I’m feeling a bit anxious about this whole blockchain thing. I’ve heard once you send crypto, there’s no turning back. But why is that? How does blockchain ensure that once I make a transaction, it can’t be reversed or tampered with? Is it really that secure?
Each block seals a transaction; breaking the seal is like un-ringing a bell.
Building on the previous points, each transaction on the blockchain is verified by multiple nodes in the network, making it a collective agreement. This verification process involves solving complex cryptographic puzzles, which secures the transaction. Once a transaction is recorded, it’s linked to the previous transaction, creating a chain that’s tamper-evident. To change any information, you’d need to alter all subsequent records, which is computationally impractical. This immutability is what makes blockchain reliable and secure, ensuring that once a transaction is made, it stays made.
This chaining of blocks is secured by hash functions, which produce a unique digital fingerprint for each block. Altering any information within a block would change its hash, making it evident that tampering has occurred. To successfully modify a transaction, an attacker would need to alter not just the target block, but also every subsequent block in the chain, which would require an immense amount of computational power due to the Proof of Work or similar consensus mechanisms employed.
Moreover, the decentralized nature of blockchain means that no single entity has control over the entire ledger, making collusion incredibly difficult. The combination of these cryptographic techniques and decentralized verification processes ensures that once a transaction is added to the blockchain, it becomes irreversible and tamper-evident, thereby providing a high level of security and trust in the system.
To add to the above, blockchain uses a decentralized network of computers to validate transactions. Once they’re added to the ledger, it’s nearly impossible to alter them without consensus, which is hard to achieve. That’s why it’s irreversible.