Cashmere CCTP Cross-Chain USDC Transfer Skill

Use this skill when the user asks about Cashmere cross-chain USDC transfers, CCTP contract calls, bridging between EVM / Solana / Aptos / Sui, or building transactions against the Cashmere wrapper contracts.

This skill covers source-side burns only (sending USDC cross-chain). Destination-side claim/mint is handled automatically by Cashmere's own relayers -- no user or SDK action is needed after the source transaction confirms.

Security: No private keys, mnemonics, or signer secrets are stored here. All addresses below are public on-chain data. The Gas API URL is https://gas.cashmere.exchange (production).

---

SDK Usage (Programmatic)

This skill is bundled with @cashmerelabs/cashmere-agent-sdk. If available, prefer calling the SDK directly instead of building raw transactions:

import { CashmereCCTP } from '@cashmerelabs/cashmere-agent-sdk';

const cctp = new CashmereCCTP({
  evm: { privateKey: process.env.EVM_PRIVATE_KEY },
  solana: { privateKey: process.env.SOLANA_PRIVATE_KEY },
  aptos: { privateKey: process.env.APTOS_PRIVATE_KEY },
  sui: { privateKey: process.env.SUI_PRIVATE_KEY },
});

const result = await cctp.transfer({
  from: 'ethereum',
  to: 'arbitrum',
  amount: '100',
  recipient: '0xDestinationAddress',
  version: 'v2-fast',
  feeMode: 'native',
});
// result.txHash, result.explorerUrl

Install: npm install @cashmerelabs/cashmere-agent-sdk

---

Architecture Overview

Every chain follows the same pattern:

User/Agent ──► Gas API (fee quote + signature)
          ──► Cashmere Wrapper Contract (verify sig, collect fees)
                  ──► Circle CCTP depositForBurn / depositForBurnWithHook
                          ──► Circle attestation (off-chain)
                                  ──► Cashmere relayers auto-mint on destination

---

1. Circle CCTP Domain IDs

| Domain | Chain | Native | Notes | |--------|---------------|--------|--------------------------------| | 0 | Ethereum | ETH | | | 1 | Avalanche | AVAX | | | 2 | Optimism | ETH | | | 3 | Arbitrum | ETH | | | 5 | Solana | SOL | | | 6 | Base | ETH | | | 7 | Polygon | POL | | | 8 | Sui | SUI | | | 9 | Aptos | APT | | | 10 | Unichain | ETH | | | 11 | Linea | ETH | | | 13 | Sonic | S | | | 14 | Worldchain | ETH | | | 15 | Monad | MON | | | 16 | Sei | SEI | | | 19 | HyperEVM | HYPE | Same domain as Hyperliquid Core|

---

2. CCTP Versions, Durations, and Fee Structures

V1 (Legacy Attestation-Based)

Requires Circle attestation before destination mint. Supported on EVM <-> EVM (older chains), EVM <-> Solana, EVM <-> Aptos, EVM <-> Sui, Aptos <-> Solana, Aptos <-> Sui, Sui <-> Solana.

Not supported on: Linea, Worldchain, Sei, Sonic, HyperEVM, Monad (V2-only chains).

| Source Chain | Estimated Duration | |---------------|--------------------| | Ethereum | ~15 minutes | | Arbitrum | ~15 minutes | | Base | ~15 minutes | | Optimism | ~15 minutes | | Unichain | ~15 minutes | | Polygon | ~2 minutes | | Avalanche | ~8 seconds | | Solana | ~25 seconds | | Sui | ~8 seconds | | Aptos | ~8 seconds |

Circle burn fee: 0 BPS (no Circle burn fee on V1).

V2 Fast (Threshold 1000)

Attestation-free fast finality. Supported on EVM <-> EVM and EVM <-> Solana only.

| Source Chain | Estimated Duration | |---------------|--------------------| | Ethereum | ~15 seconds | | Arbitrum | ~15 seconds | | Base | ~15 seconds | | Optimism | ~15 seconds | | Unichain | ~15 seconds | | Worldchain | ~15 seconds | | Linea | ~15 seconds | | Polygon | ~8 seconds | | Avalanche | ~8 seconds | | Sonic | ~8 seconds | | Monad | ~8 seconds | | HyperEVM | ~5 seconds | | Sei | ~5 seconds | | Solana | ~15 seconds |

Circle burn fee: Variable BPS from Circle Iris API. Fetched per route. minFinalityThreshold = 1000.

