Coreth Atomic Transaction Format

This page is meant to be the single source of truth for how we serialize atomic transactions in Coreth. This document uses the primitive serialization format for packing and secp256k1 for cryptographic user identification.

Codec ID

Some data is prepended with a codec ID (unt16) that denotes how the data should be deserialized. Right now, the only valid codec ID is 0 (0x00 0x00).

Inputs

Inputs to Coreth Atomic Transactions are either an EVMInput from this chain or a TransferableInput (which contains a SECP256K1TransferInput) from another chain. The EVMInput will be used in ExportTx to spend funds from this chain, while the TransferableInput will be used to import atomic UTXOs from another chain.

EVM Input

Input type that specifies an EVM account to deduct the funds from as part of an ExportTx.

What EVM Input Contains

An EVM Input contains an address, amount, assetID, and nonce.

• Address is the EVM address from which to transfer funds.
• Amount is the amount of the asset to be transferred (specified in nAVAX for AVAX and the smallest denomination for all other assets).
• AssetID is the ID of the asset to transfer.
• Nonce is the nonce of the EVM account exporting funds.

Gantt EVM Input Specification

+----------+----------+-------------------------+
| address  : [20]byte |                20 bytes |
+----------+----------+-------------------------+
| amount   : uint64   |                08 bytes |
+----------+----------+-------------------------+
| asset_id : [32]byte |                32 bytes |
+----------+----------+-------------------------+
| nonce    : uint64   |                08 bytes |
+----------+----------+-------------------------+
                      |                68 bytes |
                      +-------------------------+

Proto EVM Input Specification

message  {
    bytes address = 1; // 20 bytes
    uint64 amount = 2; // 08 bytes
    bytes assetID = 3; // 32 bytes
    uint64 nonce = 4;  // 08 bytes
}

EVM Input Example

Let's make an EVM Input:

• Address: 0x8db97c7cece249c2b98bdc0226cc4c2a57bf52fc
• Amount: 2000000
• AssetID: 0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
• Nonce: 0

[
    Address   <- 0x8db97c7cece249c2b98bdc0226cc4c2a57bf52fc,
    Amount    <- 0x00000000001e8480
    AssetID   <- 0xdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db
    Nonce     <- 0x0000000000000000
]
=
[
    // address:
    0x8d, 0xb9, 0x7c, 0x7c, 0xec, 0xe2, 0x49, 0xc2,
    0xb9, 0x8b, 0xdc, 0x02, 0x26, 0xcc, 0x4c, 0x2a,
    0x57, 0xbf, 0x52, 0xfc,
    // amount:
    0x00, 0x00, 0x00, 0x00, 0x00, 0x1e, 0x84, 0x80,
    // assetID:
    0xdb, 0xcf, 0x89, 0x0f, 0x77, 0xf4, 0x9b, 0x96,
    0x85, 0x76, 0x48, 0xb7, 0x2b, 0x77, 0xf9, 0xf8,
    0x29, 0x37, 0xf2, 0x8a, 0x68, 0x70, 0x4a, 0xf0,
    0x5d, 0xa0, 0xdc, 0x12, 0xba, 0x53, 0xf2, 0xdb,
    // nonce:
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
]

Transferable Input

Transferable Input wraps a SECP256K1TransferInput. Transferable inputs describe a specific UTXO with a provided transfer input.

What Transferable Input Contains

A transferable input contains a TxID, UTXOIndex AssetID and an Input.

• TxID is a 32-byte array that defines which transaction this input is consuming an output from.
• UTXOIndex is an int that defines which utxo this input is consuming in the specified transaction.
• AssetID is a 32-byte array that defines which asset this input references.
• Input is a SECP256K1TransferInput, as defined below.

