> For the complete documentation index, see [llms.txt](https://docs.dcn.foundation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.dcn.foundation/part-ii-architecture/02-architecture/04-system-architecture/data-flow.md). # Data Flow > *The DCN Data Flow defines how information moves securely between users, Physical Digital Assets, wallets, publishers, merchants, verification services, and blockchain networks. Every interaction follows standardized communication patterns that ensure security, interoperability, and consistency across the ecosystem.* *** ## Introduction The DCN ecosystem is composed of multiple independent participants. Whenever a user taps a Digital Crypto Note, reloads value, transfers ownership, or verifies authenticity, information travels through several architectural components. Unlike traditional payment systems, where most operations occur within a single institution, the DCN ecosystem distributes responsibilities across hardware, software, infrastructure, and blockchain networks. The purpose of the Data Flow model is to standardize these interactions so that every compliant implementation behaves predictably. *** ## Data Flow Objectives The DCN Data Flow is designed to achieve the following objectives: * Secure communication * Minimal trust assumptions * Interoperability * Low latency * Multi-chain compatibility * Offline support where applicable * Standardized messaging * Auditability * Privacy protection *** ## High-Level Data Flow The following diagram illustrates the primary flow of information within the DCN ecosystem. ```mermaid flowchart LR User --> PDA["Physical Digital Asset"] PDA --> Wallet Wallet --> Verification["Verification Service"] Verification --> Publisher Verification --> Blockchain Publisher --> Registry Blockchain --> Wallet Wallet --> Merchant Merchant --> User ``` Every interaction is initiated by a user and completed through a sequence of standardized communication steps. *** ## Communication Layers Data moves through several logical communication layers. ```mermaid flowchart TB UserLayer["User Interaction"] ApplicationLayer["Wallet / Merchant Application"] ProtocolLayer["DCN Protocol"] TransportLayer["NFC / Internet"] InfrastructureLayer["Verification & Publisher"] BlockchainLayer["Blockchain Network"] ``` Each layer is responsible for processing specific types of information while remaining independent of implementation details. *** ## Typical User Interaction A standard interaction begins when the user taps a Physical Digital Asset using a compatible wallet or merchant device. ```mermaid sequenceDiagram participant User participant PDA participant Wallet User->>PDA: Tap Device PDA->>Wallet: Secure NFC Session Wallet->>PDA: Authentication Challenge PDA-->>Wallet: Signed Response Wallet-->>User: Asset Recognized ``` No sensitive cryptographic material leaves the Secure Element during this interaction. *** ## Authentication Flow Before any operation is permitted, the device must prove its authenticity. ```mermaid sequenceDiagram participant Wallet participant PDA participant Verification Wallet->>PDA: Challenge PDA-->>Wallet: Digital Signature Wallet->>Verification: Validate Signature Verification-->>Wallet: Device Trusted ``` Authentication ensures the physical device is genuine before additional operations proceed. *** ## Certificate Validation Flow Certificates establish trust between ecosystem participants. ```mermaid sequenceDiagram participant Wallet participant Verification participant Certification Wallet->>Verification: Request Certificate Validation Verification->>Certification: Verify Trust Chain Certification-->>Verification: Certificate Status Verification-->>Wallet: Trusted / Rejected ``` Certificate validation protects the ecosystem from unauthorized or counterfeit devices. *** ## Ownership Verification Flow Ownership information is verified using blockchain records. ```mermaid sequenceDiagram participant Wallet participant Blockchain Wallet->>Blockchain: Query Asset Ownership Blockchain-->>Wallet: Owner Information Wallet-->>User: Ownership Confirmed ``` The blockchain remains the authoritative source for ownership and transaction history. *** ## Payment Flow A payment transaction involves multiple participants. ```mermaid sequenceDiagram participant Customer participant PDA participant Merchant participant Wallet participant Blockchain Customer->>PDA: Tap PDA->>Wallet: Authenticate Wallet->>Blockchain: Verify Balance Blockchain-->>Wallet: Balance Wallet->>Merchant: Payment Authorization Merchant-->>Customer: Payment Accepted Wallet->>Blockchain: Submit Transaction Blockchain-->>Wallet: Transaction Confirmed ``` Depending on the implementation, settlement may occur immediately or asynchronously. *** ## Asset Issuance Flow When a Publisher issues a new Physical Digital Asset, multiple systems cooperate. ```mermaid flowchart LR Publisher Publisher --> Manufacturing Manufacturing --> SecureProvisioning["Secure Provisioning"] SecureProvisioning --> DeviceIdentity DeviceIdentity --> Certificates Certificates --> BlockchainRegistration["Blockchain Registration"] BlockchainRegistration --> Distribution["User Distribution"] ``` This standardized process ensures every issued asset begins with a trusted identity. *** ## Asset Activation Flow After distribution, the asset must be