Not supported from: Avalanche, Sei, Sonic, Polygon, Solana, HyperEVM, Monad (these only support V2 Norm, not V2 Fast).

V2 Norm (Threshold 2000)

Standard finality V2. Supported on all EVM <-> EVM and EVM <-> Solana routes.

| Source Chain | Estimated Duration | |---------------|--------------------| | Ethereum | ~15 minutes | | Arbitrum | ~15 minutes | | Base | ~15 minutes | | Optimism | ~15 minutes | | Unichain | ~15 minutes | | Worldchain | ~15 minutes | | Linea | ~24 hours | | Polygon | ~8 seconds | | Avalanche | ~8 seconds | | Sonic | ~8 seconds | | Monad | ~8 seconds | | HyperEVM | ~5 seconds | | Sei | ~5 seconds | | Solana | ~25 seconds |

Circle burn fee: Variable BPS from Circle Iris API (typically lower than V2 Fast). minFinalityThreshold = 2000.

Fee Calculation Summary

Cashmere protocol fee (all chains, all versions):

total_fee = (amount * fee_bp / 10000) + static_fee

• fee_bp: On-chain basis points, max 100 (1%).
• static_fee: From the Gas API quote.
  • Native mode (isNative=true): static fee paid in native token (ETH/SOL/APT/SUI/etc.), USDC formula uses static_fee=0.
  • Stable mode (isNative=false): static fee added to USDC deduction.
• Gas drop: Currently disabled. Pass gasDropAmount=0 in all transfers.

Circle V2 burn fee (maxFee passed on-chain):

bpsTenths = ceil(minimumFee_from_iris * 10)
maxFee = ceil(amount * bpsTenths / 100000)

Where minimumFee comes from Circle Iris API (can be fractional BPS like 1.3).

---

3. Contract Addresses

EVM — CashmereCCTP Wrapper

| Chain | CashmereCCTP Address | |------------|----------------------------------------------| | Ethereum | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | Avalanche | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | Polygon | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | Arbitrum | 0x3412ef459221d1581a08dcD56Ee55B8FaeBf5eEA | | Optimism | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | Base | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | Unichain | 0xd002a7172Ac6f90657FCb918B3f7e36372a4bA80 | | Linea | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | Worldchain | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | Sei | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | Sonic | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 | | HyperEVM | 0x15b2810232ec96ff083ca6d8b785cb930d241d83 | | Monad | 0xD156fFB54871F4562744d6Be5d6321B5BffCa3B6 |

Solana — Anchor Program

| Item | Address / Key | |-----------------------------------|------------------------------------------------------| | Cashmere CCTP Program | 5RsvKL6LFq6yEFiAXEwgYHAN3aLFypeB4AaafdeDnHqM | | Address Lookup Table | 865YCTTsymGpBjLMTvjd3T3RCGT8yvxnAHhyKZqRFfLi | | Circle Message Transmitter V1 | CCTPmbSD7gX1bxKPAmg77w8oFzNFpaQiQUWD43TKaecd | | Circle Token Messenger Minter V1 | CCTPiPYPc6AsJuwueEnWgSgucamXDZwBd53dQ11YiKX3 | | Circle Message Transmitter V2 | CCTPV2Sm4AdWt5296sk4P66VBZ7bEhcARwFaaS9YPbeC | | Circle Token Messenger Minter V2 | CCTPV2vPZJS2u2BBsUoscuikbYjnpFmbFsvVuJdgUMQe | | USDC Mint | EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v |

PDAs:

• Config: seeds = ["config"] under Cashmere program
• Custodian: seeds = ["emitter"] under Cashmere program
• Custody ATA: seeds = ["__custody"] (transient, closed after burn)

