Blockchain (2) — Blockchain Structure

In today’s world of increasingly frequent international trade, cross-border payments have become a crucial link in the smooth flow of the global economy.

In yesterday’s article, we discussed the application of blockchain in cross-border payments. Today, we will focus on a deeper analysis of the components of blockchain, using practical cases.

At its core, blockchain is a Distributed Ledger Technology (DLT) that creates a new value transfer system through cryptography, consensus mechanisms, and decentralized networks.

The structure of a block includes the block header (hash, timestamp, etc.), transaction data, and the Nonce value. These three components form the “trust triple lock” in cross-border payments.

Imagine blockchain as a digital armored money transport vehicle:

➡️ The block header = the bulletproof control cabin of the vehicle (navigation system + black box + armor); ➡️ Transaction data = the cash boxes stored in the cargo hold; ➡️ The Nonce value = the quantum lock code that is changed before each trip.

When this vehicle crosses national borders (cross-border payments), the triple protection ensures the secure transfer of trillions of dollars in value.

Another example is viewing blockchain as an intelligent container transport system for cross-border trade. The block header acts as the anti-counterfeit seal of the container, the transaction data is the electronic manifest inside the container, and the Nonce value represents the password-breaking competition for unlocking the container lock.

Block header: the blockchain’s “digital ID”

The block header consists of five parts: parent block hash, Merkle root, timestamp, difficulty target, and Nonce.

These five parts are analyzed separately below.

Parent Block Hash: The DNA Chain of Blockchain

In traditional ledger accounting, the page number of the old ledger is manually copied into the first line of the new ledger page. In contrast, blockchain automatically records the GPS coordinates of the previous vehicle in the armored vehicle control cabin’s navigation system.

➡️ The essence of the technology is the SHA-256 encrypted fingerprint of the previous block header.

When a Chinese supplier initiates a payment of €200,000 to a German buyer: Block N-1 Hash: a3d9… (records the exchange of RMB to EUR), Block N Hash contains: parent_hash = sha256(“a3d9… + new transaction”).

This forms an unbreakable payment chain, ensuring that the flow of funds is traceable.

Merkle Root: The “Fingerprint Compressor” of Transaction Data

➡️ Technical principle: All transactions are hashed pairwise in a binary tree, ultimately generating a unique 32-byte digest. ➡️ Real-world mapping: The cross-border payment platform compresses 100,000 transactions into a sealed code, similar to a logistics company generating a unique tracking number, such as SFD2025DE, for an entire shipment. ➡️ Validation advantage: The German buyer does not need to download all the data, only verifying whether their transaction is in the tree (Merkle proof), reducing verification time from 10 minutes to 0.3 seconds.

Timestamp: The Atomic Clock of Global Payments

➡️ Key technology: UTC timestamps accurate to the millisecond, embedded in the block header. ➡️ Cross-border value: Resolves time zone disputes. For example, when a payment is made from Beijing at 9:00 AM to New York at 8:00 PM (previous day), the timestamp anchors the evidence, proving that “payment was made before the contract deadline” in the US-China trade dispute.

Difficulty Target: Blockchain’s “Automatic Speed Regulator”

➡️ Operational mechanism: The entire network dynamically adjusts the difficulty of the hash puzzle based on block production speed (e.g., requiring the first 20 digits to be 0). ➡️ Economic significance: After Ethereum’s London upgrade in August 2025, the difficulty bomb stabilized the block time at 12 seconds, ensuring predictable cross-border payment settlements.

Back to the Container Example: The Corresponding Analogy for the Five Modules：

Case Study: 2024 Cross-Border Payment on a Public Blockchain

🔑 The block header contains the hash of the previous block (e.g., 0x3a7b…), forming a chain of fund traceability. 🔑 The timestamp marks the exact time of the payment from Shanghai to New York (13:45:23.214 UTC). 🔑 The 2,189 transactions are compressed into a 64-bit Merkle root (similar to the DNA fingerprint of the container’s contents).

