovare i emittenti affidabili.
Il bello del Bitcoin e che non esiste alcun emittente è così il problema precedente si dissolve.
Ma come funziona il Basecoin? C'è un software che emette monete sulla base di una parità da rispettare, per esempio quella con il dollaro. La moneta emessa E spesa da uno dei tanti emittenti virtuali. In caso contrario la moneta viene ritirata sempre agli stessi soggetti.
lunedì 5 giugno 2017
ECASH SAGGIO
One is that a seller does not have to know anything about me in order to accept cash. That makes money a better medium for transactions with strangers,
better medium for small transactions, since using cash avoids the fixed costs
money leaves no paper trail, which is useful not only for criminals but for anyone who wants to protect his privacy
The advantage of money is greater in cyberspace, since transactions with strangers,
The disadvantage is less, since my ecash would be stored inside my computer,
Despite its potential usefulness, there is as yet no equivalent of cash available online
The reason is in part the hostility of governments to competition in the money business
There is a simple solution to this problem - so simple that I am surprised it is not yet in common use. The solution is to put a price on your mailbox.
Give your email program a list of the people you wish to receive mail from. Mail from anyone not on the list is returned with a note explaining that you charge five cents to read mail from strangers - and the URL of the stamp machine. Five cents is a trivial cost to anyone with something to say
The stamp machine is located on a web page. The stamps are digital cash. Pay $10 from your credit card and you get in exchange 200 five-cent stamps - each a morsel of encrypted information that you can transfer to someone else who can in turn transfer it… If lots of strangers choose to send me messages, I can accumulate a surplus…
What is in it for the stamp machine - why would someone maintain such a system? Part of the answer is seigniorage
If your stamps are popular, many of them may stay in circulation for a long time - leaving the money that bought them in your bank account accumulating interest.
One reason this solution to spam requires ecash is that it involves a large number of very small payments.
The solution is a digital signature.
When he receives the file he checks the digital signature against the bank's public key.
Sending a copy of the file in payment for one transaction does not erase it from your computer
One solution is for the bank to give each dollar its own identification number and keep track of which ones have been spent.
This solves the problem of double spending, but it also eliminates most of the advantages of ecash over credit cards. The bank knows that it issued banknote 94602... to Alice
The solution to this problem uses what David Chaum, the Dutch cryptographer who is responsible for many of the ideas underlying ecash, calls blind signatures.
Curious readers will want to know how it is possible for a bank to sign a serial number without knowing what it is. I cannot tell them without first explaining the mathematics of public key encryption …
Random numbers, checks of digital signatures, blind signing, and all the rest are done in the background… how little most of us know about how the tools we routinely use, such as cars, computers, or radios, actually work.
What motivated him was the problem we discussed back in Chapter 4 - the loss of privacy created by the ability of modern information processing to combine publicly available information into a detailed portrait of each individual.
It would be very convenient if, instead of stopping at a toll booth when getting on or off the interstate, we could simply drive past, making the payment automatically
One problem is privacy. If the payment is made with a credit card, or if the toll agency adds up each month's tolls and sends you a bill, someone has a complete record of every trip you have taken on the toll road, every time you have crossed a toll bridge.
Ecash solves that problem. As you whiz past the tollbooth, your car pays it fifty cents in anonymous ecash. By the time you are thirty feet down the road, the (online) tollbooth has checked that the money is good; if it isn't an alarm goes off, a camera triggers, and if you do not stop a traffic cop eventually appears on your tail.
It works for shopping as well. Ecash - this time encoded in a smart card in your wallet,
My examples so far assume that ecash will be produced and redeemed by private banks but denominated in government money.
any ecash expected to circulate widely will be issued by organizations with reputations.
Some economists, in rejecting the idea of private money, have argued that such an institution is inherently inflationary.
The rebuttal to this particular argument was published in 1776. When Adam Smith wrote The Wealth of Nations, the money of Scotland consisted largely of banknotes issued by private banks, redeemable in silver.' As Smith pointed out, while a bank could print as many notes as it wished, it could not persuade other people to hold an unlimited number of its notes.
The obligation of the bank to redeem its money guarantees its value… So far I have assumed that future ecash will be denominated in dollars… Dollars have one great advantage - they provide a common unit already in widespread use. They also have one great disadvantage - they are produced by a government, and it may not always be in the interest of that government to maintain their value in a stable…
Dollars have a second disadvantage, although perhaps a less serious one. Because they are issued by a particular government, citizens of other governments may prefer not to use them.
If large amounts of gold are discovered or if someone invents new and better techniques for extracting gold from low-grade ore, the value of gold, and of gold-based money, will decline.2
That problem is solved by replacing a simple commodity standard with a commodity bundle.
getting all the firms issuing ecash to agree on the same bundle. If they fail to establish a common standard, we end up with a cyberspace in which different people use different currencies and the exchange rates between them vary randomly. That is not an unworkable situation - Europeans lived with it for a very long time - but it is a nuisance. Life is easier if the money I use is the same as the money used by the people I do business with.
A system of multiple monopoly government moneys works less well in cyberspace because in cyberspace national borders are transparent… The obvious solution is to establish a single standard of value, either by adopting one national currency, probably the dollar, possibly the euro, or by establishing a private standard such as the sort of commodity bundle described earlier… The reason that everyone wants to use the same currency as his neighbors is that currency conversion is a nuisance. But currency conversion is arithmetic and computers do arithmetic fast and cheap. Perhaps, with some minor improvements in the interfaces on which we do online business, we could make the choice of currency irrelevant, permitting multiple standards to coexist.
As I write, the countries of Europe are in the final stages of replacing their multiple national currencies with the euro. If the picture I have just painted turns out to be correct, they may have finally achieved a common currency just as it was becoming unnecessary.
Chaum himself, working with the Mark Twain Bank of Saint Louis, attempted to get a semi-anonymous ecash into circulation - one that permitted one party to a transaction to be identified by joint action of the other party and the bank. The effort failed and was abandoned. One reason it has not happened is that online commerce has only very recently become large enough to justify it.
A second reason, I suspect but cannot prove, is that national governments are unhappy with the idea of a widely used money that they cannot control
A third and closely related reason is that a truly anonymous ecash would eliminate a profitable form of law enforcement…. There is no practical way to enforce money-laundering laws
A final reason is that ecash is only useful to me if many other people are using it, which raises a problem in getting it started.