Aptos — Move Module

| Item | Address | |---------------------|----------------------------------------------------------------------| | Transfer Module | 0xe49afb1896889e3e1dd7bcbb9e31d1df8221899d3d368e98588ac6b4d84b136d | | Entry Function | {module}::transfer::transfer_outer | | USDC Coin Type | 0xbae207659db88bea0cbead6da0ed00aac12edcdda169e591cd41c94180b46f3b |

Sui — Move Package

| Item | Address / Object ID | |-------------------------------|--------------------------------------------------------------------------| | Cashmere Transfer Package | 0xdf37112aacb7d3535f7b3b754b9a7b9fa1a6b3a756288dc734522c603c6f11a4 | | Cashmere Config (shared) | 0x5f1b2e205777713f44a99894d98e1e66e33dc11ff88e50108c94ee79b7ea3d67 | | Circle TokenMessengerMinter | 0x2aa6c5d56376c371f88a6cc42e852824994993cb9bab8d3e6450cbe3cb32b94e | | Message Transmitter State | 0xf68268c3d9b1df3215f2439400c1c4ea08ac4ef4bb7d6f3ca6a2a239e17510af | | TokenMessengerMinter State | 0x45993eecc0382f37419864992c12faee2238f5cfe22b98ad3bf455baf65c8a2f | | USDC Treasury | 0x57d6725e7a8b49a7b2a612f6bd66ab5f39fc95332ca48be421c3229d514a6de7 | | DenyList | 0x403 | | USDC Type | 0xdba34672e30cb065b1f93e3ab55318768fd6fef66c15942c9f7cb846e2f900e7::usdc::USDC |

USDC Addresses (per chain)

| Chain | USDC Address | |------------|-----------------------------------------------------| | Ethereum | 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 | | Avalanche | 0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E | | Polygon | 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359 | | Arbitrum | 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 | | Optimism | 0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85 | | Base | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 | | Unichain | 0x078D782b760474a361dDA0AF3839290b0EF57AD6 | | Linea | 0x176211869cA2b568f2A7D4EE941E073a821EE1ff | | Worldchain | 0x79A02482A880bCe3F13E09da970dC34dB4cD24D1 | | Sei | 0xe15fC38F6D8c56aF07bbCBe3BAf5708A2Bf42392 | | Sonic | 0x29219dd400f2Bf60E5a23d13Be72B486D4038894 | | HyperEVM | 0xb88339CB7199b77E23DB6E890353E22632Ba630f | | Monad | 0x754704Bc059F8C67012fEd69BC8A327a5aafb603 | | Solana | EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v | | Aptos | 0xbae207659db88bea0cbead6da0ed00aac12edcdda169e591cd41c94180b46f3b | | Sui | 0xdba34672e30cb065b1f93e3ab55318768fd6fef66c15942c9f7cb846e2f900e7::usdc::USDC |

---

4. Gas API — Fee Quotes and Signatures

Base URL: https://gas.cashmere.exchange

ECDSA Signature (EVM chains)

GET /getEcdsaSig_native?localDomain={domain}&destinationDomain={domain}&isNative={true|false}&isV2={true|false}

Response:

{
  "fee": "128000",
  "deadline": "1713400000",
  "signature": "0x...",
  "cctpVersion": "1"
}

Frontend converts: fee = BigInt(fee), deadline = BigInt(deadline), signature used as-is (hex string).

Ed25519 Signature (Solana, Aptos, Sui)

GET /getEd25519Sig_native?localDomain={domain}&destinationDomain={domain}&isNative={true|false}&version={1|2}

Response:

{
  "signature": "0x...",
  "message": "0x...",
  "publicKey": "0x...",
  "destinationDomain": "3",
  "fee": "128000",
  "deadline": "1713400000"
}

Frontend converts hex strings to Buffer: Buffer.from(sig.slice(2), 'hex').

Circle V2 Burn Fee (via Netlify proxy to Iris)

GET /.netlify/functions/get-burn-fees?localDomain={d}&destinationDomain={d}&threshold={1000|2000}

Proxies to: https://iris-api.circle.com/v2/burn/USDC/fees/{localDomain}/{destinationDomain}

Response:

{
  "finalityThreshold": 1000,
  "minimumFee": 1.3
}

minimumFee is in BPS (can be fractional).

