07-advanced-patterns

07 - Advanced Patterns

This section demonstrates advanced usage patterns for the consent-based data provenance system, including meta-transactions, delegated consent, batch operations, and role-based access control.

Target Audience

• Developers: Implement production-ready patterns
• Architects: Design scalable consent systems
• Business Operators: Understand advanced capabilities

Examples

01 - Meta-Transactions

Gasless consent operations using signatures.

npx hardhat run examples/07-advanced-patterns/01-meta-transactions.ts --network localhost

Scenario:

Gasless consent flow:
├── User signs consent message off-chain
├── Relayer submits transaction
├── User doesn't need ETH for gas
└── Consent recorded on-chain

Demonstrates:

• EIP-712 typed data signing
• Signature-based consent
• Relayer pattern for gas abstraction

02 - Delegated Consent

Power of attorney and guardianship patterns.

npx hardhat run examples/07-advanced-patterns/02-delegated-consent.ts --network localhost

Scenario:

Healthcare delegation:
├── Patient authorizes guardian
├── Guardian consents on patient's behalf
├── Consent linked to patient
└── Delegation can be revoked

Demonstrates:

• ConsentProxy for delegation
• Guardian/POA consent
• Delegation management

03 - Batch Operations

Bulk consent and data operations.

npx hardhat run examples/07-advanced-patterns/03-batch-operations.ts --network localhost

Scenario:

Bulk consent management:
├── Give multiple consents at once
├── Revoke multiple consents
├── Validate multiple receipts
└── Register multiple data records

Demonstrates:

• KantaraConsentReceipt batch functions
• Gas-efficient bulk operations
• Transaction batching patterns

04 - RBAC Administration

Role-based access control for consent systems.

npx hardhat run examples/07-advanced-patterns/04-rbac-administration.ts --network localhost

Scenario:

Organization roles:
├── Admin manages roles
├── Auditors can query
├── Operators can record
└── Users manage own data

Demonstrates:

• ConsentAuditLog admin functions
• Authorized recorder management
• Role-based permissions

05 - Access Level Management

Granular data access control.

npx hardhat run examples/07-advanced-patterns/05-access-level-management.ts --network localhost

Scenario:

Access levels:
├── Read: View data only
├── Transform: Can process data
├── Full: Complete control
└── Time-bounded access

Demonstrates:

• DataAccessControl contract
• Tiered access levels
• Access expiration

Workflow Diagram

┌─────────────────────────────────────────────────────────────────┐
│                    Advanced Patterns                             │
├─────────────────────────────────────────────────────────────────┤
│                                                                   │
│  ┌─────────────────────────────────────────────────────────────┐ │
│  │                  META-TRANSACTIONS                           │ │
│  │    User ──▶ Sign Message ──▶ Relayer ──▶ Blockchain         │ │
│  └─────────────────────────────────────────────────────────────┘ │
│                                                                   │
│  ┌─────────────────────────────────────────────────────────────┐ │
│  │                  DELEGATED CONSENT                           │ │
│  │    Principal ──▶ Authorize ──▶ Delegate ──▶ Act on Behalf   │ │
│  └─────────────────────────────────────────────────────────────┘ │
│                                                                   │
│  ┌─────────────────────────────────────────────────────────────┐ │
│  │                  BATCH OPERATIONS                            │ │
│  │    Multiple Items ──▶ Single Transaction ──▶ Atomic Result  │ │
│  └─────────────────────────────────────────────────────────────┘ │
│                                                                   │
│  ┌─────────────────────────────────────────────────────────────┐ │
│  │                  ACCESS CONTROL                              │ │
│  │    Owner ──▶ Grant ──▶ Grantee ──▶ Time-bounded Access      │ │
│  └─────────────────────────────────────────────────────────────┘ │
│                                                                   │
└─────────────────────────────────────────────────────────────────┘

Contract Mapping

Pattern	Contract	Key Functions
Meta-transactions	(Off-chain signing)	EIP-712 signatures
Delegated consent	ConsentProxy	authorizeDelegate, delegatedConsent
Batch operations	KantaraConsentReceipt	batchRevokeConsent, batchIsConsentValid
RBAC	ConsentAuditLog	setAuthorizedRecorder
Access levels	DataAccessControl	grantAccess, checkAccess

Access Level Hierarchy

Level	Value	Capabilities
None	0	No access
Read	1	View data only
Transform	2	Read + process/transform
Full	3	Complete control

Security Considerations

• Delegated consent requires explicit authorization
• Meta-transaction signatures should include nonces
• Batch operations have size limits for gas
• Access grants should have reasonable expiration
• RBAC admin functions require careful key management

Next Steps

After completing these examples, explore:

• Compliance & Audit - Regulatory patterns
• Integration Patterns - System integration