Blockchain technology has revolutionized the way data is stored and shared across decentralized networks. At the core of this innovation lies a specific model that defines how information is written to the blockchain in a secure and transparent manner.

Understanding this model is crucial for grasping the fundamental principles that enable blockchains to maintain data integrity, immutability, and trustless consensus among participants. In this article, we’ll explore the intricate details of the model that underpins data recording on blockchains.

Which Model Describes How Data Is Written in Blockchain?

Virtually anything of value can be included in data, which can be both tangible and intangible. Blockchain’s distributed architecture lowers costs and risks for those involved.

The append-only model is a core principle in blockchain technology that dictates how data is written and stored. Once information is added to a blockchain, it cannot be changed or deleted. This generates an immutable log of every transaction.

Imagine a historical ledger where every entry is permanently engraved. That’s the essence of immutability in blockchains. A brilliant blend of distributed ledger technology and cryptography makes data written to a blockchain nearly unalterable.

How Does It Achieve Immutability?

The append-only model fosters trust, as once a transaction is validated and recorded it becomes a permanent part of history, resistant to manipulation and deletion. This immutability is the basis of blockchain’s security and transparency, making it ideal for applications where trust is paramount. The append-only model achieves immutability on blockchains through a three-pronged approach — cryptography, chained blocks, and distributed ledgers.

1. Cryptographic Hashing

Imagine a document with a unique fingerprint. Any change to the document would alter the fingerprint, raising red flags. Blockchains employ a similar concept called hashing.

• Every piece of data written to the blockchain undergoes a cryptographic hashing function. This function scrambles the data into a seemingly random string of characters called a hash. The key point is, any alteration to the data, however minor, drastically changes the hash.

• When a transaction is added to a block, its data is hashed. This hash becomes a permanent part of the block’s record. If someone tries to tamper with the data later, the hash will no longer match the original data, exposing the attempted manipulation.

2. Chained Blocks

• Transactions aren’t stored in isolation on a blockchain. They are grouped into chronological “blocks.” Each block not only contains transactions but also references the unique hash of the previous block. This creates a chain of blocks, where each block acts like a link that depends on the integrity of the previous link.

• To tamper with a past transaction, an attacker wouldn’t just need to modify the targeted block; they would need to alter every subsequent block in the chain. This is because each subsequent block references the hash of the previous block. Changing a past transaction’s data would invalidate its hash, leading to a mismatch with the reference hash in the following block.

• Recalculating the hashes of all subsequent blocks to hide the tampering would require immense computing power, making it practically infeasible on most blockchains.

3. Distributed Ledgers

• Unlike traditional storage systems where data resides on a single server, blockchains are inherently distributed. Every computer participating in the network (called a node) holds a complete copy of the blockchain ledger.

• This means that tampering with data on a single node wouldn’t affect the data on other nodes. An attacker would need to manipulate every copy of the blockchain across the entire network to successfully alter data. This is nearly impossible to achieve on a large and well-established blockchain network.

Benefits of the Append-Only Model

The append-only model offers several key benefits that make it a powerful tool for blockchain technology. Here are the main advantages:

1. Enhanced Transparency and Auditability

• Immutable Record

Since data cannot be changed or deleted, the append-only model creates an unalterable record of every transaction on the blockchain. This complete and transparent history fosters trust within the network as everyone can see every action that has taken place.

• Improved Accountability 

With all transactions permanently recorded, participants are held accountable for their actions. This transparency discourages fraudulent activities and promotes responsible behavior on the network.

2. Increased Security and Data Integrity

• Cryptographic Safeguards

The use of hashing functions ensures that any attempt to tamper with data will be immediately detected. The unique hash acts like a digital fingerprint, exposing any modifications.

• Resistance to Manipulation

The chained block structure makes altering past data incredibly difficult. Modifying a single transaction would require changing all subsequent blocks on the entire network, a near-impossible feat due to the distributed nature of the ledger.

• Distributed Redundancy

By having every node hold a copy of the blockchain, the append-only model eliminates single points of failure. Even if one node is compromised, the remaining nodes maintain a valid copy of the data, ensuring its integrity.

3. Empowering Users and Decentralization

• Reduced Reliance on Central Authorities

The append-only model removes the need for centralized authorities to control and manage data. Users have greater control over their information and transactions, fostering trust in a decentralized environment.

• Increased Confidence

Knowing that data is immutable and tamper-proof allows users to be confident that their information remains secure and unaltered.

4. Additional Advantages

• Improved Traceability

The append-only model facilitates efficient tracking of assets and data throughout their lifecycle. This transparency is valuable in supply chain management and other applications where audit trails are crucial.

• Enhanced Efficiency

By eliminating the need for reconciliation and dispute resolution processes associated with potentially altered data, the append-only model can improve overall efficiency within a system.

Smart Contracts

Another aspect of writing data to a blockchain are smart contracts. These are digital contracts that are automatically executed upon the fulfillment of predefined terms and conditions and are maintained on blockchains. On a blockchain, smart contracts are composed of straightforward statements that are written into code. 

After a set of predefined conditions are validated, a network of computers execute these transactions. Every action that has been completed is updated on the blockchain, which makes it transparent and irreversible. When a new blockchain is formed, the information kept in a block is taken from transactions recorded in earlier blocks, thus preventing tampering throughout the entire system.