---

5. EVM Transfer Pattern

ABI Functions

// V1
function transfer(TransferParams memory _params) external payable;
function transferWithPermit(TransferParams memory _params, PermitParams memory _permitParams) external payable;

// V2
function transferV2(TransferV2Params memory _params) external payable;
function transferV2WithPermit(TransferV2Params memory _params, PermitParams memory _permitParams) external payable;

TransferParams (V1)

struct TransferParams {
    uint64  amount;            // USDC amount in 6-decimal units
    uint128 fee;               // Static fee from Gas API
    uint64  deadline;          // Unix timestamp
    uint128 gasDropAmount;     // Pass 0 (gas drop currently disabled)
    uint32  destinationDomain; // Circle CCTP domain
    bytes32 recipient;         // 32-byte padded destination address
    bytes32 solanaOwner;       // Solana wallet owner (0x0 if not Solana dest)
    bool    isNative;          // true = fees in native token
    bytes   signature;         // ECDSA from Gas API
}

TransferV2Params

Same as V1 plus:

    uint256 maxFee;                // Calculated from Circle Iris minimumFee
    uint32  minFinalityThreshold;  // 1000 (fast) or 2000 (norm)
    bytes   hookData;              // Always "0x00" for standard transfers

PermitParams (for WithPermit variants)

struct PermitParams {
    uint256 value;      // USDC amount to permit
    uint256 deadline;   // Permit deadline (transfer deadline + 6000)
    bytes   signature;  // EIP-2612 permit signature
}

TypeScript Example (viem)

import { writeContract, simulateContract } from '@wagmi/core';

const GAS_API = 'https://gas.cashmere.exchange';

async function evmCctpTransfer(
  srcChain: string, // e.g. 'ethereum'
  srcDomain: number, // e.g. 0
  dstDomain: number, // e.g. 3 (arbitrum)
  amount: bigint, // USDC in 6 decimals, e.g. 100_000_000n for 100 USDC
  recipientBytes32: `0x${string}`,
  isNative: boolean,
  isV2: boolean,
) {
  // 1. Get fee quote + signature from Gas API
  const sigResp = await fetch(
    `${GAS_API}/getEcdsaSig_native?localDomain=${srcDomain}&destinationDomain=${dstDomain}&isNative=${isNative}&isV2=${isV2}`
  ).then(r => r.json());

  const fee = BigInt(sigResp.fee);
  const deadline = BigInt(sigResp.deadline);
  const signature = sigResp.signature;

  // 2. Calculate msg.value (native fee only when isNative=true)
  const value = isNative ? fee : 0n;

  // 3. Build args
  if (!isV2) {
    const args = [{
      amount,
      fee,
      deadline,
      gasDropAmount: 0n, // gas drop currently disabled
      destinationDomain: dstDomain,
      recipient: recipientBytes32,
      solanaOwner: '0x' + '0'.repeat(64),
      isNative,
      signature,
    }];

    // Simulate then send
    await simulateContract(config, {
      address: CASHMERE_CCTP_ADDRESS, // per chain
      abi: cashmereCctpAbi,
      functionName: 'transfer', // or 'transferWithPermit'
      args,
      value,
    });

    return writeContract(config, { /* same params */ });
  } else {
    // V2: fetch burn fee from Circle Iris
    const burnFee = await fetch(
      `/.netlify/functions/get-burn-fees?localDomain=${srcDomain}&destinationDomain=${dstDomain}&threshold=1000`
    ).then(r => r.json());

    const bpsTenths = Math.ceil((burnFee.minimumFee ?? 100) * 10);
    const maxFee = (amount * BigInt(bpsTenths) + 99999n) / 100000n;

    const args = [{
      amount,
      maxFee,
      fee,
      deadline,
      gasDropAmount: 0n, // gas drop currently disabled
      destinationDomain: dstDomain,
      minFinalityThreshold: 1000, // or 2000 for norm
      recipient: recipientBytes32,
      solanaOwner: '0x' + '0'.repeat(64),
      isNative,
      hookData: '0x00',
      signature,
    }];

