This is CCTP V1 version. For the latest version, see CCTP. Overview
Solana CCTP V1 programs are written in Rust and leverage the Anchor framework.
The Solana CCTP V1 protocol implementation is split into two programs:
MessageTransmitter and TokenMessengerMinter. TokenMessengerMinter
encapsulates the functionality of both TokenMessenger and TokenMinter
contracts on EVM chains. To ensure alignment with EVM contracts’ logic and
state, and to facilitate future upgrades and maintenance, the code and state of
Solana programs reflect the EVM counterparts as closely as possible.
Mainnet Program Addresses
Devnet Program Addresses
The Solana CCTP V1 source code is
available on GitHub. The
interface below serves as a reference for permissionless messaging functions
exposed by the programs.
CCTP V1 Interface
The interface below serves as a reference for permissionless messaging functions
exposed by the TokenMessengerMinter and MessageTransmitter programs. The
full IDLs can be found onchain using a block explorer.
MessageTransmitter IDL
and
TokenMessengerMinter IDL.
Please see the instruction rust files or quick-start for PDA information.
TokenMessengerMinter
Deposits and burns tokens from sender to be minted on destination domain. Minted
tokens will be transferred to mintRecipient.
Parameters
| Field | Type | Description |
|---|
| amount | u64 | Amount of tokens to deposit and burn. |
| destinationDomain | u32 | Destination domain identifier. |
| mintRecipient | Pubkey | Public Key of token account mint recipient on destination domain. Address should be the 32 byte version of the hex address in base58. See Additional Notes on mintRecipient section for more information. |
MessageSent event storageTo ensure persistent and reliable message storage, MessageSent events are stored
in accounts. MessageSent event accounts are generated client-side, passed into
the instruction call, and assigned to have the MessageTransmitter program as
the owner. Please see the
Quickstart Guide
for how to generate this account and pass it to the instruction call.For depositForBurn messages, this costs ~0.00295104 SOL in rent. This rent
is paid by the
event_rent_payer
account which can be the user or subsidized by a calling program or integrator.Once an attestation is available and the message has been received on the
destination chain, the event account can be closed and have the SOL reclaimed to
the event_rent_payer account. This is done by calling the
reclaim_event_account
instruction. This can only be called by the event_rent_payer account from when
the message was sent.Details on the message format can be found on the
Message Format page. depositForBurn but with an additional parameter,
destinationCaller. This parameter specifies which address has permission to
call receiveMessage on the destination domain for the message.
Parameters
| Field | Type | Description |
|---|
| amount | u64 | Amount of tokens to deposit and burn. |
| destinationDomain | u32 | Destination domain identifier. |
| mintRecipient | Pubkey | Public Key of mint recipient on destination domain. Address should be converted to base58. See [Mint Recipient for Solana as Source Chain Transfers](Mint Recipient for Solana as Source Chain Transfers) |
| destinationCaller | Pubkey | Public Key of caller on destination domain. Address should be converted to base58. |
Replace a BurnMessage to change the mint recipient and/or destination caller.
Allows the sender of a previous BurnMessage (created by depositForBurn or
depositForBurnWithCaller) to send a new BurnMessage to replace the original.
The new BurnMessage will reuse the amount and burn token of the original,
without requiring a new deposit.
This is useful in situations where the user specified an incorrect address and
has no way to safely mint the previously burned USDC.
Note on replaceDepositForBurnOnly the owner account of the original depositForBurn has access to call
replaceDepositForBurn. The resulting mint will supersede the original mint, as
long as the original mint has not confirmed yet onchain. When using a
third-party app/bridge that integrates with CCTP V1 to burn and mint USDC, it is
the choice of the app/bridge if and when to replace messages on behalf of users.
When sending USDC to smart contracts, be aware of the functionality that those
contracts have and their respective trust model.
| Field | Type | Description |
|---|
| originalMessage | Vec<u8> | Original message bytes (to replace). |
| originalAttestation | Vec<u8> | Original attestation bytes. |
| newDestinationCaller | Pubkey | The new destination caller, which may be the same as the original destination caller, a new destination caller, or an empty destination caller, indicating that any destination caller is valid. Address should be converted to base58. |
| newMintRecipient | Pubkey | The new mint recipient, which may be the same as the original mint recipient, or different. Address should be converted to base58. |
MessageTransmitter
Messages with a given nonce can only be broadcast successfully once for a pair
of domains. The message body of a valid message is passed to the specified
recipient for further processing.