Transaction Data: The Blood Circulation System of Value Flow

The transaction structure is meticulously designed, with each cross-border payment transaction containing multiple layers of data packets.

01 Input List: Source of Funds Verification

Technical Implementation: Points to previous transaction UTXOs (Unspent Transaction Outputs), such as the second output (0.5 BTC) from transaction TX3.

02 Output List: Value Distribution Instructions

Multi-output Design: outputs = [ { “address”: “Indian Supplier”, “value”: 95,000 USD }, { “address”: “Hong Kong Intermediary”, “value”: 5,000 USD } ]

Innovative Application: In 2024, DBS Bank in Singapore uses Conditional Outputs: When the bill of lading’s SHA256 = 3e8a..., payment is released, achieving trade financing automation.

03 Witness Data: Privacy Protection Breakthrough

➡️ SegWit (Segregated Witness) Innovation: Moves signature data out of the main transaction area, increasing block capacity by 60%.

➡️ Zero-Knowledge Proof (ZKP) Application: JPM Coin by JPMorgan in euro cross-border payments:

• Traditional Model: Exposes payer A → payee B €1,000,000.
• ZKP Model: Proves payment compliance and sufficient balance without revealing the amount or counterparty.

Continuing with the container analogy, the transaction data functions as a digital electronic manifest. Here’s the breakdown of the transaction structure:

🔑 Input: Proof of ownership of goods provided by the sender, including the source transaction ID + digital signature (proving the right to use these funds).

🔑 Output: The recipient’s electronic receipt.

Details: Recipient Address + Amount + Execution Condition (e.g., payment upon arrival).

The Merkle Tree serves as the intelligent partition management of the container. Suppose a block holds 4,000 cross-border transactions (equivalent to 4,000 items). If goods #3 are suspected of being swapped, only the H3 → H34 → root hash path needs to be checked (without unpacking the entire cargo).

For cross-border payments, traditional banks would need to scan the entire database to verify 10,000 transactions (10 minutes+), whereas blockchain verification through the Merkle path takes just 3 seconds (time complexity O(log n) ).

Nonce Value: The “Golden Number” of Proof of Work

The essence of Nonce: Cryptographic Dice Rolling

➡️ Mathematical Definition: A random number that satisfies the condition SHA256(Block Header + Nonce) < Target Value.

➡️ Mining Process Analogy: Miners are like agents blindly guessing the code to a safe.

A standard safe has 10²⁶ possible combinations (equivalent to Bitcoin’s difficulty).

When Nonce = 532,689,142,396, the safe opens (valid hash found).

Nonce Economics in Cross-Border Payments

➡️ Energy Consumption Debate and Solution:

All transactions are hashed pairwise through a binary tree, ultimately generating a unique 32-byte digest.

➡️ Hidden Value of Nonce: Preventing Double-Spending Attacks

When a hacker tries to tamper with the China-Russia oil trade:

Original Transaction: Block #789, Nonce = 0x18A3F, Hash = 00000a7d…

Hacker Falsification: Modifying the transaction amount would require finding a new Nonce.

New Challenge: It would take 10¹⁹ attempts to find a Nonce that makes the hash < Target Value.

Result: It is impossible to complete within the 6-second block interval, and the attack fails.

Collaborative Combat in Cross-Border Payments

The workflow of the three components of blockchain is as follows

1️⃣ Chinese Exporter ➡️ + Blockchain initiates payment (transaction data).

2️⃣ Blockchain ➡️ Miner: Broadcast transaction.

3️⃣ Miner ➡️ Miner: Compete to calculate Nonce.

4️⃣ Winning Miner ➡️ + Blockchain finds Nonce and packages the block.

5️⃣ Blockchain ➡️ Block header writes parent hash + timestamp + Merkle root.

