Solidity Finance — APAC Compliance Skill

Singapore — MAS Payment Services Act (PSA)

// PSA License types relevant to DeFi/crypto:
// - Major Payment Institution (MPI): unlimited transaction volume
// - Standard Payment Institution (SPI): limited volume
// - Money-Changing Licence: FX only

enum MASLicenceType { NONE, SPI, MPI, EXEMPT }

interface IMASRegistry {
    function getLicence(address entity) external view returns (MASLicenceType);
    function isNoticeApplicable(address entity, uint256 noticeId) external view returns (bool);
    function isSingaporeResident(address investor) external view returns (bool);
}

// MAS Notice PSN01: DPT service providers must implement AML/CFT
// MAS Notice PSN02: Safeguarding customer assets
contract SingaporeDPTService {
    IMASRegistry public masRegistry;

    // MAS safeguarding: customer assets must be held separately
    address public safeguardingAccount; // Separate trust/custodian account
    mapping(address => uint256) public customerBalances;
    uint256 public totalCustomerFunds;

    modifier onlyMASLicensed() {
        require(
            masRegistry.getLicence(address(this)) != MASLicenceType.NONE,
            "PSA: MAS licence required"
        );
        _;
    }

    // MAS Notice PSN02: Safeguarding obligation
    function deposit(uint256 amount) external onlyMASLicensed {
        require(kycRegistry.isVerified(msg.sender), "PSA: KYC required");
        customerBalances[msg.sender] += amount;
        totalCustomerFunds += amount;
        // Funds must be in segregated safeguarding account
        IERC20(stablecoin).safeTransferFrom(msg.sender, safeguardingAccount, amount);
    }

    // Singapore stablecoin framework (MAS PS-S01):
    // Single-currency stablecoins pegged to SGD or G10 currencies
    // Reserve: 100% in cash/cash equivalents or sovereign bonds ≤3mo maturity
}

// MAS retail investor restrictions
uint256 constant MAS_RETAIL_CAP_SGD = 75_000e18; // S$75,000 annual cap for retail DPT purchases

Hong Kong — SFC VASP Licensing

// SFC VASP licence required from June 2023 (AMLO amendment)
// Two-tier system: SFC (securities) + HKMA (stablecoins/payments)

enum SFCLicenceType { NONE, TYPE_1, TYPE_7, VASP }
// Type 1: Dealing in securities (security tokens)
// Type 7: Providing automated trading services
// VASP: Virtual Asset Service Provider (from 2023)

interface ISFCRegistry {
    function getLicence(address entity) external view returns (SFCLicenceType);
    function isApprovedVirtualAsset(bytes32 assetId) external view returns (bool);
    function isProfessionalInvestor(address investor) external view returns (bool); // HK$8M threshold
}

// HK: Retail access to virtual assets allowed (unlike pre-2023 PI-only rule)
// BUT: complex products (derivatives, leveraged) still PI-only
contract HKVirtualAssetPlatform {
    ISFCRegistry public sfcRegistry;

    uint256 constant PI_THRESHOLD_HKD = 8_000_000e18; // HK$8 million = Professional Investor

    modifier onlySFCLicensed() {
        require(
            sfcRegistry.getLicence(address(this)) != SFCLicenceType.NONE,
            "SFC: VASP licence required"
        );
        _;
    }

    modifier onlyApprovedAsset(bytes32 assetId) {
        require(sfcRegistry.isApprovedVirtualAsset(assetId), "SFC: asset not approved for retail");
        _;
    }

    // HK Stablecoin Bill 2024: issuer licence required for HKD-pegged stablecoins
    // Reserve: 100% in HKD or equivalent high-quality liquid assets
    // Redemption: within 1 business day
}

Japan — FSA FIEA + PSA

// Japan classifies crypto into two categories:
// 1. Crypto-assets (暗号資産): BTC, ETH-like → regulated under PSA
// 2. Security tokens (電子記録移転有価証券表示権利等): equity/bond tokens → FIEA

enum JapanAssetType { CRYPTO_ASSET, SECURITY_TOKEN, ELECTRONIC_PAYMENT_INSTRUMENT }

// Japan FSA: Crypto Exchange Service Providers (CESP) must register
// Security Token Offering platforms: Type I Financial Instruments Business registration

contract JapanSecurityToken {
    // FIEA: Security tokens must use approved blockchain (FSA whitelist)
    bytes32 public approvedBlockchain; // e.g., keccak256("ETHEREUM_MAINNET")

    // Japan: strict transfer restrictions for security tokens
    // Cannot transfer to non-residents without additional disclosure
    mapping(address => bool) public isJapanResident;
    mapping(address => bool) public isQualifiedInstitutionalInvestor; // QII

    uint256 constant QII_THRESHOLD_JPY = 1_000_000_000e18; // ¥1 billion

    // FSA: Security token transfers must be reported to CESP/custodian
    event SecurityTokenTransfer(
        address indexed from,
        address indexed to,
        uint256 amount,
        uint256 timestamp,
        bool crossBorder
    );

    function transfer(address to, uint256 amount) public override returns (bool) {
        bool crossBorder = isJapanResident[msg.sender] != isJapanResident[to];
        if (crossBorder) {
            // Cross-border transfers require additional disclosure under FIEA
            require(crossBorderDisclosureRegistry.hasDisclosure(msg.sender, to), 
                    "FIEA: cross-border disclosure required");
        }
        emit SecurityTokenTransfer(msg.sender, to, amount, block.timestamp, crossBorder);
        return super.transfer(to, amount);
    }

    // Japan PSA Amendment 2023: Stablecoins only issuable by:
    // - Banks, fund transfer service providers, trust companies
    // Foreign stablecoin issuers must appoint Japan-based agent
}