    // Simulate then send (transferV2 or transferV2WithPermit)
  }
}

On-Chain Signature Verification (EVM)

The contract verifies ecrecover on:

keccak256(abi.encodePacked(
  localDomain,        // uint32
  destinationDomain,  // uint32
  fee,                // uint128
  deadline,           // uint64
  isNative,           // bool
  uint8(1)            // version: 1 for V1, 2 for V2
))

---

6. Solana Transfer Pattern

Instructions (Anchor IDL)

• transfer (V1): usdc_amount, destination_domain, recipient: [u8;32], solana_owner: [u8;32], fee, deadline, gas_drop_amount (pass 0), fee_is_native
• transfer_v2: Same as above plus max_fee, min_finality_threshold

Transaction Structure

A Solana CCTP transfer is a VersionedTransaction with these instructions:

1. ComputeBudgetProgram.setComputeUnitLimit({ units: 160_000 })
2. Ed25519Program.createInstructionWithPublicKey({ publicKey, message, signature }) — from Gas API response
3. program.methods.transfer(...) or program.methods.transferV2(...) — Anchor instruction

Signed by: wallet first (allows Phantom Lighthouse), then cctpMessageSigner keypair.

Uses Address Lookup Table 865YCTTsymGpBjLMTvjd3T3RCGT8yvxnAHhyKZqRFfLi for compressed V0 messages.

Key Accounts

{
  ownerTokenAccount: userUsdcAta,
  feeCollectorSolAccount: config.feeCollectorSol,
  feeCollectorUsdcAccount: config.feeCollectorUsdc,
  gasDropCollectorSolAccount: config.gasDropCollectorSol,   // still required by IDL
  gasDropCollectorUsdcAccount: config.gasDropCollectorUsdc, // still required by IDL
  owner: walletPublicKey,
  remoteTokenMessenger: PDA("remote_token_messenger", [destDomain.toString()]),
  burnSource: userUsdcAta,
  messageSentEventData: cctpMessageSigner.publicKey, // new Keypair per tx
  // V2 only:
  tokenMessengerMinterProgram: TOKEN_MESSENGER_MINTER_V2_PROGRAM_ID,
  messageTransmitterProgram: MESSAGE_TRANSMITTER_V2_PROGRAM_ID,
}

TypeScript Example

import { Program } from '@coral-xyz/anchor';
import { Ed25519Program, Keypair, PublicKey, VersionedTransaction, TransactionMessage, ComputeBudgetProgram } from '@solana/web3.js';

const GAS_API = 'https://gas.cashmere.exchange';
const PROGRAM_ID = new PublicKey('5RsvKL6LFq6yEFiAXEwgYHAN3aLFypeB4AaafdeDnHqM');

async function solanaCctpTransfer(
  connection: Connection,
  wallet: WalletAdapter,
  amount: bigint,
  destDomain: number,
  recipientBytes32: number[],
  isNative: boolean,
  isV2: boolean,
) {
  // 1. Get Ed25519 signature from Gas API
  const sigResp = await fetch(
    `${GAS_API}/getEd25519Sig_native?localDomain=5&destinationDomain=${destDomain}&isNative=${isNative}&version=${isV2 ? 2 : 1}`
  ).then(r => r.json());

  const signature = Buffer.from(sigResp.signature.slice(2), 'hex');
  const message = Buffer.from(sigResp.message.slice(2), 'hex');
  const publicKey = Buffer.from(sigResp.publicKey.slice(2), 'hex');

  // 2. Build Ed25519 verify instruction
  const signatureIx = Ed25519Program.createInstructionWithPublicKey({
    publicKey, message, signature
  });

  // 3. Build Anchor transfer instruction
  const cctpMessageSigner = new Keypair();
  const transferIx = await program.methods
    .transfer(
      new BN(amount.toString()),
      sigResp.destinationDomain,
      recipientBytes32,
      solanaOwnerBytes32,
      new BN(sigResp.fee),
      new BN(sigResp.deadline),
      new BN(0), // gas drop disabled
      isNative,
    )
    .accounts({ /* see Key Accounts above */ })
    .instruction();

