when exchanging digital goods, how do you know somebody hasn’t sent the same asset to two people simultaneously?
use a ledger (a record of transactions) to track our trade.put our trust in this third party.we gave a copy of the ledger to every pokemon trader
if I had duplicated my card, sent one copy out earlier then tried to send the second one to you, the history of that trade would already exist, so my second trade to you would conflict and be rejected.
that digital signature that gets put on each block? That is actually generated based on the info in the block, so changing the data (i.e removing my trade) automatically changes the signature.
an open, decentralised, non-reversible, tamper-proof digital network for trading valuable assets.
This is a simplified version of how blockchain technology works, but it’s easy to see how this tech gives Bitcoin its unique and fascinating properties.
Beginning Monday, authorities are rolling out a replacement for the apparently unironically named “strong” bolivar, swapping it out for a “sovereign” bolivar that will be pegged to the government’s proposed cryptocurrency, the petro. In the process they are devaluing Venezuela’s physical currency more than 95 percent and radically weakening its exchange rate
A single U.S.-based technology company called Bitfury has been accounting for much of this mining activity, from a vast data center filled with computer servers which it opened on the outskirts of the capital Tbilisi. It has generated plenty of controversy too over claims that it received overly generous terms for its electricity bills. But scores of smaller data centers have now sprouted up, with many more people mining from home with processors bought online from China.
making an average of $800 a month mining a currency called Zcash, with the extra electricity load costing about $80.
When supporters log on to its website, they are given the choice of allowing their computer processors to be used to mine Monero, a newer virtual coin being marketed for its extreme anonymity.
Facebook groups now regularly advertise conferences and gatherings to share ideas, addressed by people who call themselves “blockchain evangelists.”
Like the original Klondike, Georgia’s digital gold rush has attracted some colorful characters hoping to make their fortune.
Take Andrew Thornhill, an energetic financial entrepreneur from Chicago and founder of a cryptocurrency startup called Spotcoin. He first came to Georgia a decade ago to provide Internet-banking advice. In 2011, he was briefly imprisoned for fraud, but he says his conviction does not restrict him from running a financial business either there or in Georgia.
Concerns that cryptocurrencies are being used as a money-laundering vehicle have been overdone, Thornhill says when we meet at Spotcoin’s Tbilisi headquarters. “Criminals are using dollars and euros every day, but we don’t blame the currencies,” he says. And blockchain technology has the potential to make financial transactions far more secure, he maintains.
Sir Jon Cunliffe, the Bank’s deputy governor for financial stability, told the BBC on Wednesday: “People need to be clear this is not an official currency. No central bank stands behind it, no government stands behind it.”
US regulators have moved towards treating some of them as currencies, whereas Korean regulators see them as commodities.
A steady stream of about 3,600 new Bitcoins are created a day – with about 16.5 million now in circulation from a maximum limit of 21 million.
Bitcoin’s Price Swings Have Been Especially Crazy in the Last 24 Hours. Here’s Why
To spell out precisely how volatile we’re talking here, it lost $1,000 in value in the space of around 10 minutes.
the IRS just got a court to back it up in its demand that Coinbase hand over details of thousands of accounts that have been high-volume bitcoin traders, so it can collect back-taxes for unreported transactions.
Vitor Constancio, the vice-president of the European Central Bank, warned on Wednesday that people should think twice about buying into bitcoin at this stage in the game.
Researchers from the universities plan to build on pioneering efforts such as MIT’s Blockcerts pilot, to create a trusted, distributed and shared infrastructure that will allow learners to:
Maintain a verifiable record of lifelong learning achievements (including badges, internships, bootcamps, certificates, MicroMasters and stackable credentials, as well as traditional degrees);
Receive credentials digitally and safely;
Share credentials with employers or other institutions;
Own their credentials forever, without having to ask or pay their institution for a transcript; and
Compile and curate credentials received from multiple educational institutions.
“Alternative digital credentials fill an important gap between learning and work-relevant skill verification. The adoption of an ADC system will allow universities to achieve greater alignment with the demands of both students and local economies, making universities more accountable for what they produce,” commented Gary W. Matkin, dean of Continuing Education and vice provost of Career Pathways at UC Irvine. “Young adults are demanding shorter, relevant education that they can put to immediate use. Industry hiring practices will increasingly depend on digital searches for job candidates and ADCs will make those competencies easier to discover.”
“Digital credentials are like tokens of social and human capital and hold tremendous value for the individual. The crucial opportunity we have today is to bring together institutions that share a commitment to the benefit of learners, and who can act as stewards of this infrastructure,” said Philipp Schmidt, director of learning innovation at the MIT Media Lab.
“Our shared vision is one where academic achievements, and the corresponding credentials that verify them, can open up new pathways for individuals to become who they want to be in the future,” said José Escamilla, director of TecLabs Learning Reimagined at Tecnologico de Monterrey.
