字幕表 動画を再生する 英語字幕をプリント If you're a modern criminal, chances are you've used it to buy guns, drugs and even launder money. Sounds dodgy. But high profile institutions such as USAID and UNICEF have a different view. They think it could be a force for good, helping the poorest people in the world. What is blockchain? It's a technology called blockchain - a global online database that anyone, anywhere with an internet connection can use. Unlike traditional databases, which are owned by central figures like banks and governments, a blockchain doesn't belong to anyone. And with an entire network looking after it, cheating the system by faking documents, transactions and other information becomes near impossible. Here's how it works. Blockchains store information permanently across a network of personal computers. This not only decentralizes the information, but distributes it too. So how can a multi-purpose online database, whose users include criminals, work for everyday use? How does it stay relatively hack-proof? The answer is blockchain's millions of users. They make it difficult for any one person to take down the network or corrupt it. The many people who run the system use their own personal computers to hold bundles of records submitted by others. The records are known as blocks. Each block has a timestamp and a link to a previous block, forming a chronological chain. It's like a giant Google doc with one key difference. You can view it and add to it, but you can't change the information that's already there. The blockchain enforces this by using a form of math called cryptography, which means records can't be counterfeited or altered by someone else. Blockchain's most famous application is Bitcoin. It's a digital currency that is created and held electronically - and you can send it to anyone, whether you know them or not. Bitcoin provides a level of anonymity not seen in modern times. That's because unlike credit cards or PayPal payments, there are no middlemen such as banks or financial institutions asking for our personal information and home address. Instead people from all over the world move the digital money by validating other people's Bitcoin transactions, earning a small fee in the process. Where the blockchain comes in is verifying the ownership of this digital cash and making sure only one person is claiming it as their own at a time. Banks and businesses are rushing to adopt blockchain database technology. In a survey of 308 senior executives at U.S. companies with $500 million or more in annual revenue, Deloitte found that 28 percent of respondents had invested $5 million or more in blockchain technology. 10 percent had invested $10 million or more. But why are they spending so much money? Well, to save money of course. When this study looked into the data of eight of the world's largest investment banks, it found that blockchain could save them $8 to $12 billion dollars every year. Bet that $5 million investment doesn't sound so bad now. But it's not all good news for the big players, of course. Blockchain lowers the barrier for entry into the banking industry, and that means fintech startups are popping up in pretty much every market they operate in. If banks and companies can't keep up, they're putting their own survival at risk. For the consumer, the future seems brighter with more security, less cost and better experiences. Yet, blockchain could be the biggest game changer for the poorest in society. The technology is open to people living in low income countries or fragile states at risk of economic collapse. Take a farmer with a small plot of land which is then flooded. The paper copy of the deeds to his land is washed away, resulting in the farmer having no proof of owning the land. Or perhaps he does have a digital copy on a government database but it is erased, altered or even destroyed in a political coup. If the farmer had filed that deed on a blockchain, he could have avoided all these problems. Along with speeding up the flow of cash and providing a secure place to keep records - the benefits for the poorest in society are enormous. From protecting our identities to running autonomous vehicles to managing a world that is increasingly dependent on the internet of things, the possibilities for blockchain technology seem endless. But whether it lives up to its promise remains to be seen.