Gantt Transferable Input Specification

+------------+----------+------------------------+
| tx_id      : [32]byte |               32 bytes |
+------------+----------+------------------------+
| utxo_index : int      |               04 bytes |
+------------+----------+------------------------+
| asset_id   : [32]byte |               32 bytes |
+------------+----------+------------------------+
| input      : Input    |      size(input) bytes |
+------------+----------+------------------------+
                        | 68 + size(input) bytes |
                        +------------------------+

Proto Transferable Input Specification

message TransferableInput {
    bytes tx_id = 1;       // 32 bytes
    uint32 utxo_index = 2; // 04 bytes
    bytes asset_id = 3;    // 32 bytes
    Input input = 4;       // size(input)
}

Transferable Input Example

Let's make a transferable input:

• TxID: 0x6613a40dcdd8d22ea4aa99a4c84349056317cf550b6685e045e459954f258e59
• UTXOIndex: 1
• AssetID: 0xdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db
• Input: "Example SECP256K1 Transfer Input from below"

[
    TxID      <- 0x6613a40dcdd8d22ea4aa99a4c84349056317cf550b6685e045e459954f258e59
    UTXOIndex <- 0x00000001
    AssetID   <- 0xdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db
    Input     <- 0x0000000500000000075bcd15000000020000000700000003
]
=
[
    // txID:
    0x66, 0x13, 0xa4, 0x0d, 0xcd, 0xd8, 0xd2, 0x2e,
    0xa4, 0xaa, 0x99, 0xa4, 0xc8, 0x43, 0x49, 0x05,
    0x63, 0x17, 0xcf, 0x55, 0x0b, 0x66, 0x85, 0xe0,
    0x45, 0xe4, 0x59, 0x95, 0x4f, 0x25, 0x8e, 0x59,
    // utxoIndex:
    0x00, 0x00, 0x00, 0x01,
    // assetID:
    0xdb, 0xcf, 0x89, 0x0f, 0x77, 0xf4, 0x9b, 0x96,
    0x85, 0x76, 0x48, 0xb7, 0x2b, 0x77, 0xf9, 0xf8,
    0x29, 0x37, 0xf2, 0x8a, 0x68, 0x70, 0x4a, 0xf0,
    0x5d, 0xa0, 0xdc, 0x12, 0xba, 0x53, 0xf2, 0xdb,
    // input:
    0x00, 0x00, 0x00, 0x05, 0x00, 0x00, 0x00, 0x74,
    0x6a, 0x52, 0x88, 0x00, 0x00, 0x00, 0x00, 0x01,
    0x00, 0x00, 0x00, 0x00,
]

SECP256K1 Transfer Input

A secp256k1 transfer input allows for spending an unspent secp256k1 transfer output.

What SECP256K1 Transfer Input Contains

A secp256k1 transfer input contains an Amount and AddressIndices.

• TypeID is the ID for this input type. It is 0x00000005.
• Amount is a long that specifies the quantity that this input should be consuming from the UTXO. Must be positive. Must be equal to the amount specified in the UTXO.
• AddressIndices is a list of unique ints that define the private keys that are being used to spend the UTXO. Each UTXO has an array of addresses that can spend the UTXO. Each int represents the index in this address array that will sign this transaction. The array must be sorted low to high.

Gantt SECP256K1 Transfer Input Specification

+-------------------------+-------------------------------------+
| type_id         : int   |                             4 bytes |
+-----------------+-------+-------------------------------------+
| amount          : long  |                             8 bytes |
+-----------------+-------+-------------------------------------+
| address_indices : []int |  4 + 4 * len(address_indices) bytes |
+-----------------+-------+-------------------------------------+
                          | 16 + 4 * len(address_indices) bytes |
                          +-------------------------------------+

Proto SECP256K1 Transfer Input Specification

message SECP256K1TransferInput {
    uint32 typeID = 1;                   // 04 bytes
    uint64 amount = 2;                   // 08 bytes
    repeated uint32 address_indices = 3; // 04 bytes + 04 bytes * len(address_indices)
}

SECP256K1 Transfer Input Example

Let's make a payment input with:

• TypeId: 5
• Amount: 500000000000
• AddressIndices: [0]

[
    TypeID         <- 0x00000005
    Amount         <- 500000000000 = 0x000000746a528800,
    AddressIndices <- [0x00000000]
]
=
[
    // type id:
    0x00, 0x00, 0x00, 0x05,
    // amount:
    0x00, 0x00, 0x00, 0x74, 0x6a, 0x52, 0x88, 0x00,
    // length:
    0x00, 0x00, 0x00, 0x01,
    // sig[0]
    0x00, 0x00, 0x00, 0x00,
]

Outputs

Outputs to Coreth Atomic Transactions are either an EVMOutput to be added to the balance of an address on this chain or a TransferableOutput (whcih contains a SECP256K1TransferOutput) to be moved to another chain.

