Obscura — Post-Quantum Secure Privacy Platform

Obscura is a post-quantum secure intent settlement system combining:

• WOTS+ — Winternitz One-Time Signatures for quantum-resistant authorization
• SIP — Shielded Intent Protocol for privacy-preserving transactions
• Stealth addresses — Unlinkable payments
• Pedersen commitments — Hidden amounts
• Arcium MPC — Confidential computing with encrypted data
• Light Protocol ZK Compression — ~1000x cheaper Solana storage

Base URL: https://api.obscura-app.com

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Quick Orientation

What you need	Endpoint
Deposit to privacy vault	POST /api/v1/deposit
Withdraw privately	POST /api/v1/withdraw
Check privacy status	GET /api/v1/privacy/status
Query vault balance	POST /api/v1/balance

---

Deployed Contracts

Solana Devnet

• Program ID: GG9U34H1xXkuzvv8Heoy4UWav5vUgrQFEVwrYMi84QuE
• Vault PDA: 6owJu2yXoPvTbM67XwmRguVRQhCADaswHkAVhVHSvoH7

Sepolia Testnet

• SIPVault: 0xc4937Ba6418eE72EDABF72694198024b5a3599CC
• SIPSettlement: 0x88dA9c5D9801cb33615f0A516eb1098dF1889DA9

---

Privacy Architecture

The Privacy Problem with Basic Vaults

Basic Vault (Vulnerable):
- Deposit: User_A → Vault (User_A visible)
- Withdraw: User_A calls withdraw() → Vault → Recipient
- ❌ User_A visible as withdrawal initiator
- ❌ Vault PDA visible — enables graph tracing

Obscura Solution: Direct Transfer + Off-Chain Balance

Obscura (True Privacy):
1. DEPOSIT: User → Vault (pooled, unlinkable)
2. VERIFICATION: Off-chain (Arcium MPC, encrypted)
3. WITHDRAWAL: Relayer → Recipient (direct, NO vault PDA!)

Key insight: Vault PDA is public but safe because:

• Only receives deposits (never sends withdrawals)
• Direct transfer breaks the link
• Cannot trace depositor → recipient

---

Core Endpoints

Health Check

GET /health

{
  "status": "healthy",
  "services": { "auth": "ready", "aggregator": "ready", "solana": "ready", "evm": "ready" }
}

Privacy Status

GET /api/v1/privacy/status

Returns Arcium MPC and Light Protocol configuration:

{
  "features": {
    "pedersenCommitments": true,
    "stealthAddresses": true,
    "batchSettlement": true,
    "wotsAuthorization": true,
    "confidentialComputing": true
  },
  "arcium": {
    "configured": true,
    "clusterOffset": "456",
    "version": "v0.6.3",
    "programId": "arcaborPMqYhZbLqPKPRXpBKyCMgH8kApNoxp4cLKg"
  },
  "lightProtocol": {
    "zkCompression": true,
    "compressedPDAs": true,
    "costSavings": "~1000x cheaper storage"
  }
}

Deposit

POST /api/v1/deposit

Minimum: 0.0003 SOL or 0.0003 ETH

Request:

{
  "network": "solana-devnet",
  "token": "native",
  "amount": "5000000"
}

Response:

{
  "success": true,
  "depositNote": {
    "commitment": "0x...",
    "nullifier": "abc123...",      // SECRET — save locally!
    "nullifierHash": "0x...",
    "secret": "def456...",         // SECRET — save locally!
    "amount": "5000000",
    "token": "native",
    "chainId": "solana-devnet"
  },
  "txHash": "5YiJ1SCm3C...",
  "vaultAddress": "6owJu2yXoPvTbM67XwmRguVRQhCADaswHkAVhVHSvoH7"
}

⚠️ IMPORTANT: Save nullifier and secret — required for withdrawal!

