DARCA: A comprehensive solution to international transfer challenges
Note
This document provides a detailed description of the architecture and mechanisms of DARCA designed to address systemic issues in international payments, which were outlined in detail in the accompanying research.
Table of contents
- Solution architecture: Dual-circuit payment system
- Problem 1 solution: Slow transfers
- Problem 2 solution: High and non-transparent fees
- Problem 3 solution: Unpredictability and hidden FX losses
- Problem 4 solution: Security and reliability
- Problem 5 solution: Legality and official status of operations
- Problem 6 solution: Business implications
- Technical components of the payment system
- Conclusion
Solution architecture: Dual-circuit payment system
DARCA addresses the problem of slow, expensive, and non-transparent transfers not with a single feature, but with a payment system architecture consisting of two complementary circuits. This dual-circuit model makes it possible to combine the advantages of centralized and decentralized systems, providing both instant internal operations and global reach via public blockchains.
Overall concept
The system is divided into two logical circuits, each optimized for its own set of tasks.
| Circuit | Purpose | Speed | Fees | Currency |
|---|---|---|---|---|
| Circuit A (Instant Internal) | Transfers within the DARCA network | Seconds | 0 | Any supported |
| Circuit B (Stablecoin/Fiat Rails) | External transfers anywhere in the world | Minutes (crypto) or days (fiat) | Low (network-dependent) | Stablecoins or Fiat |
Circuit Ais a high-performance centralized ledger where transfers between DARCA users are executed as atomic records. This enables near-instant execution and zero fees, as the operation does not leave the system boundaries.
Circuit Bis designed for interaction with the outside world. It gives the user a choice: make a traditional but slower fiat transfer, or use stablecoins as a universal transport layer for fast and low-cost global settlements. When choosing the crypto route, the user determines which blockchain network to use, while DARCA provides recommendations on the speed, cost, and reliability of each option.
Problem 1 solution: Slow transfers
Info
As shown by the research, the slowness of traditional transfers is one of the main pain points. DARCA addresses this issue on two levels: through instant internal transactions and high-speed external transfers via blockchain networks.
Internal transfers: Instant execution
An internal transfer within the DARCA system is not an interbank operation, but an atomic posting in its own ledger. When one DARCA user sends funds to another, the system simply updates their balances in its database. This process takes milliseconds and does not depend on bank operating windows. As a result, a transfer that could take several days in a traditional system is executed in DARCA almost instantly, 24/7.
External transfers: User-controlled speed
For external transfers, DARCA offers flexibility. The user can choose:
- Traditional fiat transfer: This route uses standard banking rails. It is slower, but may be preferable for certain counterparties or jurisdictions.
- Stablecoin-based transfer: This route uses cryptocurrencies (for example, USDC) as a transport layer. The user selects the blockchain network (for example, Arbitrum, Solana, Base), and DARCA provides recommendations on the speed-to-cost tradeoff for each option.
| Channel | Time | Availability |
|---|---|---|
| DARCA (internal) | Seconds | 24/7 |
| DARCA (USDC, Arbitrum) | Seconds/minutes | 24/7 |
| SWIFT | 2-5 days | Business days |
| SEPA | 1-4 days | Business days |
By using modern L2 networks, fund delivery can take seconds rather than days. This allows waiting times to be reduced by orders of magnitude compared to traditional banking rails.
Problem 2 solution: High and non-transparent fees
Info
The research showed that hidden FX markups and non-transparent charges are the primary drivers of high costs in international transfers. DARCA addresses this problem by offering a transparent pricing model and efficient routing for payments.
Internal transfers: Zero fees
All transfers within the DARCA network, both fiat and crypto, are executed with zero fees. This is possible because transactions are processed within our own ledger and do not require external intermediaries.
External transfers: Fee minimization through routing
DARCA provides users with tools to significantly reduce fees on external transfers. We do this by offering choice and full support for each option:
- Fiat transfers: We enable transfers via traditional banking networks. While this method is slower and more expensive, it remains an important option for working with counterparties that are not ready to accept cryptocurrency.
- Cryptocurrency transfers: DARCA makes the use of cryptocurrencies for international settlements simple, familiar, and most importantly, legal. The user can choose a fast and low-cost blockchain network, and we provide all the necessary infrastructure to legitimize these operations:
- Tax reports: Automatic generation of reports for tax authorities.
- Legal support: Provision of information and assistance on compliance matters.
- Document generation: Creation of invoices, acts, and other supporting documents.
- Accounting integration: Seamless data synchronization with popular accounting systems.