The EVM Output will be used in ImportTx to add funds to this chain, while the TransferableOutput will be used to export atomic UTXOs to another chain.

EVM Output

Output type specifying a state change to be applied to an EVM account as part of an ImportTx.

What EVM Output Contains

An EVM Output contains an address, amount, and assetID.

• Address is the EVM address that will receive the funds.
• Amount is the amount of the asset to be transferred (specified in nAVAX for AVAX and the smallest denomination for all other assets).
• AssetID is the ID of the asset to transfer.

Gantt EVM Output Specification

+----------+----------+-------------------------+
| address  : [20]byte |                20 bytes |
+----------+----------+-------------------------+
| amount   : uin64    |                08 bytes |
+----------+----------+-------------------------+
| asset_id : [32]byte |                32 bytes |
+----------+----------+-------------------------+
                      |                60 bytes |
                      +-------------------------+

Proto EVM Output Specification

message  {
    bytes address = 1; // 20 bytes
    uint64 amount = 2; // 08 bytes
    bytes assetID = 3; // 32 bytes
}

EVM Output Example

Let's make an EVM Output:

• Address: 0x0eb5ccb85c29009b6060decb353a38ea3b52cd20
• Amount: 500000000000
• AssetID: 0xdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db

[
    Address   <- 0x0eb5ccb85c29009b6060decb353a38ea3b52cd20,
    Amount    <- 0x000000746a528800
    AssetID   <- 0xdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db
]
=
[
    // address:
    0xc3, 0x34, 0x41, 0x28, 0xe0, 0x60, 0x12, 0x8e,
    0xde, 0x35, 0x23, 0xa2, 0x4a, 0x46, 0x1c, 0x89,
    0x43, 0xab, 0x08, 0x59,
    // amount:
    0x00, 0x00, 0x00, 0x74, 0x6a, 0x52, 0x88, 0x00,
    // assetID:
    0xdb, 0xcf, 0x89, 0x0f, 0x77, 0xf4, 0x9b, 0x96,
    0x85, 0x76, 0x48, 0xb7, 0x2b, 0x77, 0xf9, 0xf8,
    0x29, 0x37, 0xf2, 0x8a, 0x68, 0x70, 0x4a, 0xf0,
    0x5d, 0xa0, 0xdc, 0x12, 0xba, 0x53, 0xf2, 0xdb,
]

Transferable Output

Transferable outputs wrap a SECP256K1TransferOutput with an asset ID.

What Transferable Output Contains

A transferable output contains an AssetID and an Output which is a SECP256K1TransferOutput.

• AssetID is a 32-byte array that defines which asset this output references.
• Output is a SECP256K1TransferOutput as defined below.

Gantt Transferable Output Specification

+----------+----------+-------------------------+
| asset_id : [32]byte |                32 bytes |
+----------+----------+-------------------------+
| output   : Output   |      size(output) bytes |
+----------+----------+-------------------------+
                      | 32 + size(output) bytes |
                      +-------------------------+

Proto Transferable Output Specification

message TransferableOutput {
    bytes asset_id = 1; // 32 bytes
    Output output = 2;  // size(output)
}

Transferable Output Example

Let's make a transferable output:

• AssetID: 0xdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db
• Output: "Example SECP256K1 Transfer Output from below"

[
    AssetID <- 0xdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db
    Output  <- 0x000000070000000000003039000000000000d431000000010000000251025c61fbcfc078f69334f834be6dd26d55a955c3344128e060128ede3523a24a461c8943ab0859,
]
=
[
    // assetID:
    0xdb, 0xcf, 0x89, 0x0f, 0x77, 0xf4, 0x9b, 0x96,
    0x85, 0x76, 0x48, 0xb7, 0x2b, 0x77, 0xf9, 0xf8,
    0x29, 0x37, 0xf2, 0x8a, 0x68, 0x70, 0x4a, 0xf0,
    0x5d, 0xa0, 0xdc, 0x12, 0xba, 0x53, 0xf2, 0xdb,
    // output:
    0xdb, 0xcf, 0x89, 0x0f, 0x77, 0xf4, 0x9b, 0x96,
    0x85, 0x76, 0x48, 0xb7, 0x2b, 0x77, 0xf9, 0xf8,
    0x29, 0x37, 0xf2, 0x8a, 0x68, 0x70, 0x4a, 0xf0,
    0x5d, 0xa0, 0xdc, 0x12, 0xba, 0x53, 0xf2, 0xdb,
    0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x0f, 0x42, 0x40, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
    0x00, 0x00, 0x00, 0x01, 0x66, 0xf9, 0x0d, 0xb6,
    0x13, 0x7a, 0x78, 0xf7, 0x6b, 0x36, 0x93, 0xf7,
    0xf2, 0xbc, 0x50, 0x79, 0x56, 0xda, 0xe5, 0x63,
]

