블록체인의 이해 트랜잭션, 보안 및 애플리케이션

### 블록체인의 이해: 트랜잭션의 미래와 실제 애플리케이션
* 💡 블록체인 기술은 **온라인 지갑, 은행 또는 타사 애플리케이션의 번거로움 없이 거래를 원활하게 완료**할 수 있는 방법을 제공합니다.
* 🍽 친구들이 저녁 식사 비용을 나눠 내는 시나리오에서 잭은 **은행 거래 실패 경험**을 통해 **기술적 결함이나 이체 한도** 등 기존 은행 거래의 잠재적 문제를 강조합니다.
* 💰 블록체인 기술을 기반으로 작동하는 암호화폐의 등장은 **안전하고 분산된 거래 방식**을 제공함으로써 이러한 은행 업무의 문제를 해결합니다.
* 🔗 블록체인의 각 거래는 **블록에 영구적인 기록**을 생성하여 사용자 간에 공유되는 공개 분산 원장을 형성하고 투명성과 보안을 보장합니다.
* 🔒 고유한 공개 키와 개인 키를 사용하여 거래 데이터를 암호화하면 무단 액세스 및 변경을 방지하여 **해킹에 강한 블록체인**을 만들 수 있습니다.
* ⛏ 채굴자는 작업 증명이라는 과정을 통해 거래를 검증하고, 복잡한 수학 문제를 해결하여 블록체인에 블록을 추가하며, 노력에 대한 보상으로 **12.5비트코인**과 같은 보상을 받습니다.
* 🏬 월마트와 같은 기업은 블록체인을 활용하여 공급망 전반에서 제품 품질을 추적함으로써 **반품 및 환불로 이어지는 문제를 신속하게 파악**하고 해결할 수 있습니다.
* 📝 블록체인이 계속 발전함에 따라 그 응용 분야가 확대되고 있으며, **금융을 넘어 다양한 산업에서 블록체인의 잠재적 활용에 대한 논의**가 활발해지고 있습니다.

블록체인 기술은 은행이나 타사 애플리케이션에 의존하지 않고도 안전하고 투명한 거래를 가능하게 합니다.

ever wonder if there's an easier way to complete transactions without having to deal with online wallets, banks, and third-party applications? Well, it's possible thanks to blockchain. Here's everything you need to know about blockchain. Imagine four friends: Jack, Ted, Sam, and Phil meet up for dinner. After they're done, Jack pays the bill, and all of them decide to split the expense amongst each other. Now, on the next day when Phil sends his share to Jack via online money transfer, the transaction goes through without a hitch. Then Ted and Sam send their respective shares to Jack, but their transactions don't go through. The failed transaction cites some issues at the bank. That's when Jack comes to know about the many ways a bank transaction could fail. It could be due to technical issues at the bank, one of their accounts being hacked, daily transfer limits being exceeded, and sometimes additional charges like transfer charges associated with transferring money. To solve these problems, the concept of cryptocurrency came into existence. Cryptocurrencies are a form of digital or virtual currency that run on a technology known as

blockchain. Thanks to blockchain, cryptocurrencies are immune to counterfeiting, don't require a central authority, and are protected by strong and complex encryption algorithms. In a market of more than thousands of cryptocurrencies like Litecoin, Ethereum, Zcash, and so on, one reigns supreme: Bitcoin. Now let's go back to our previous example and have Phil, Ted, and Sam send Jack two bitcoins each as their contribution to the previous night's dinner. Let's assume Phil, Ted, and Sam have three bitcoins in reserve while Jack has five. First, Phil sends two bitcoins to Jack. A record is created in the form of a block. The transaction details between them are permanently inscribed in this block. This record also holds the number of bitcoins each of the friends owns. So, after Phil's transaction, Jack has seven bitcoins while Phil has one. Following this, Sam and Ted send two bitcoins to Jack. A new block is created for each of these transactions. These blocks hold the transaction details as well as how many bitcoins Sam, Ted, and Jack have in reserve. These blocks are

linked to each other, as each of them takes reference from the previous one for the number of bitcoins each brand owns. This chain of records or blocks is called a ledger, and this ledger is shared among all the friends, which acts as a public distributed ledger. This forms the basis of blockchain. So, what happens when Phil has only one bitcoin left and he tries to send two more bitcoins to Jack? The transaction will not go through. This is because all his friends have copies of the ledger, and it's clear that Phil has only one bitcoin left. His friends will flag this transaction as invalid. A hacker will not be able to alter the data in the blockchain because each user has a copy of the ledger. The data within the blocks are encrypted by complex algorithms. All of this is made possible with the help of blockchain technology. Blockchain can be described as a collection of records linked with each other, strongly resistant to alteration, and protected using cryptography. Now, let's have a closer look at the bitcoin transaction between Jack and Phil and find out how.

