Program API

Solana program interface for the Zosh bridge (Anchor framework).

Program ID: zosh4npemTuTj18MHgbn7NRihzMkTfgswTyP34LPaVx

Instructions

initialize

Initialize the bridge state and create zoZEC SPL token mint.

Authority required: Program deployer (one-time setup)

Parameters:

• mpc: Pubkey - MPC public key for validator threshold signing

Accounts:

• Creates bridge_state PDA
• Creates zec_mint PDA (8 decimals)

Example:

#![allow(unused)]
fn main() {
initialize(
    mpc: Pubkey
)
}

metadata

Update zoZEC token metadata (name, symbol, URI).

Authority required: Bridge authority only

Parameters:

• name: String - Token name
• symbol: String - Token symbol (e.g., “zoZEC”)
• uri: String - Metadata URI

mint

Mint zoZEC to recipients (threshold action, validator-only).

Authority required: MPC signature (validators)

Parameters:

• mints: Vec<MintEntry> - Batch of mint operations (max 10)

MintEntry structure:

#![allow(unused)]
fn main() {
struct MintEntry {
    recipient: Pubkey,  // Solana address to receive zoZEC
    amount: u64,        // Amount in lamports (8 decimals)
}
}

Features:

• Batch minting (up to 10 recipients per transaction)
• Automatic ATA creation if needed
• Emits MintEvent for each recipient

Requirements:

• Transaction must be signed by MPC pubkey
• Validates all recipient addresses

burn

Burn zoZEC to bridge back to Zcash (public action).

Authority required: None (anyone can burn their own zoZEC)

Parameters:

• amount: u64 - Amount to burn (8 decimals)
• zec_recipient: String - Zcash orchard address (110 characters)

Requirements:

• User must have sufficient zoZEC balance
• Zcash address must be valid orchard unified address (110 chars)

Emits:

• BurnEvent with sender, amount, and Zcash recipient
• Collectors watch for this event to trigger bridge process

Example:

#![allow(unused)]
fn main() {
burn(
    amount: 100_000_000,  // 1 ZEC (8 decimals)
    zec_recipient: "utest1..."  // 110-char address
)
}

update_mpc

Update the MPC public key (threshold action, validator-only).

Authority required: Current MPC signature (validators)

Parameters:

• mpc: Pubkey - New MPC public key

Use case: Validator set rotation, key refresh

State Accounts

bridge_state

PDA storing bridge configuration.

Seeds: ["bridge-state"]

Fields:

• authority: Pubkey - Bridge authority (for metadata updates)
• mpc: Pubkey - MPC public key (validator threshold signing)
• zec_mint: Pubkey - zoZEC SPL token mint address
• bump: u8 - PDA bump seed

zec_mint

SPL token mint for zoZEC.

Seeds: ["zec-mint"]

Properties:

• Decimals: 8 (same as Zcash)
• Mint authority: bridge_state PDA
• Freeze authority: None

Events

MintEvent

Emitted when zoZEC is minted.

#![allow(unused)]
fn main() {
struct MintEvent {
    mints: Vec<(Pubkey, u64)>,  // (recipient, amount) pairs
    timestamp: i64,
}
}

BurnEvent

Emitted when zoZEC is burned.

#![allow(unused)]
fn main() {
struct BurnEvent {
    sender: Pubkey,
    amount: u64,
    zec_recipient: String,
    timestamp: i64,
}
}

Error Codes

• InvalidMpcSigner - Transaction not signed by MPC pubkey
• InvalidRecipient - Invalid recipient address
• InvalidAmount - Amount is zero or invalid
• InvalidMint - Incorrect mint account
• InvalidBatchSize - Batch size exceeds maximum (10)
• InvalidZcashAddress - Zcash address invalid (must be 110 chars)

Deployment

Testnet (Devnet):

• Program: zosh4npemTuTj18MHgbn7NRihzMkTfgswTyP34LPaVx
• See Addresses for bridge state and mint addresses

Mainnet: Not yet deployed