🌐 SAN Network Litepaper

🧭 Introduction

SAN Network is a decentralized blockchain network designed for secure, scalable, and developer-friendly transaction validation. Operating with a peer-to-peer (P2P) architecture, SAN allows nodes to synchronize, validate transactions, and maintain blockchain integrity — all without centralized control.

✨ SAN now supports smart contracts written in the developer-friendly, high-level PENA programming language.

---

🔑 Key Features

• Post-Quantum Security: Uses Dilithium2 cryptographic signatures to future-proof against quantum attacks.
• Dynamic Fee Model: Transaction fees scale with network load.
• Decentralized Peer Discovery: Nodes auto-discover peers and expand organically.
• Gossip Protocol: Maintains network health by removing unresponsive peers.
• Smart Contract Support: Build and deploy contracts in PENA, a lightweight high-level language compiled into SANVM bytecode.

---

🧱 Blockchain Architecture

🔗 Blockchain

• Immutable and verifiable chain of blocks.
• Starts with a Genesis Block.
• Each block includes:
  • Index
  • Previous Block Hash
  • Validator & Signature (Dilithium2)
  • Transactions
  • Optional Smart Contract Execution Results

💸 Transactions

• All transactions are signed using Dilithium2.
• Dynamic Fees:
  • Min: 0.01 SAN per byte.
  • Max: 0.1 SAN per byte (under high congestion).
• Signature verification is mandatory before mempool acceptance.

🖧 Nodes

Every SAN node performs:

• Peer Discovery via bootstrap servers.
• Transaction Processing & broadcasting.
• Block Validation: Each validator signs and verifies blocks.
• Gossip Updates: Share block/state info with peers.
• Smart Contract Execution via SANVM + PENA bytecode.

---

🔁 Consensus and Block Creation

• New block creation is triggered when mempool fees ≥ 500 SAN.
• Validator signs the block.
• 66% consensus required from controller nodes.
• Finalized blocks are broadcast to the network.

---

🔌 Network Communication

Uses FastAPI for REST + WebSockets for P2P events.

🔹 REST API Endpoints

• POST /sync → Blockchain sync
• POST /transaction → Submit new TX
• GET /bootstrap → Get known peers
• POST /join → Join the network

🔸 WebSocket Protocol

• PING/PONG → Peer health check
• GOSSIP → Propagate new blocks and peer status
• CONTRACT_EXEC → Broadcast smart contract invocation results

---

🔤 Smart Contracts with PENA

SAN supports high-level PENA language for smart contract development.

✍️ Example

function transferTokens(to, amount) {
  // token logic here
  print("Sending tokens to " + to)
}