Query Balance

POST /api/v1/balance

Query Arcium cSPL off-chain balance (Solana only):

Request:

{
  "commitment": "b4083a81a64f7bf5...",
  "chainId": "solana-devnet"
}

Response:

{
  "success": true,
  "balance": "1200000000",
  "pendingBalance": "0",
  "confidentialAccount": "5599a875...",
  "encrypted": true,
  "deposits": 1,
  "withdrawals": 0
}

Withdraw

POST /api/v1/withdraw

Request:

{
  "commitment": "0x...",
  "nullifierHash": "0x...",
  "recipient": "ECYks1hYG3xVRyYpwaesqGrkpj9ZQh1R6S3T3KXDrhrA",
  "amount": "5000000",
  "chainId": "solana-devnet"
}

Response:

{
  "success": true,
  "requestId": "3ae33176109d737e",
  "status": "pending"
}

After relayer executes (Solana with ZK Compression):

{
  "success": true,
  "requestId": "3ae33176109d737e",
  "txHash": "5fmG66Xz8Uyv5Sfu6QfPUYYzcNaLPfgWVSZV5rijKmJKQ...",
  "status": "completed",
  "zkCompressed": true,
  "compressionSignature": "3Ag8rUJB6tswcHubJ62aspEkJFf3QvShwCJPa4jgUsX..."
}

---

Deposit Note Structure

interface DepositNote {
  commitment: string;    // Public — hash of secrets, stored on-chain
  nullifier: string;     // SECRET — random 32 bytes, proves ownership
  nullifierHash: string; // Public — hash(nullifier), replay protection
  secret: string;        // SECRET — random 32 bytes, part of commitment
  amount: string;        // Amount deposited
  token: string;         // Token type
  chainId: string;       // Chain identifier
  timestamp: number;      // Deposit time
}

---

Relayer Service

Fee Structure (Tiered)

Amount	Fee Rate	Example
0-10 SOL/ETH	0.10%	10 SOL → 0.01 SOL
10-100 SOL/ETH	0.08%	100 SOL → 0.08 SOL
100-1000 SOL/ETH	0.06%	1000 SOL → 0.6 SOL
1000+ SOL/ETH	0.05%	10000 SOL → 5 SOL

Minimum fees: 0.0001 SOL, 0.00001 ETH

---

Supported Chains

Chain	Chain ID	Status
Solana Devnet	solana-devnet	✅ Active
Sepolia	sepolia	✅ Active
Ethereum	ethereum	🔜 Soon
Polygon	polygon	🔜 Soon

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Privacy Levels

Level	Description	Use Case
transparent	All data visible	Debugging, auditing
shielded	Maximum privacy (default)	Private transfers
compliant	Viewing keys enabled	Regulatory compliance

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Arcium MPC Integration

Capabilities

Use Case	Description
Confidential Solver Auctions	Fair solver selection without bid visibility
Intent Encryption	Private amounts prevent front-running
Batch Optimization	Encrypted routing optimization
Compliance Disclosure	Sealed viewing keys for regulators

Version

• Arcium: v0.6.3, cluster offset 456
• SDK: @arcium-hq/client v0.6.1

View Transactions

• Arcium Explorer: https://explorer.arcium.com/tx/<mxe_id>?cluster=devnet

---

ZK Compression (Light Protocol)

Cost Savings

Storage Type	1000 Records	Cost
Traditional	1000 accounts	~2 SOL
ZK Compressed	1 Merkle tree	~0.002 SOL

ETH Privacy

ZK Compression is disabled for ETH to prevent cross-chain data correlation that could break privacy.

---

Complete Flow Example

Private SOL Transfer

# Step 1: Deposit
curl -X POST https://api.obscura-app.com/api/v1/deposit \
  -H "Content-Type: application/json" \
  -d '{"network": "solana-devnet", "token": "native", "amount": "5000000"}'
# Save the depositNote! (nullifier and secret)

# Step 2: Request withdrawal (later, different device/IP)
curl -X POST https://api.obscura-app.com/api/v1/withdraw \
  -H "Content-Type: application/json" \
  -d '{
    "commitment": "0x...",
    "nullifierHash": "0x...",
    "recipient": "ECYks1hYG3xVRyYpwaesqGrkpj9ZQh1R6S3T3KXDrhrA",
    "amount": "5000000",
    "chainId": "solana-devnet"
  }'

---

Error Codes

HTTP	Error	Description
400	Missing required fields	Request validation failed
400	Nullifier already used	Double-spend attempt
400	Amount too low	Below minimum (0.0003)
404	Not found	Resource not found
500	Relayer execution failed	On-chain tx failed

---

Additional Resources

Reference Files

For cryptographic details, advanced patterns, and integration guides:

• references/deposit-withdraw-flows.md — Step-by-step flow documentation
• references/arcium-integration.md — Arcium MPC detailed integration
• references/cryptographic-primitives.md — WOTS+, Pedersen, stealth addresses