At democracy’s heart lies a set of paradoxes: a delicate interplay of identity and anonymity, secrecy and transparency. To be sure you are eligible to vote and that you do so only once, the authorities need to know who you are. But when it comes time for you to mark a ballot, the government must guarantee your privacy and anonymity. After the fact, it also needs to provide some means for a third party to audit the election, while also preventing you from obtaining definitive proof of your choice, which could lead to vote selling or coercion.
Building a system that accomplishes all this at once — and does so securely — is challenging enough in the physical world. It’s even harder online, as the recent revelation that Russian intelligence operatives compromised voting systems in multiple states makes clear.
In the decade since the elusive Satoshi Nakamoto published an infamous white paper outlining the idea behind bitcoin, a “peer-to-peer electronic cash system” based on a mathematical “consensus mechanism,” more than 1,500 new cryptocurrencies have come into being.
definition: Nathan Heller in the New Yorker, in which he compares the blockchain to a scarf knit with a single ball of yarn. “It’s impossible to remove part of the fabric, or to substitute a swatch, without leaving some trace,” Heller wrote. Typically, blockchains are created by a set of stakeholders working to achieve consensus at every step, so it might be even more apt to picture a knitting collective creating that single scarf together, moving forward only when a majority agrees that a given knot is acceptable.
Unlike bitcoin, a public blockchain powered by thousands of miners around the world, most voting systems, including Votem’s, employ what’s known as a “permissioned ledger,” in which a handful of approved groups (political parties, election observers, government entities) would be allowed to validate the transactions.
there’s the issue of targeted denial-of-service (DoS) attacks, in which a hacker directs so much traffic at a server that it’s overwhelmed and ceases to function.
Although a distributed ledger itself would likely withstand such an attack, the rest of the system — from voters’ personal devices to the many servers a vote would pass through on its way to the blockchain — would remain vulnerable.
there’s the so-called penetration attack, like the University of Michigan incursion, in which an adversary gains control of a server and deliberately alters the outcome of an election.
While it’s true that information recorded on a blockchain cannot be changed, a determined hacker might well find another way to disrupt the process. Bitcoin itself has never been hacked, for instance, but numerous bitcoin “wallets” have been, resulting in billions of dollars in losses. In early June 2018, a South Korean cryptocurrency exchange was penetrated, causing the value of bitcoin to tumble and resulting in a loss of $42 billion in market value. So although recording the vote tally on a blockchain introduces a new obstacle to penetration attacks, it still leaves holes elsewhere in the system — like putting a new lock on your front door but leaving your basement windows open.
A blockchain is only as valuable as the data stored on it. And whereas traditional paper ballots preserve an indelible record of the actual intent of each voter, digital votes “don’t produce an original hard-copy record of any kind,”
In the end, democracy always depends on a certain leap of faith, and faith can never be reduced to a mathematical formula. The Economist Intelligence Unit regularly ranks the world’s most democratic counties. In 2017, the United States came in 21st place, after Uruguay and Malta. Meanwhile, it’s now widely believed that John F. Kennedy owed his 1960 win to election tampering in Chicago. The Supreme Court decision granting the presidency to George W. Bush rather than calling a do-over — despite Al Gore’s popular-vote win — still seems iffy. Significant doubts remain about the 2016 presidential race.
While little doubt remains that Russia favored Trump in the 2016 election, the Kremlin’s primary target appears to have been our trust in the system itself. So if the blockchain’s trendy allure can bolster trust in American democracy, maybe that’s a net positive for our national security. If someone manages to hack the system, hopefully they’ll do so quietly. Apologies to George Orwell, but sometimes ignorance really is strength.
The main thing distinguishing a blockchain from a normal database is that there are specific rules about how to put data into the database. That is, it cannot conflict with some other data that’s already in the database (consistent), it’s append-only (immutable), and the data itself is locked to an owner (ownable), it’s replicable and available. Finally, everyone agrees on what the state of the things in the database are (canonical) without a central party (decentralized).
It is this last point that really is the holy grail of blockchain. Decentralization is very attractive because it implies there is no single point of failure.
The Cost of Blockchains
Development is stricter and slower
Incentive structures are difficult to design
Maintenance is very costly
Users are sovereign
All upgrades are voluntary
Scaling is really hard
Centralization is a lot easier
Like it or not, the word “blockchain” has taken on a life of its own. Very few people actually understand what it is, but want to appear hip so use these words as a way to sound more intelligent. Just like “cloud” means someone else’s computer and “AI” means a tweaked algorithm, “blockchain” in this context means a slow, expensive database.“blockchain” is really just a way to get rid of the heavy apparatus of government regulation. This is overselling what blockchain can do. Blockchain doesn’t magically take away human conflict.
So what is blockchain good for?
Most industries require new features or upgrades and the freedom to change and expand as necessary. Given that blockchains are hard to upgrade, hard to change and hard to scale, most industries don’t have much use for a blockchain. a lot of companies looking to use the blockchain are not really wanting a blockchain at all, but rather IT upgrades to their particular industry. This is all well and good, but using the word “blockchain” to get there is dishonest and overselling its capability.