Zcash Evaluation

Zcash Proving System Evaluation

Evaluation of Zcash’s proving system and potential integration with SIP Protocol.

Overview

Zcash pioneered shielded transactions using zero-knowledge proofs. SIP evaluates integration points while maintaining its application-layer approach.

Zcash Privacy Features

Shielded Pools

Pool	Protocol	Status
Sprout	BCTV14	Deprecated
Sapling	Groth16	Active
Orchard	Halo 2	Latest

Key Properties

Property	Zcash	SIP
Amount privacy	Yes	Yes (Pedersen)
Sender privacy	Yes	Yes (Stealth)
Recipient privacy	Yes	Yes (Stealth)
On-chain shielding	Yes	No (app layer)
Trusted setup	Yes (Sapling) / No (Orchard)	No (Noir)

Integration Options

Option 1: Zcash as Destination

Use Zcash shielded pool as swap destination:

Ethereum → SIP → NEAR Intents → Zcash (shielded)

Pros:

Leverage Zcash’s proven privacy
Full on-chain shielding

Cons:

Requires Zcash RPC access
Limited to ZEC as output

Option 2: ZcashRPCClient

SIP includes Zcash RPC client for shielded operations:

import { ZcashRPCClient } from '@sip-protocol/sdk'

const client = new ZcashRPCClient({
  host: '127.0.0.1',
  port: 8232,
  username: process.env.ZCASH_RPC_USER,
  password: process.env.ZCASH_RPC_PASS
})

// Create HD account
const { account } = await client.createAccount()

// Get unified address
const { address } = await client.getAddressForAccount(
  account,
  ['sapling', 'orchard']
)

// Send shielded transaction (returns an operation ID for tracking)
const operationId = await client.sendShielded({
  fromAddress: address,
  recipients: [{ address: recipientZAddress, amount: 1.5, memo: 'Private transfer' }]
})
const operation = await client.waitForOperation(operationId)
console.log('Transaction ID:', operation.result?.txid)

Option 3: Proof Verification

Verify Zcash proofs within SIP:

// Not implemented - future consideration
const isValid = await verifyZcashProof(proof, publicInputs)

Halo 2 Analysis

Orchard uses Halo 2 for trustless proofs:

Advantages

Feature	Benefit
No trusted setup	Eliminates ceremony risk
Recursive proofs	Proof aggregation
IPA commitments	Smaller proof size

Considerations

Aspect	Note
Complexity	Steep learning curve
Performance	Slower than Groth16
Ecosystem	Less tooling than SNARKs

Decision: Application Layer

SIP chose application-layer privacy over protocol integration:

Rationale

No blockchain changes - Works with existing chains
Flexibility - Not tied to single privacy technology
Speed - Faster iteration than protocol changes
Multi-chain - Privacy across all supported chains

Tradeoffs

Approach	Protocol Level	Application Level
Privacy strength	Stronger	Good
Implementation	Harder	Easier
Blockchain changes	Required	None
Flexibility	Lower	Higher

Zcash RPC Methods

Account Management

// Create account (modern HD approach)
const { account } = await client.createAccount()

// Get address for account
const { address } = await client.getAddressForAccount(
  account,
  ['sapling'], // Receiver types
  0            // Diversifier index
)

Deprecated Methods

Deprecated	Replacement
`generateShieldedAddress()`	`createAccount()` + `getAddressForAccount()`
`z_getnewaddress`	Account-based approach

Shielded Transactions

// Get balance for an account (per-pool breakdown)
const balance = await client.getAccountBalance(account)

// List unspent shielded notes (incoming/received funds)
const notes = await client.listUnspent()

// Send shielded (returns an operation ID; resolve to a txid via waitForOperation)
const operationId = await client.sendShielded({
  fromAddress: sender,
  recipients: [{ address: recipient, amount: 10, memo: 'Optional memo' }]
})
const { result } = await client.waitForOperation(operationId)
console.log('txid:', result?.txid)

Unified Addresses

Zcash Unified Addresses (ZIP-316) combine multiple receiver types:

u1...
├── Orchard receiver (if available)
├── Sapling receiver
└── Transparent receiver (optional)

// Generate unified address
const { address } = await client.getAddressForAccount(
  account,
  ['orchard', 'sapling', 'p2pkh'] // Include all receiver types
)

Performance Comparison

Metric	Zcash Sapling	Zcash Orchard	SIP (Noir)
Proof gen	~40s	~2s	~3s
Proof size	~1KB	~5KB	~200B
Verify	~10ms	~10ms	~10ms
Trusted setup	Yes	No	No