  // 4. Assemble and sign
  const computeIx = ComputeBudgetProgram.setComputeUnitLimit({ units: 160_000 });
  const lookupTable = await connection.getAddressLookupTable(ALT_ADDRESS);

  const tx = new VersionedTransaction(
    new TransactionMessage({
      recentBlockhash: (await connection.getLatestBlockhash()).blockhash,
      payerKey: wallet.publicKey,
      instructions: [computeIx, signatureIx, transferIx],
    }).compileToV0Message([lookupTable.value])
  );

  tx = await wallet.signTransaction(tx);
  tx.sign([cctpMessageSigner]);

  return connection.sendTransaction(tx);
}

---

7. Aptos Transfer Pattern

Entry Function

{MODULE_ADDR}::transfer::transfer_outer

Where MODULE_ADDR = 0xe49afb1896889e3e1dd7bcbb9e31d1df8221899d3d368e98588ac6b4d84b136d

Arguments (positional)

| Index | Type | Description | |-------|------------|-------------------------------------------------| | 0 | u64 | USDC amount (6 decimals) | | 1 | u64 | Native fee amount (0 if stable mode) | | 2 | u32 | Destination domain | | 3 | address | Recipient (bytes32 hex) | | 4 | address | Solana owner (0x0 if not Solana destination) | | 5 | u64 | Static fee from Gas API | | 6 | u64 | Deadline from Gas API | | 7 | u64 | Gas drop amount (pass 0, currently disabled) | | 8 | bool | isNative | | 9 | vector<u8> | Ed25519 signature bytes |

TypeScript Example

import { InputEntryFunctionData } from '@aptos-labs/ts-sdk';

const GAS_API = 'https://gas.cashmere.exchange';
const MODULE = '0xe49afb1896889e3e1dd7bcbb9e31d1df8221899d3d368e98588ac6b4d84b136d';

async function aptosCctpTransfer(
  aptosClient: AptosClient,
  senderAddress: string,
  amount: bigint,
  destDomain: number,
  recipientBytes32: string,
  isNative: boolean,
) {
  // 1. Get Ed25519 signature from Gas API (domain 9 = Aptos)
  const sigResp = await fetch(
    `${GAS_API}/getEd25519Sig_native?localDomain=9&destinationDomain=${destDomain}&isNative=${isNative}`
  ).then(r => r.json());

  const signature = Buffer.from(sigResp.signature.slice(2), 'hex');
  const fee = sigResp.fee;
  const deadline = sigResp.deadline;

  // 2. Build transaction
  const txData: InputEntryFunctionData = {
    function: `${MODULE}::transfer::transfer_outer`,
    typeArguments: [],
    functionArguments: [
      amount.toString(),
      isNative ? BigInt(fee).toString() : '0', // native fee amount
      destDomain,
      recipientBytes32,
      '0x' + '0'.repeat(64), // solanaOwner
      fee,
      deadline,
      '0', // gas drop disabled
      isNative,
      Array.from(signature), // Pontem: Array, others: Uint8Array
    ],
  };

  // 3. Simulate and submit
  const transaction = await aptosClient.transaction.build.simple({
    sender: senderAddress,
    data: txData,
  });

  // Sign and submit via wallet adapter
}

Note: Pontem wallet requires Array.from(signature) format; other wallets (Petra, Nightly) accept Uint8Array directly.

---

8. Sui Transfer Pattern

Three-Step PTB (Programmable Transaction Block)

Sui uses a single atomic PTB with three moveCall steps:

Step 1: Cashmere prepare

target: {package}::transfer::prepare_deposit_for_burn_ticket
typeArguments: [USDC_TYPE]
arguments: [usdcCoin, nativeFeeCoin, destDomain, recipient, solanaOwner,
            fee, deadline, gasDropAmount (pass 0), isNative, signatureVector,
            configObject, clockObject]
returns: [ticket, depositInfo]

Step 2: Circle deposit

target: {tokenMessengerMinter}::deposit_for_burn::deposit_for_burn_with_package_auth
typeArguments: [USDC_TYPE, AUTH_STRUCT]
arguments: [ticket, tmmState, mtState, denyList, usdcTreasury]
returns: [burnMessage, message]