Parameters
| Field | Type | Description |
|---|
| message | Vec<u8> | Message bytes. |
| attestation | Vec<u8> | Signed attestation of message. |
Remaining Accounts
If the receiveMessage instruction is being called with a deposit for burn
message that will be received by the TokenMessengerMinter, additional
remainingAccounts are required so they can be passed with the CPI to
TokenMessengerMinter#handleReceiveMessage:
| Account Name | PDA Seeds | PDA ProgramId | isSigner? | isWritable? | Description |
|---|
token_messenger | ["token_messenger"] | tokenMessengerMinter | false | false | TokenMessenger Program Account |
remote_token_messenger | ["remote_token_messenger", sourceDomainId] | tokenMessengerMinter | false | false | Remote token messenger account where the remote token messenger address is stored for the given source domain id |
token_minter | ["token_minter"] | tokenMessengerMinter | false | true | TokenMinter Program Account |
local_token | ["local_token", localTokenMint.publicKey] | tokenMessengerMinter | false | true | Local token account where the information for the local token (e.g. USDCSOL) being minted is stored |
token_pair | ["token_pair", sourceDomainId, sourceTokenInBase58] | tokenMessengerMinter | false | false | Token pair account where the info for the local and remote tokens are stored. sourceTokenInBase58 is the remote token that was burned converted into base58 format. |
user_token_account | N/A | N/A | false | true | User token account that will receive the minted tokens. This address must match the mintRecipient from the source chain depositForBurn call. |
custody_token_account | ["custody", localTokenMint.publicKey] | tokenMessengerMinter | false | true | Custody account that holds the pre-minted USDCSOL that can be minted for CCTP V1 usage. |
SPL.token_program_id | N/A | N/A | false | false | The native SPL token program ID. |
token_program_event_authority | ["__event_authority"] | tokenMessengerMinter | false | false | Event authority account for the TokenMessengerMinter program. Needed to emit Anchor CPI events. |
program | N/A | N/A | false | false | Program id for the TokenMessengerMinter program. |
Sends a message to the destination domain and recipient. Emits a MessageSent
event which will be attested by Circle’s attestation service.
Parameters
| Field | Type | Description |
|---|
| destinationDomain | u32 | Destination domain identifier. |
| recipient | Pubkey | Address to handle message body on destination domain. |
| messageBody | Vec<u8> | Application-specific message to be handled by recipient. |
Same as sendMessage but with an additional parameter, destinationCaller.
This parameter specifies which address has permission to call receiveMessage
on the destination domain for the message.
Parameters
| Field | Type | Description |
|---|
| destinationDomain | u32 | Destination domain identifier. |
| recipient | Pubkey | Address of message recipient on destination domain. |
| destinationCaller | Pubkey | Address of caller on the destination domain. Address should be converted to base58. |
| messageBody | Vec<u8> | Application-specific message to be handled by recipient. |
Replace a message with a new message body and/or destination caller. The
originalAttestation must be a valid attestation of originalMessage, produced
by Circle’s attestation service.
Parameters
| Field | Type | Description |
|---|
| originalMessage | Vec<u8> | Original message to replace. |
| originalAttestation | Vec<u8> | Attestation of originalMessage. |
| newMessageBody | Vec<u8> | New message body of replaced message. |
| newDestinationCaller | Pubkey | The new destination caller, which may be the same as the original destination caller, a new destination caller, or an empty destination caller (bytes32(0) or PublicKey.default, indicating that any destination caller is valid). Address should be converted to base58. |
Closes the given event account and reclaims the paid rent in SOL back to the
event_rent_payer account. This instruction can only be called by the
event_rent_payer account that paid the rent when the message was sent.
Parameters
| Field | Type | Description |
|---|
| attestation | Vec<u8> | Valid attestation for the message stored in the account. This is required to ensure the attestation service has processed and stored the message before it is deleted. |
WarningOnce this instruction is executed for a message account, the message can no
longer be read onchain. We recommend not calling this instruction until the
message has been received on the destination chain. If the message is lost
before receiving the message, it can be fetched from the attestation service
using the messages endpoint. Additional Notes
Mint Recipient for Solana as Destination Chain Transfers
When calling depositForBurn on a non-Solana chain with Solana as the
destination, the mintRecipient should be a hex encoded USDC token account
address. The token account* must exist at the time receiveMessage is called
on Solana* or else this instruction will revert. An example of converting an
address from Base58 to hex taken from the Solana quickstart tutorial in
Typescript can be seen below:
import { bs58 } from "@coral-xyz/anchor/dist/cjs/utils/bytes";
import { hexlify } from "ethers";
const solanaAddressToHex = (solanaAddress: string): string =>
hexlify(bs58.decode(solanaAddress));
Mint Recipient for Solana as Source Chain Transfers
When specifying the mintRecipient for Solana deposit_for_burn instruction
calls, the address must be given as the 32 byte version of the hex address in
base58 format. An example taken from the Solana quickstart tutorial in
Typescript can be seen below:
import { getBytes } from "ethers";
import { PublicKey } from "@solana/web3.js";
const evmAddressToBytes32 = (address: string): string =>
`0x000000000000000000000000${address.replace("0x", "")}`;
const evmAddressToBase58PublicKey = (addressHex: string): PublicKey =>
new PublicKey(getBytes(evmAddressToBytes32(addressHex)));
Program Events
Program events like
DepositForBurn
,
MintAndWithdraw
, and
MessageReceived
are emitted as Anchor CPI events. This means a self-CPI is made into the program
with the serialized event as instruction data so it is persisted in the
transaction and can be fetched later on as needed. More information can be seen
in the
Anchor implementation PR, and
an example of reading CPI events can be seen in the
solana-cctp-contracts repository.
MessageSent
events are different, as they are stored in accounts. Please see the
MessageSent Event Storage section for more info.
WHAT’S NEXT
