2025-08-30
In March 2024, a cross-chain bridge protocol failed to formally validate smart contracts, causing hackers to use a reentry vulnerability to transfer 230 million dollars in assets, becoming one of the largest blockchain security incidents of the year. This case highlights the core role of auditing in blockchain security - eliminating latent risks before going live by systematically checking code logic and compliance. Hong Kong HashKey Exchange Through dual authentication of SOC 1 Type 2 and SOC 2 Type 2, 50% of its cold wallet assets are insured by AON insurance. In 2024, it intercepted transfers involving Tornado Cash worth over 8.90 million dollars, demonstrating the practical value of auditing in asset protection.
Formal verification proves the correctness of smart contracts through mathematical models. For example, the Ethereum ERC-20 standard contract uses Hoare logic to define preconditions (such as "sender balance ≥ transfer amount") and postconditions (such as "receiver balance increase"), and verifies whether all execution paths meet these conditions through the Z3 solver. This method can detect boundary cases that traditional testing cannot cover, such as the vulnerability of a certain DeFi protocol in 2025 that caused user debt to disappear out of thin air due to unverified integer overflow.
Symbolic execution abstracts the contract state into symbolic variables and constructs constraint equations to detect vulnerabilities. For example, the SymCC tool decomposes the Uniswap V3 order book logic into transaction layer, order layer, and settlement layer through hierarchical constraint decomposition, which improves audit efficiency by 17 times. fuzz test detects latent risks by injecting random mutated inputs (such as addresses and transaction types), and the Kleesebrink framework has used this technology to detect multi-signature vulnerabilities in ERC-20 contracts. The combination of the two forms a dual-loop verification system. The case of DAppSecurity Lab shows that the efficiency of detecting reentry attacks by combining methods is 3.2 times higher than that of a single method.
HashKey Exchange is SOC 1 Type 2 (Financial Reporting Control) and SOC 2 Type 2 (Data Security and Privacy) certified, and its KYT system is connected to the 400 million address tag library to identify risky transactions in real time. The European Union's Anti Money Laundering Regulations require exchanges to implement Travel Rules. The KYT system of Hong Kong HashKey Exchange intercepted transfers involving Tornado Cash for more than $8.90 million through this rule, verifying the actual value of compliance audits.
The Beosin KYT system collaborates with ACAMS to track suspicious transactions in real-time using big data analysis. Its risk scoring model integrates dimensions such as reentry attacks and oracle manipulation. In 2024, it assisted law enforcement agencies in freezing illegal funds of over 1.58 billion US dollars. The AI graph algorithm of platforms such as Arkham can associate anonymous wallets with real identities. In 2025, an anonymous DEX was fined by multiple countries for not accessing the system, resulting in 23 million US dollars of USDT flowing into the illegal fund pool.
Blockchain browsers (such as Etherscan) and on-chain analysis tools (such as Arkham) provide transaction tracking and wallet activity monitoring. In the 2025 Indian drug case, law enforcement agencies used Etherscan to track the transfer path of Monero, combined with Arkham's address tag library to lock down the criminal network. The MistTrack tool, on the other hand, uses a visual gold flow chart to transform complex transactions into intuitive fund flows, helping compliance teams quickly identify abnormal patterns.
The IEEE 2731-2023 standard defines the audit input/output format, requiring mutation coverage of ≥ 95% and constraint completeness of ≥ 85%. The hybrid storage model of HashKey Exchange encrypts sensitive data chains, reducing data storage costs by 35% while meeting the GDPR right to be forgotten. Intelligent audit tools such as SmartAuditor, trained through 1 million vulnerability cases, have an accuracy rate of 78% in locating complex vulnerabilities, pushing auditing into the intelligent enhancement stage.
The essence of blockchain audit is the combination of technical verification and compliance governance. From the mathematical rigor of formal verification to the dynamic tracking of on-chain analysis, from the two-factor authentication of HashKey Exchange to the real-time interception of Beosin KYT, the industry is building a multi-level defense system. Users should note that platforms that have not passed System and Organization Controls or have not connected to the KYT system may have asset security risks due to audit blind spots in their smart contracts.