This approach makes it possible to reduce the cost of an international transfer by orders of magnitude compared to banks. Instead of hidden markups, the user sees all fees before sending the payment.
Problem 3 solution: Unpredictability and hidden FX losses
The issue of unpredictability and hidden losses in currency exchange is addressed in DARCA by locking in all transaction parameters before confirmation and using a transparent market rate. This gives users full control and confidence in the outcome.
Parameter locking before confirmation
Before executing a transfer, the user sees all key parameters on the screen: the sending amount, the exact amount to be received, the exchange rate, all fees, and the estimated execution time. These parameters are locked at the moment of confirmation and do not change during execution. The recipient receives exactly the amount shown on the screen, without any deductions or changes due to rate fluctuations or hidden fees charged by intermediary banks.
Addressing hidden FX losses
DARCA eliminates hidden markups by using a transparent mid-market rate (mid-market rate). Any markup, if applicable, is minimal and always displayed separately, rather than being embedded in the rate. To ensure favorable and predictable currency exchange, the system operates an FX Engine that pulls real-time quotes from liquidity providers and locks the best rate for a short period sufficient for user confirmation.
| Bank transfer | DARCA transfer | |
|---|---|---|
| Transfer amount | €10,000 | €10,000 |
| Hidden FX markup | 3% | 0.3% (transparent) |
| FX loss | €300 | €30 |
| Savings | - | €270 (90%) |
As a result, DARCA not only makes the currency exchange process fully transparent, but also allows users to save up to 90% on hidden fees.
Problem 4 solution: Security and reliability
Security is a core priority for DARCA. The platform uses a multi-layered protection system that ensures the safety of user funds and data without creating unnecessary friction. The system is designed to counter a wide range of threats, from account compromise to fraud and internal abuse.
Access control and confirmations
Account access and transaction execution are protected by modern authentication methods. The platform supports device binding, two-factor authentication (2FA), biometrics, and passkeys. For higher-risk operations (for example, a large transfer to a new address), the system automatically requests a step-up confirmation - an additional authentication factor. Users can also configure recipient whitelists and receive instant notifications about all critical account events.
Risk Engine: Real-time scoring
Every payment is processed through the Risk Engine before execution - a real-time risk analysis system. It evaluates dozens of parameters: device novelty, geolocation, behavioral patterns, transaction history, payment amount, and frequency. Based on this analysis, the system makes a decision: allow the transaction (allow), request additional verification (step-up), pause for manual review (hold), or reject it (deny). This approach makes it possible to instantly stop suspicious transactions without disrupting legitimate operations.
Protocol-level and architectural protections
Warning
System reliability is ensured at the protocol and architecture levels. The use of an Idempotency Key protects against accidental duplicate charges caused by network failures. The Nonce + TTL mechanism (a unique number and request lifetime) prevents replay attacks. All requests are cryptographically signed, eliminating the risk of tampering. The internal ledger is built on the principles of double-entry bookkeeping, ensuring system balance, and ACID atomicity, preventing partial execution of operations. The full transaction history is recorded in an immutable (append-only) log, protected against manipulation using hash chains.
Enterprise-grade security
For business clients, DARCA provides advanced control tools. A role-based access control model (RBAC) allows flexible permission management for different employees. The four-eyes principle (dual approval) can be enabled for large payments. Spending limits can be set for different departments, and payments can be restricted to addresses from a list of verified counterparties. These features help companies prevent both accidental errors and intentional fraud.
Problem 5 solution: Legality and official status of operations
DARCA provides users with all the necessary tools to conduct lawful financial activities and comply with tax regulations. The platform is not a tool for circumventing the law. On the contrary, it helps make operations with digital assets and international settlements as transparent and understandable as possible for regulators.
Transaction dossier (case file for each payment)
Every operation in the system, whether a transfer, exchange, deposit, or withdrawal, is accompanied by the creation of a detailed dossier. It records all key parameters: operation type and amount, assets, fees, counterparty, exchange rate, timestamps, and network identifiers (for external transactions). This dossier serves as official confirmation of the operation and can be used for accounting, tax reporting, and audits.
Reporting for individuals and legal entities
Based on this data, the platform enables the generation of comprehensive reports. Individuals can obtain statements for all their operations for any period at any time, broken down by assets, as well as a detailed history of FX operations for tax calculations. For businesses, the platform provides payment ledgers, FX position reports, reconciliation tools, and, critically, the ability to export data to popular ERP and accounting systems (SAP, 1C, QuickBooks, and others). This automates accounting and significantly reduces the workload on finance teams.