activated. ```mermaid flowchart LR User User --> Wallet Wallet --> Publisher Publisher --> Blockchain Blockchain --> Active["Asset Activated"] Active --> User ``` Activation links the physical asset with its intended owner and establishes its operational state. *** ## Ownership Transfer Flow Ownership transfers are performed securely through blockchain transactions. ```mermaid sequenceDiagram participant Owner participant Wallet participant Blockchain participant NewOwner Owner->>Wallet: Transfer Request Wallet->>Blockchain: Transfer Transaction Blockchain-->>Wallet: Ownership Updated Wallet-->>NewOwner: Asset Received ``` Ownership records remain immutable and traceable on the blockchain. *** ## Reload Flow Reloadable Physical Digital Assets allow additional value to be added after issuance. ```mermaid flowchart LR User User --> Wallet Wallet --> Blockchain Blockchain --> PDA PDA --> UpdatedBalance["Updated Balance"] ``` The Physical Digital Asset reflects the updated blockchain state after synchronization. *** ## Verification Flow Merchants and wallets may verify assets before accepting them. ```mermaid flowchart LR Merchant Merchant --> Wallet Wallet --> Verification Verification --> Publisher Verification --> Blockchain Blockchain --> Verification Verification --> Wallet Wallet --> Merchant ``` Verification confirms: * Device authenticity * Publisher trust * Ownership * Asset status * Policy compliance *** ## Lifecycle Event Flow Every lifecycle event follows a standardized communication pattern. ```mermaid flowchart LR Issue Issue --> Activate Activate --> Use Use --> Transfer Transfer --> Suspend Suspend --> Recover Recover --> Retire Retire --> Destroy ``` Each state transition is recorded according to publisher policies and blockchain requirements. *** ## Offline Interaction Flow Certain operations may be performed while temporarily offline. ```mermaid flowchart LR User User --> PDA PDA --> Wallet Wallet --> LocalVerification["Local Verification"] LocalVerification --> PendingState["Pending Synchronization"] PendingState --> BlockchainSync["Sync When Online"] ``` Offline functionality depends on publisher policies, asset type, and supported risk models. *** ## Data Classification Different types of information travel through different channels. | Data Type | Primary Source | Destination | | ----------------------- | -------------------- | ----------------- | | Device Identity | Secure Element | Wallet | | Certificate | Publisher / CA | Wallet | | Asset Metadata | Publisher | Wallet | | Ownership | Blockchain | Wallet | | Transaction | Wallet | Blockchain | | Lifecycle Status | Publisher | Verification | | Authentication Response | Secure Element | Wallet | | Verification Result | Verification Service | Wallet / Merchant | Separating data types reduces unnecessary exposure and improves security. *** ## Security Considerations Every data exchange within the DCN ecosystem should be protected using appropriate security controls. Examples include: * Mutual authentication * Encrypted communication * Digital signatures * Nonce-based challenge-response * Certificate validation * Replay protection * Integrity verification * Secure session management These controls ensure that data cannot be intercepted, modified, or replayed without detection. *** ## End-to-End Interaction The following diagram summarizes a complete DCN interaction. ```mermaid sequenceDiagram participant User participant PDA participant Wallet participant Verification participant Publisher participant Blockchain participant Merchant User->>PDA: Tap PDA->>Wallet: Device Authentication Wallet->>Verification: Verify Device Verification->>Publisher: Validate Publisher Verification->>Blockchain: Verify Ownership Blockchain-->>Verification: Asset Status Verification-->>Wallet: Trusted Wallet->>Merchant: Authorize Transaction Merchant-->>User: Transaction Complete ``` This standardized flow enables independent implementations to interoperate while maintaining security and consistency. *** ## Data Flow Principles Every compliant implementation should follow these principles. | Principle | Description | | ------------------ | ------------------------------------------------------------------- | | Deterministic | Standardized interaction sequences. | | Secure | Every message is authenticated and protected. | | Minimal Disclosure | Only required information is exchanged. | | Interoperable | Independent implementations communicate seamlessly. | | Auditable | Critical operations are traceable. | | Extensible | New message types can be introduced without breaking compatibility. | *** ## Summary The DCN Data Flow model defines how information moves throughout the ecosystem, from the moment a user interacts with a Physical Digital Asset to the final verification or blockchain transaction. By standardizing communication between devices, wallets, publishers, verification services, merchants, and blockchain networks, DCN enables secure, interoperable, and scalable interactions across diverse implementations and industries. The data flow architecture ensures that every participant speaks the same protocol while preserving user security, publisher flexibility, and blockchain integrity. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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