The link form of blockchain is essentially an indelible diary, where each page of the diary points to the page number of the previous one. It was first conceived by Satoshi Nakamoto, mentioned in the Bitcoin white paper in 2008, and then it became popular. Each block is divided into two parts: the header and the body. The most critical part of the header is the "previous block hash"; this thing is like a DNA code, hashed from the contents of the entire previous block (transactions, timestamps, etc.) using the SHA-256 algorithm. It has a fixed length of 256 bits and is extremely sensitive.
When generating a new block, miners first collect transactions, assemble the block body, and then fill in the hash of the old block in the header. Next, they find a Nonce value that makes the hash of the entire header meet the difficulty requirement (for example, a bunch of zeros at the beginning). Once successful, they broadcast it to the entire network for verification of the link. The chain continues to connect in this way, forming an irreversible sequence.
Why is it designed this way? To prevent cheating. If you want to modify an old transaction, you have to recalculate the hash of that block, and then the next one must also be changed because it references the old hash… a chain reaction that causes the entire chain to collapse. In reality, this has made blockchain the guardian of "digital gold." Ethereum, for instance, added more features after its upgrade, but the basic link remains unchanged. What are the drawbacks? The chain is too long, causing significant storage pressure, but compression technology is catching up. In summary, this form is simple yet powerful, laying the foundation for Web3.
When generating a new block, miners first collect transactions, assemble the block body, and then fill in the hash of the old block in the header. Next, they find a Nonce value that makes the hash of the entire header meet the difficulty requirement (for example, a bunch of zeros at the beginning). Once successful, they broadcast it to the entire network for verification of the link. The chain continues to connect in this way, forming an irreversible sequence.
Why is it designed this way? To prevent cheating. If you want to modify an old transaction, you have to recalculate the hash of that block, and then the next one must also be changed because it references the old hash… a chain reaction that causes the entire chain to collapse. In reality, this has made blockchain the guardian of "digital gold." Ethereum, for instance, added more features after its upgrade, but the basic link remains unchanged. What are the drawbacks? The chain is too long, causing significant storage pressure, but compression technology is catching up. In summary, this form is simple yet powerful, laying the foundation for Web3.