Step 3: Cashmere finalize

target: {package}::transfer::post_deposit_for_burn
arguments: [burnMessage, message, depositInfo, configObject]

TypeScript Example

import { Transaction, coinWithBalance } from '@mysten/sui/transactions';
import { SUI_CLOCK_OBJECT_ID } from '@mysten/sui/utils';

const GAS_API = 'https://gas.cashmere.exchange';
const CASHMERE_PKG = '0xdf37112aacb7d3535f7b3b754b9a7b9fa1a6b3a756288dc734522c603c6f11a4';
const CASHMERE_CONFIG = '0x5f1b2e205777713f44a99894d98e1e66e33dc11ff88e50108c94ee79b7ea3d67';
const TMM_PKG = '0x2aa6c5d56376c371f88a6cc42e852824994993cb9bab8d3e6450cbe3cb32b94e';
const MT_STATE = '0xf68268c3d9b1df3215f2439400c1c4ea08ac4ef4bb7d6f3ca6a2a239e17510af';
const TMM_STATE = '0x45993eecc0382f37419864992c12faee2238f5cfe22b98ad3bf455baf65c8a2f';
const USDC_TREASURY = '0x57d6725e7a8b49a7b2a612f6bd66ab5f39fc95332ca48be421c3229d514a6de7';
const USDC_TYPE = '0xdba34672e30cb065b1f93e3ab55318768fd6fef66c15942c9f7cb846e2f900e7::usdc::USDC';

async function suiCctpTransfer(
  suiClient: SuiClient,
  senderAddress: string,
  amount: bigint,
  destDomain: number,
  recipientBytes32: string,
  isNative: boolean,
) {
  // 1. Get Ed25519 signature from Gas API (domain 8 = Sui)
  const sigResp = await fetch(
    `${GAS_API}/getEd25519Sig_native?localDomain=8&destinationDomain=${destDomain}&isNative=${isNative}`
  ).then(r => r.json());

  const signature = Buffer.from(sigResp.signature.slice(2), 'hex');

  // 2. Build PTB
  const tx = new Transaction();

  const usdcCoin = coinWithBalance({
    type: USDC_TYPE,
    balance: amount,
  });

  const nativeCoin = tx.splitCoins(tx.gas, [
    tx.pure.u64(isNative ? BigInt(sigResp.fee).toString() : '0')
  ]);

  // Step 1: prepare
  const [ticket, depositInfo] = tx.moveCall({
    target: `${CASHMERE_PKG}::transfer::prepare_deposit_for_burn_ticket`,
    typeArguments: [USDC_TYPE],
    arguments: [
      usdcCoin, nativeCoin,
      tx.pure.u32(destDomain),
      tx.pure.address(recipientBytes32),
      tx.pure.address('0x' + '0'.repeat(64)),
      tx.pure.u64(sigResp.fee),
      tx.pure.u64(sigResp.deadline),
      tx.pure.u64('0'), // gas drop disabled
      tx.pure.bool(isNative),
      tx.pure.vector('u8', Array.from(signature)),
      tx.object(CASHMERE_CONFIG),
      tx.object(SUI_CLOCK_OBJECT_ID),
    ],
  });

  // Step 2: Circle burn
  const [burnMessage, message] = tx.moveCall({
    target: `${TMM_PKG}::deposit_for_burn::deposit_for_burn_with_package_auth`,
    typeArguments: [USDC_TYPE, `${CASHMERE_PKG}::transfer::Auth`],
    arguments: [
      ticket,
      tx.object(TMM_STATE),
      tx.object(MT_STATE),
      tx.object('0x403'),
      tx.object(USDC_TREASURY),
    ],
  });

  // Step 3: finalize
  tx.moveCall({
    target: `${CASHMERE_PKG}::transfer::post_deposit_for_burn`,
    arguments: [burnMessage, message, depositInfo, tx.object(CASHMERE_CONFIG)],
  });

  tx.setSenderIfNotSet(senderAddress);