Compliance and regulatory adherence
DARCA operates in strict accordance with the laws of the jurisdictions where it provides services. This includes mandatory customer identity verification (KYC), transaction monitoring for suspicious activity (AML), and blocking operations that violate sanctions regimes. The platform features a flexible configuration system that applies different rules and limits depending on the country, client type, and transfer direction. Users are always informed in advance about applicable limits and requirements.
As a result, DARCA delivers not only technological convenience but also the legal correctness of all operations, which is a necessary condition for trust and mass adoption.
Problem 6 solution: Business implications
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Issues with international payments hit small and medium-sized businesses (SMBs) particularly hard, undermining their financial stability and competitiveness. DARCA offers a comprehensive solution that helps SMBs not only survive but also grow in a global economy.
Solving cash flow gaps
A cash flow gap, which arises when customers pay late while suppliers must be paid on time, is the cause of one in four bankruptcies in Europe. DARCA addresses this issue by reducing the time it takes for funds to be received from several days to a few seconds. If both the customer and the supplier are within the DARCA network, payment is instant. If the supplier is outside the network, a stablecoin-based payment takes minutes. This enables businesses to build a “same-day payment” model and virtually eliminate cash flow gaps, freeing up working capital and reducing the need for expensive borrowing.
Reducing operating costs and FX risks
Beyond direct losses from fees, businesses incur significant indirect costs: employee time spent tracking payments, collecting receivables, and managing FX risks. DARCA automates many of these processes. The platform enables scheduled automatic payments, real-time tracking of all transaction statuses, and instant currency exchange at a transparent rate. This not only saves time but also minimizes FX risks, since the rate is locked at the moment the transaction is executed, not days later.
Improving financial stability and access to credit
By using DARCA, companies improve their payment discipline and financial metrics. Timely payment of supplier invoices strengthens business reputation. The absence of cash flow gaps and a transparent financial history make a company more attractive to banks and investors. As shown by the research, 61% of companies in the EU face deteriorating lending conditions due to payment issues. DARCA helps resolve this by increasing financial stability and, as a result, improving access to the capital required for growth.
| SMB problem | DARCA solution |
|---|---|
| Cash flow gaps | Instant payments that eliminate delays in fund receipt |
| High costs | Savings of up to 95% on fees and hidden spreads |
| FX risks | Instant exchange at a transparent, locked rate |
| Operational burden | Payment automation, tracking, and reporting |
| Access to credit | Improved payment discipline and financial reputation |
Ultimately, adopting DARCA enables small and medium-sized businesses to save tens of billions of dollars annually that were previously lost to inefficient payments. These funds can be reinvested in growth, job creation, and increased competitiveness in the global market.
Technical components of the payment system
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Alias Directory (Alias directory): This service converts human-friendly identifiers (phone number, email, username) into an internal wallet identifier, allowing funds to be sent to a “person” rather than to a complex set of payment details.
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Payment Switch (Payment router): The brain of the system that analyzes each payment and determines the optimal execution route: via the internal ledger (Circuit A) or via an external blockchain (Circuit B).
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Risk Engine (Risk analysis system): Ensures security by analyzing each transaction in real time for fraud and deciding whether to allow it, block it, or require additional verification.
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Ledger Service (Ledger service): The heart of Circuit A. This is a high-performance, multi-currency ledger built on double-entry principles, ensuring atomicity and immutability of all internal operations.
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FX Engine & Treasury (FX engine and Treasury): Responsible for instant and transparent currency exchange at market rates, and for managing the platform’s overall liquidity to ensure uninterrupted execution of all operations.
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Execution Engine (Execution engine): A Circuit B component responsible for interacting with external blockchain networks: it creates, signs, and submits transactions, and tracks their confirmations.
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Notification Service (Notification service): Notifies users of all important events via push notifications, SMS, or email, ensuring transparency and control.
Strategic advantage
Note
The DARCA platform offers a comprehensive and architecturally sound solution to the systemic problems of international payments. Instead of patching gaps in outdated financial infrastructure, DARCA creates a new, more efficient model based on a dual-circuit architecture.
| Parameter | Traditional channels (Banks/SWIFT) | DARCA solution |
|---|---|---|
| Speed | Hours and days | Seconds and minutes |
| Cost | High and non-transparent (up to 12%) | Low and transparent (0-0.5%) |
| Predictability | Low | Absolute (parameter locking) |
| Availability | Limited to business hours | 24/7/365 |
| Business impact | Cash flow gaps, high costs | Financial stability, savings |
The DARCA solution makes international financial operations what they should be in the 21st century: fast, affordable, transparent, and secure. This delivers direct benefits to end users and businesses by saving time and money, and also supports global economic development by removing barriers to international trade and financial flows.