South Korea — Virtual Asset User Protection Act (2024)

// VAUPA effective July 2024: investor protection focused
// VASP registration with FSC required (since 2021 under SPTCA)

contract KoreaVASP {
    // VAUPA: mandatory hot/cold wallet separation
    // ≥80% of customer assets in cold storage
    uint256 public coldStoragePercent; // Must be ≥ 80e16 (80%)
    uint256 public constant MIN_COLD_STORAGE = 80e16;

    // VAUPA: mandatory insurance or reserve fund
    uint256 public insuranceFundBalance;
    uint256 public constant MIN_INSURANCE_RATIO = 5e16; // 5% of customer assets

    // VAUPA: market manipulation prohibition
    // Wash trading, spoofing, layering all explicitly prohibited
    mapping(address => uint256) public lastTradeTimestamp;
    mapping(bytes32 => uint256) public orderCount; // Per address per block

    uint256 constant WASH_TRADE_WINDOW = 30 seconds;

    modifier antiWashTrade() {
        require(
            block.timestamp > lastTradeTimestamp[msg.sender] + WASH_TRADE_WINDOW,
            "VAUPA: potential wash trade detected"
        );
        lastTradeTimestamp[msg.sender] = block.timestamp;
        _;
    }

    // VAUPA: abnormal trading must be reported to FSC/FSS
    event AbnormalTradingDetected(address indexed trader, string reason, uint256 timestamp);

    // Korea: real-name verification system — must link to Korean bank account
    mapping(address => bytes32) public realNameVerificationHash; // Hash of verified KRW bank account
}

Australia — ASIC + AUSTRAC

// Australia: crypto may be a "financial product" under Corps Act 2001
// ASIC CP 343 (2023): guidance on when tokens are financial products
// AUSTRAC: AML/CTF registration required for DCEs (Digital Currency Exchanges)

enum AustralianAssetClassification {
    NOT_FINANCIAL_PRODUCT,  // Pure utility token
    MANAGED_INVESTMENT,     // If pooled funds with expectation of return
    DERIVATIVE,             // If price derived from another asset
    NON_CASH_PAYMENT        // Payment token (AUSTRAC regulated)
}

contract AustralianTokenOffering {
    AustralianAssetClassification public classification;
    bytes32 public austracRegistrationNumber;
    bytes32 public asicLicenceNumber; // AFSL if financial product

    // ASIC: retail PDS (Product Disclosure Statement) required for financial products
    bytes32 public pdsIPFSCid;
    uint256 public pdsDate;

    // AUSTRAC: Travel Rule for transfers ≥ A$1,000
    uint256 constant AUSTRAC_TRAVEL_RULE_THRESHOLD = 1_000e18; // A$1,000

    // ASIC CP 343: Hawking prohibition — no unsolicited offers of financial products
    mapping(address => bool) public hasOptedIn;

    modifier noHawking(address recipient) {
        if (classification != AustralianAssetClassification.NOT_FINANCIAL_PRODUCT) {
            require(hasOptedIn[recipient], "ASIC: no unsolicited financial product offers");
        }
        _;
    }

    // Australia: sophisticated/professional investor threshold A$2.5M net assets or A$250k income
    uint256 constant SOPHISTICATED_INVESTOR_ASSETS = 2_500_000e18;  // A$2.5M
    uint256 constant SOPHISTICATED_INVESTOR_INCOME = 250_000e18;    // A$250k
}

Cross-APAC Common Patterns

// Travel Rule thresholds by jurisdiction
mapping(bytes2 => uint256) public travelRuleThresholds;
// SG: SGD 1,500 | HK: HKD 8,000 | JP: JPY 100,000 | KR: KRW 1,000,000 | AU: AUD 1,000

// Sanctions lists vary by jurisdiction — must check all applicable lists
interface IAPACSanctionsOracle {
    function isSanctionedUNSC(address wallet) external view returns (bool);
    function isSanctionedMAS(address wallet) external view returns (bool);   // Singapore
    function isSanctionedOFAC(address wallet) external view returns (bool);  // US SDN (often required)
    function isSanctionedFSA(address wallet) external view returns (bool);   // Japan
    function isSanctionedAustralian(address wallet) external view returns (bool);
}

modifier apacSanctionsCheck(address party, bytes2 jurisdiction) {
    require(!sanctionsOracle.isSanctionedUNSC(party), "APAC: UN sanctions");
    if (jurisdiction == "SG") require(!sanctionsOracle.isSanctionedMAS(party), "MAS: sanctioned");
    if (jurisdiction == "AU") require(!sanctionsOracle.isSanctionedAustralian(party), "AUSTRAC: sanctioned");
    _;
}

Security & Compliance Checklist

• Identify target APAC jurisdiction(s) before writing compliance logic
• Singapore: MAS licence type verified; safeguarding account segregated
• Hong Kong: SFC VASP licence; asset on SFC approved list for retail
• Japan: asset classified (crypto-asset vs security token vs EPI); CESP registered
• South Korea: ≥80% cold storage; insurance fund ≥5%; wash trade prevention active
• Australia: ASIC classification determined; AUSTRAC registered; PDS if financial product
• Travel Rule thresholds respected per jurisdiction
• All applicable sanctions lists checked (UNSC + local)
• Cross-border transfers flag nationality of sender/receiver

Reference Files

• references/mas-psa-details.md — Singapore PSA licensing, DPT notices, stablecoin framework
• references/sfc-hkma-details.md — Hong Kong VASP licensing, SFC circulars, HKMA stablecoin
• references/japan-fiea-psa.md — Japan security token framework, crypto-asset exchange rules