  // 3. Sign and execute via wallet
  return suiSignAndExecuteTransaction({ transaction: tx });
}

---

9. Recipient Address Encoding

All chains encode the destination address as bytes32:

• EVM -> EVM: Left-pad 20-byte address to 32 bytes.
• Any -> Solana: Compute the recipient's USDC Associated Token Account (ATA) and encode as bytes32. Also pass solanaOwner as the wallet pubkey in bytes32. Use getAssociatedTokenAddressSync(USDC_MINT, walletPubkey).
• Any -> Aptos/Sui: The address is already 32 bytes.
• Solana owner field: Set to 0x0...0 (64 hex zeros) when destination is not Solana.

---

10. Version Routing Rules — Per Chain

Source Chain Capabilities

Which CCTP versions each chain can send from:

| Source Chain | V1 (0 BPS) | V2 Fast (1000) | V2 Norm (2000) | Possible Destinations | |--------------|------------|----------------|----------------|-------------------------------------------------| | Ethereum | Y | Y | Y | All EVM, Solana, Aptos, Sui | | Arbitrum | Y | Y | Y | All EVM, Solana, Aptos, Sui | | Base | Y | Y | Y | All EVM, Solana, Aptos, Sui | | Optimism | Y | Y | Y | All EVM, Solana, Aptos, Sui | | Unichain | Y | Y | Y | All EVM, Solana, Aptos, Sui | | Polygon | Y | N | Y | All EVM, Solana, Aptos, Sui | | Avalanche | Y | N | Y | All EVM, Solana, Aptos, Sui | | Linea | N | Y | Y | All EVM, Solana only (V2-only chain) | | Worldchain | N | Y | Y | All EVM, Solana only (V2-only chain) | | Sei | N | N | Y | All EVM, Solana only (V2-only, no V2 Fast) | | Sonic | N | N | Y | All EVM, Solana only (V2-only, no V2 Fast) | | HyperEVM | N | N | Y | All EVM, Solana only (V2-only, no V2 Fast) | | Monad | N | N | Y | All EVM, Solana only (V2-only, no V2 Fast) | | Solana | Y | N | Y | All EVM (V1+V2 Norm), Aptos (V1), Sui (V1) | | Aptos | Y | N | N | V1-legacy EVM, Solana, Sui (V1 only) | | Sui | Y | N | N | V1-legacy EVM, Solana, Aptos (V1 only) |

Destination Chain Constraints

Which versions can send to each destination:

| Destination | Can receive V1 | Can receive V2 | Notes | |--------------|---------------|----------------|----------------------------------------------| | Ethereum | Y | Y | | | Arbitrum | Y | Y | | | Base | Y | Y | | | Optimism | Y | Y | | | Unichain | Y | Y | | | Polygon | Y | Y | | | Avalanche | Y | Y | | | Linea | N | Y | V2-only destination | | Worldchain | N | Y | V2-only destination | | Sei | N | Y | V2-only destination | | Sonic | N | Y | V2-only destination | | HyperEVM | N | Y | V2-only destination | | Monad | N | Y | V2-only destination | | Solana | Y | Y | V1 from any; V2 from EVM only | | Aptos | Y | N | V1 only (from V1-legacy EVM, Solana, Sui) | | Sui | Y | N | V1 only (from V1-legacy EVM, Solana, Aptos) |

V1-Unsupported Chains (V2-only)

These chains have no V1 support — neither as source nor destination: linea, worldchain, sei, sonic, hyperevm, monad, stable, megaeth

V2 Fast-Unsupported Sources

These chains can only send V2 Norm (threshold 2000), not V2 Fast (threshold 1000): avalanche, sei, sonic, polygon, solana, hyperevm, monad

---

11. Source Code References

| Area | Path | |------------|----------------------------------------------------------| | EVM Contract | evm/src/CashmereCCTP.sol | | Solana Program | sol/programs/cashmere_cctp/src/ | | Solana IDL | sol/target/idl/cashmere_cctp.json | | Aptos Module | aptos/build/cashmere_cctp/sources/transfer.move | | Sui Module | sui/sources/transfer.move |