6️⃣ Blockchain ➡️ US Importer: Payment notification (3 seconds).

Through blockchain technology, cross-border payment pain points such as opaque fund flows, exchange rate fluctuations, long settlement cycles, and difficult reconciliation are resolved. Details are shown in the diagram below:

Case Study: Hong Kong-Shenzhen Cross-Border Settlement

🔑 10:00 AM: A Hong Kong company initiates a $5 million payment.

🔑 The block header records timestamp: 2025–07–20 10:00:05 HKT.

🔑 Transaction data includes:

• Input: Hong Kong company’s digital signature (from previous transaction a1b2).
• Output: Shenzhen company’s address + $5,000,000.

🔑 The miner uses a custom ASIC chip, attempting 230 trillion guesses per second, finding the Nonce in 153 seconds.

🔑 Generates new block hash: 0x0000000000000a4d3f… (with 13 leading zeros).

🔑 The Shenzhen company receives the funds at 10:03 AM, with the exchange rate locked at the time of initiation.

Modular Blockchain Breakthrough

Layered architecture solves the “impossible triangle”

• Settlement Layer (Core Block Header): Focuses on Nonce verification and hash linkage.
• Execution Layer (Transaction Processing): Parallel processing of multi-currency cross-border payments.
• Data Availability Layer (Storage): Distributed storage of transaction details.

2025 Cross-Border Payment Test Data

Blockchain technology has significantly promoted financial inclusivity:

• Small and Medium Enterprises (SMEs) benefit: According to the International Chamber of Commerce, blockchain trade financing platforms have reduced SME financing approval cycles from 45 days to 7 days, with loan approval rates increasing by 300%.
• Unbanked populations: Filipino workers can use blockchain remittance applications (e.g., SBI Remit) to exchange cash for digital currency at 7-Eleven convenience stores and send it directly to family members’ mobile wallets, with fees less than 1/5th of traditional channels.

Case Study: Global Supplier Settlement for an E-commerce Platform

🔑 Uses Celestia (data layer) + Polygon (execution layer) + Ethereum (settlement layer).

🔑 Simultaneously processes:

• Turkish lira payment (fabric supplier).
• Brazilian real payment (logistics provider).
• Vietnamese dong payment (contract manufacturer).

🔑 Cost reduced from $38 per transaction to $0.07, saving $210 million annually.

Future Frontiers: Quantum Threats and Post-Quantum Blockchain

Based on current technological trends, the next five years will present three major trends.

1️⃣ Impact of Quantum Computing on Blockchain

2️⃣ Post-Quantum Blockchain Solutions

🚀 As quantum computing advances, existing cryptographic algorithms will face threats. Post-Quantum Cryptography (PQC) will become the cornerstone of blockchain security.

National Standardization Cases:

• China: SM9 Algorithm (Identity-Based Cryptography).
• United States: NIST selects CRYSTALS-Dilithium as the post-quantum signature standard.

🚀 Simultaneously, Quantum Defense of Nonce will be upgraded, employing a multi-dimensional Nonce matrix. Attackers will need to crack 9 linked Nonces simultaneously, nullifying the advantage of quantum computers.

Blockchain is like a modern financial clock: The block header is the dial and hands (space-time coordinates), Transaction data is the escapement wheel (precisely transmitting value), Nonce is the mainspring (driving the system).

When a Swiss watchmaker controls errors within 0.01 seconds, blockchain uses cryptography to ensure the transmission of value with nearly zero error.

Satoshi Nakamoto may not have foreseen that the Nonce competition mechanism he designed would become the cornerstone supporting $400 trillion of annual cross-border trade.

As technologies like ZK-Rollups evolve, future transaction validation will resemble an X-ray machine for containers — allowing visibility into the internal structure (verifiable) while preserving the seal (zero-knowledge).

Blockchain, through the three unified components of the block header (order), transaction data (value), and Nonce (randomness), builds the foundation of trust for the digital age.