Quick Start

Layer 1 — zera-core (Rust)
  Portable crypto primitives: Poseidon X5 hashing (BN254),
  incremental Merkle tree, note types, PDA derivation,
  Groth16 proof formatting. Zero Solana dependency.

Layer 2 — zera-neon (Rust → Node.js via napi-rs)
  Native bindings for high-performance Poseidon hashing
  and Merkle operations in JavaScript environments.

Layer 3 — @zera-labs/sdk (TypeScript)
  Primary integration surface. Proof generators, tx builders,
  tree state client, note storage, voucher system.

Layer 4 — @zera-labs/mcp-server
  Model Context Protocol server exposing SDK operations
  as tools for AI agents (Claude, GPT, etc.)

import { createNote, computeCommitment } from '@zera-labs/sdk'
import { generateDepositProof } from '@zera-labs/sdk/prover'
import { buildDepositTransaction } from '@zera-labs/sdk/tx'

// 1. Create a shielded note (random secret + blinding)
const note = createNote(amount, assetMint, memo)

// 2. Compute Poseidon commitment (Merkle leaf)
const commitment = computeCommitment(note)
// commitment = Poseidon(amount, secret, blinding, asset, memo[0..3])

// 3. Generate Groth16 proof
const { proof } = await generateDepositProof(
  note, wasmPath, zkeyPath
)

// 4. Build and send Solana transaction
const tx = await buildDepositTransaction({
  commitment, proof, mint, payer, amount
})
// On-chain: verify proof → insert leaf → update Merkle root

import { computeNullifier } from '@zera-labs/sdk'
import { generateWithdrawProof } from '@zera-labs/sdk/prover'
import { buildWithdrawTransaction } from '@zera-labs/sdk/tx'
import { MerkleTree } from '@zera-labs/sdk/merkle-tree'

// 1. Sync Merkle tree from chain
const tree = MerkleTree.create(24) // height=24, 16M capacity
// ... insert on-chain leaves

// 2. Compute nullifier (single-spend tag)
const nullifier = computeNullifier(note.secret, commitment)
// nullifier = Poseidon(secret, commitment)

// 3. Generate Groth16 proof
const { proof, nullifierHash } = await generateWithdrawProof(
  note, leafIndex, tree, recipientHash, wasmPath, zkeyPath
)

// 4. Build transaction
const tx = await buildWithdrawTransaction({
  proof, nullifierHash, recipientHash, mint, payer
})
// On-chain: verify proof → check nullifier PDA doesn't exist
//   → create nullifier PDA → transfer tokens

import { generateTransferProof } from '@zera-labs/sdk/prover'
import { buildTransferTransaction } from '@zera-labs/sdk/tx'

// Split a $100 note into $30 + $70
const outputNote1 = createNote(30_000_000n, usdcMint)
const outputNote2 = createNote(70_000_000n, usdcMint)

const { proof, nullifierHash, outputCommitment1, outputCommitment2 }
  = await generateTransferProof(
    inputNote, inputLeafIndex, tree,
    outputNote1, outputNote2, wasmPath, zkeyPath
  )

const tx = await buildTransferTransaction({
  proof, nullifierHash,
  outputCommitment1, outputCommitment2,
  mint, payer
})
// On-chain: verify proof → nullify input → insert 2 new leaves

// Poseidon hashing (BN254 scalar field)
import { poseidonHash, poseidonHash2 } from '@zera-labs/sdk/crypto'
const hash = poseidonHash([a, b, c])     // arbitrary-length
const node = poseidonHash2(left, right)  // Merkle node

// PDA derivation
import { derivePoolConfig, deriveVault, deriveNullifier }
  from '@zera-labs/sdk/pda'
const poolConfig = derivePoolConfig(mint, programId)
const vault = deriveVault(mint, programId)
const nullifierPDA = deriveNullifier(nullifierHash, programId)

// Note storage
import { MemoryNoteStore, FileNoteStore } from '@zera-labs/sdk'
const store = new FileNoteStore('./notes.enc')
await store.save(note, leafIndex)

// Tree state sync (on-chain → local)
import { TreeStateClient } from '@zera-labs/sdk'
const client = new TreeStateClient({ rpcUrl, cacheEndpoint })
const leaves = await client.fetchAllLeaves()

// Shielded Pool (full Groth16 ZK)
// Deposit, withdraw, relayed withdraw, shielded transfer
Program ID: B83jSQx1CT1hPRBupinaJaEkCjrfeo6Ktncu31q3ZNeX

// Private Cash (lightweight Keccak-256 vouchers)
// Commitment-based voucher system for simpler use cases
Program ID: ESQxpH9XkBQT6EVeWwAzTZD1e9NrLMrY8RPQ9SidYsgF