Blockchain Explained: Everything You Need to Know

Estimated reading time: 3 minutes

• What Is Blockchain?
• The Problem with Traditional Transactions
• Enter Blockchain
• How Blockchain Works
• Cryptography in Blockchain
• Mining and Proof of Work
• Real-Life Applications of Blockchain
• Conclusion

Ever wondered if there’s an easier way to complete transactions without involving online wallets, banks, or third-party applications? Thanks to blockchain technology, this is now possible. Here’s an in-depth look at how blockchain works and its applications.

What Is Blockchain?

Blockchain is a revolutionary technology that powers cryptocurrencies and eliminates the need for a central authority. It is a secure, decentralized digital ledger that records transactions in a way that is transparent, permanent, and tamper-proof.

The Problem with Traditional Transactions

Consider a scenario where four friends—Jack, Ted, Sam, and Phil—dine together, and Jack pays the bill. The next day, the friends reimburse Jack via online money transfer. While Phil’s transaction succeeds, Ted and Sam’s fail due to issues such as technical errors, daily transfer limits, or additional transfer charges. These challenges highlight the limitations of traditional banking systems.

Enter Blockchain

To overcome these issues, cryptocurrencies were introduced. Cryptocurrencies are digital or virtual currencies that operate on blockchain technology. They are immune to counterfeiting, do not require central authorities, and are secured by complex encryption algorithms.

Among thousands of cryptocurrencies, Bitcoin is the most prominent. Blockchain records every transaction in a distributed ledger, ensuring transparency and security.

How Blockchain Works

Let’s revisit the friends’ example, this time using Bitcoin:

1. Recording Transactions:
   • Phil sends 2 bitcoins to Jack. This transaction is recorded as a “block.”
   • The block also updates the balance: Phil now has 1 bitcoin, and Jack has 7.
2. Adding Blocks:
   • When Ted and Sam send their shares, separate blocks are created for each transaction. These blocks record the updated balances and are linked to the previous blocks, forming a chain.
3. Validating Transactions:
   • If Phil tries to send 2 bitcoins when he only has 1, the transaction is flagged as invalid because the distributed ledger is accessible to all participants.

This chain of records is what we call the blockchain. Its distributed nature ensures that no single user can alter the data, making it highly secure.

Cryptography in Blockchain

Each blockchain participant has:

• A Public Key: An address visible to everyone (like an email address).
• A Private Key: A secret key known only to the user (like a password).

When Phil initiates a transaction, he uses his private key to digitally sign it. The transaction is encrypted and sent to Jack’s public key, ensuring that only Jack can decrypt it using his private key.

Bitcoin uses the SHA-256 algorithm for encryption, while other cryptocurrencies like Ethereum use different algorithms such as Ethash.

Mining and Proof of Work

Transactions are validated by individuals known as miners who solve complex mathematical problems. The process of solving these problems is called Proof of Work, and the addition of validated blocks to the blockchain is known as mining. Miners are rewarded with Bitcoin for their efforts.

Real-Life Applications of Blockchain

Blockchain isn’t just for cryptocurrencies. For instance, Walmart uses blockchain to enhance its supply chain management. By recording the quality of goods at every stage—from farm to storage to delivery—Walmart can identify and rectify issues effectively, reducing returns and refunds.

Conclusion

Blockchain is a transformative technology that ensures secure, transparent, and tamper-proof transactions. It has applications in various fields, from finance to supply chain management.

Quiz: What ensures data cannot be altered within a blockchain network?
A. Public Distributed Ledger
B. Proof of Work
C. Proof of Stake
D. Hash Encryption

Let us know your answers in the comments below.