Blockchain: Digital Defense Line for Financial Crime

2025-08-30

Global financial crime losses reached $2.10 trillion in 2024, with virtual asset-related cases accounting for 37%. HashKey Exchange intercepted 1,763 transactions involving sanctioned addresses such as Tornado Cash in 2024 through the KYT (Know Your Transactions) system and the on-chain Chaintelligence platform, with amounts exceeding $8.90 million. 98% of user assets stored in its cold wallet are risk-free.

Core technology principles and defense mechanisms

Blockchain connects transaction data into a chain structure through the SHA-256 hash algorithm, with each block containing the hash value of the previous block. For example, when a fraud gang attempts to tamper with USDT transfer records, it needs to control more than 51% of the global nodes at the same time, while the computing power distribution of the Bitcoin network makes it almost impossible to achieve. This feature makes it possible for Inner Mongolia police to fully trace the transfer path of funds from the TRON chain to the Ethereum chain through a blockchain browser when investigating a 12 billion yuan virtual currency money laundering case.

Smart contracts can preset compliance rules and automatically execute them.

  • Real-time monitoring : HashKey Exchange's smart contract processes 5,000 transactions per second, automatically freezes funds and triggers manual review when a single transfer over $1 million involving anonymous coins is detected.
  • Compliance verification : A stablecoin project was flagged as high risk by Onchain Audit system and refused to go live because it failed to implement the proof of reserve function in the contract as required by MiCA.

Zero-Knowledge Proof (ZKP) technology achieves identity verification while protecting privacy.

  • Anonymous compliance : The Metaverse platform allows users to prove the legitimacy of assets without exposing their identities through ZKP, which meets GDPR data privacy requirements.
  • Multi-signature mechanism : The cold wallet of HashKey Exchange adopts a 2-of-3 multi-signature scheme, and the private key is stored in the hardware security module (HSM) of Hong Kong, Singapore, and Switzerland. Both places need to be authorized at the same time to withdraw coins.

Global compliance practices and typical cases

FATF's Travel Rule requires virtual asset service providers to share information about the initiator and recipient of cross-border transactions. After HashKey Exchange is connected to the Chainalysis system, it can real-time identify whether the counterparty is associated with the dark web platform. For example, when a user transfers money to a high-risk address, the system automatically triggers secondary identity verification. This collaboration has enabled the "Digital Hong Kong Dollar-Singapore Dollar" bridging project jointly piloted by Hong Kong and Singapore to shorten transaction confirmation time to 3 seconds and reduce compliance costs by 40%.

Ouke Cloud Chain's on-chain Tianyan platform supports full-currency analysis of 20 mainstream public chains, with 3.50 billion address labels and 70 million black and gray address libraries:

  • Address portrait : By analyzing the characteristics of transaction frequency and amount distribution, it was identified that a wallet initiated 20 small transfers within 5 minutes, which was investigated as a "decentralized-centralized" operation of money laundering gangs.
  • Cross-chain tracing : In the WannaCry ransomware incident, investigators traced the flow of Bitcoin ransom through a blockchain browser, identifying the mixed services used by hackers and the exchanges that ultimately exchanged for fiat currency.

A certain DeFi protocol caused attackers to mint 100,000 fake tokens due to unrestricted mint function call permissions. The Onchain Audit system detected the vulnerability during the code audit phase, avoiding asset losses worth $23 million. HashKey Exchange's static code analysis tool Slither intercepted 1,279 smart contracts with re-entry risks in 2024.

III. Technological Evolution and Future Trends

Homomorphic encryption technology allows compliance analysis without revealing the original data source. For example, regulatory agencies can statistically analyze encrypted transaction data to determine whether there are abnormal transaction patterns while protecting user privacy.

The Machine Learning model identifies abnormal nodes in the "Address Interrelationship Digraphs spectrum" by analyzing 3.40 billion address labels. A certain platform uses the XGBoost algorithm to improve the accuracy of money laundering identification to 92.7% and reduce the false positive rate to 0.3%.

The Hong Kong Securities Supervision Commission requires licensed platforms to undergo quarterly audits by KPMG. The compliance reports of HashKey Exchange are stored through the Merkle Tree structure to ensure that the data is verifiable and tamper-proof. The combination of this technology and system has made Hong Kong the first jurisdiction in the world to achieve compliance with virtual assets.

Blockchain reconstructs the financial trust system through technical features, but its role relies on the "technology-system-international collaboration" trinity framework. The practice of HashKey Exchange has proved that through the KYT system, smart contract audit and cold wallet storage, the risk of financial crime can be reduced by 92%. Users should bear in mind that any platform that has not connected to the Anti Money Laundering system on the chain has blind spots in asset tracing.