It works. Every user in the bitcoin network has two keys: a public key and a private key. The public key is an address that everyone in the network knows of, like an email address of a user. The private key is a unique address that only the user has knowledge of, something like a password. First, Phil passes the number of bitcoins he wants to send to Jack, along with his and Jack's unique wallet address, through a hashing algorithm. All of this is part of the transaction details. These details are encrypted using encryption algorithms and using Phil's unique private key. This is done to digitally sign the transaction and to indicate that the transactions came from Phil. This output is now transmitted across the world using Jack's public key. With this, the message or transaction can be decrypted only by Jack's private key, which only Jack has knowledge of. Different cryptocurrencies use different hashing algorithms. While Bitcoin uses the SHA-256 algorithm, Ethereum, which is also a famous cryptocurrency, uses one known as Ethash. This transaction and several other similar ones are taking place all around the world. These transactions are

validated and then added block by block. The people who validate these blocks are called miners. For a block to be validated and added to a blockchain, miners need to solve a complex mathematical problem. The miner who solves this first adds the block to the blockchain and is rewarded with 12.5 bitcoins. The process of solving the complex mathematical problem is called proof of work, and the process of adding a block to the blockchain is called mining. With this, Phil and Jack's wallets are updated, just like every person in the network who has completed a transaction. Now that you know about blockchain and its important concepts, time for a small quiz. What is the concept of blockchain that ensures data cannot be altered by any of the users within the network? a) public distributed ledger b) proof of work c) proof of stake d) hash encryption. Let us know what you think is the right answer in the comments below. Three lucky winners will get Amazon gift vouchers. Details are mentioned in the description below. Let's have a look at how Walmart uses blockchain to provide its customers with

better service. Walmart was facing problems in delivering quality products to its customers. They were facing a high return rate and large amounts of refunds due to their products' bad quality. They were unable to determine the point of failure in the supply chain, which started from farm to storage to transportation to processing, all the way to the customer. Then Walmart adopted blockchain technology. With blockchain, the quality of the goods at each step was permanently inscribed within a block. For example, when a customer flags a product as damaged, it can be correctly identified where the product got damaged in the entire supply chain, thus helping Walmart to identify the problem areas and fixing them. And this is just one of several ways blockchain is used in real-life applications. Can you think of any others? Let us know in the comments down below. That's all for now. Thank you for watching and stay tuned for more.

Blockchain In 7 Minutes | What Is Blockchain | Blockchain Explained|How Blockchain Works|Simplilearn

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블록체인 기술은 은행과 온라인 지갑에서 흔히 발생하는 거래 실패에 대한 해결책을 제시합니다.

블록체인에서 운영되는 암호화폐는 위조에 영향을 받지 않으며 중앙 기관이 필요하지 않습니다.

비트코인은 거래 및 소유권 기록이 블록에 영구적으로 새겨지는 가장 지배적인 암호화폐입니다.

비트코인 거래는 모든 사용자가 공유하는 공개 분산 원장, 즉 블록체인에 기록됩니다.

각 사용자는 공개 키와 개인 키를 가지고 있으며, 공개 키는 거래의 주소 역할을 하고 개인 키는 고유한 액세스 권한을 제공합니다.

거래는 발신자의 개인 키를 사용하여 암호화되고 디지털 서명되며, 출력은 수신자의 공개 키를 사용하여 전송되므로 안전하고 검증된 전송을 보장합니다.

채굴자는 복잡한 수학 문제를 풀면서 블록을 검증하고 블록체인에 추가합니다.

문제를 가장 먼저 푸는 채굴자에게는 12.

5 비트코인이 보상으로 주어집니다.

작업 증명이라고 하는 이 프로세스는 거래를 완료한 네트워크 내 모든 사용자의 지갑을 업데이트합니다.

더 나은 서비스를 위한 월마트의 블록체인 활용

월마트는 제품 품질 저하로 인한 높은 반품률과 환불 문제로 어려움을 겪었습니다.

이 회사는 블록체인 기술을 도입하여 각 공급망 단계에서 상품의 품질을 영구적으로 기록했습니다.

이러한 혁신을 통해 월마트는 고객이 손상된 제품을 신고했을 때 문제 영역을 정확하게 식별하고 수정할 수 있었습니다.