SECP256K1 Transfer Output

A secp256k1 transfer output allows for sending a quantity of an asset to a collection of addresses after a specified unix time.

What SECP256K1 Transfer Output Contains

A secp256k1 transfer output contains a TypeID, Amount, Locktime, Threshold, and Addresses.

• TypeID is the ID for this output type. It is 0x00000007.
• Amount is a long that specifies the quantity of the asset that this output owns. Must be positive.
• Locktime is a long that contains the unix timestamp that this output can be spent after. The unix timestamp is specific to the second.
• Threshold is an int that names the number of unique signatures required to spend the output. Must be less than or equal to the length of Addresses. If Addresses is empty, must be 0.
• Addresses is a list of unique addresses that correspond to the private keys that can be used to spend this output. Addresses must be sorted lexicographically.

Gantt SECP256K1 Transfer Output Specification

+-----------+------------+--------------------------------+
| type_id   : int        |                        4 bytes |
+-----------+------------+--------------------------------+
| amount    : long       |                        8 bytes |
+-----------+------------+--------------------------------+
| locktime  : long       |                        8 bytes |
+-----------+------------+--------------------------------+
| threshold : int        |                        4 bytes |
+-----------+------------+--------------------------------+
| addresses : [][20]byte |  4 + 20 * len(addresses) bytes |
+-----------+------------+--------------------------------+
                         | 28 + 20 * len(addresses) bytes |
                         +--------------------------------+

Proto SECP256K1 Transfer Output Specification

message SECP256K1TransferOutput {
    uint32 typeID = 1;            // 04 bytes
    uint64 amount = 2;            // 08 bytes
    uint64 locktime = 3;          // 08 bytes
    uint32 threshold = 4;         // 04 bytes
    repeated bytes addresses = 5; // 04 bytes + 20 bytes * len(addresses)
}

SECP256K1 Transfer Output Example

Let's make a secp256k1 transfer output with:

• TypeID: 7
• Amount: 1000000
• Locktime: 0
• Threshold: 1
• Addresses:
  • 0x66f90db6137a78f76b3693f7f2bc507956dae563

[
    TypeID    <- 0x00000007
    Amount    <- 0x00000000000f4240
    Locktime  <- 0x0000000000000000
    Threshold <- 0x00000001
    Addresses <- [
        0x66f90db6137a78f76b3693f7f2bc507956dae563
    ]
]
=
[
    // typeID:
    0x00, 0x00, 0x00, 0x07,
    // amount:
    0x00, 0x00, 0x00, 0x00, 0x00, 0x0f, 0x42, 0x40,
    // locktime:
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    // threshold:
    0x00, 0x00, 0x00, 0x01,
    // number of addresses:
    0x00, 0x00, 0x00, 0x01,
    // addrs[0]:
    0x66, 0xf9, 0x0d, 0xb6, 0x13, 0x7a, 0x78, 0xf7,
    0x6b, 0x36, 0x93, 0xf7, 0xf2, 0xbc, 0x50, 0x79,
    0x56, 0xda, 0xe5, 0x63,
]

Atomic Transactions

Atomic Transactions are used to move funds between chains. There are two types ImportTx and ExportTx.

ExportTx

ExportTx is a transaction to export funds from Coreth to a different chain.

What ExportTx Contains

An ExportTx contains an typeID, networkID, blockchainID, destinationChain, inputs, and exportedOutputs.

• typeID is an int that the type for an ExportTx. The typeID for an exportTx is 1.
• networkID is an int that defines which Avalanche network this transaction is meant to be issued to. This could refer to mainnet, fuji, etc. and is different than the EVM's network ID.
• blockchainID is a 32-byte array that defines which blockchain this transaction was issued to.
• destinationChain is a 32-byte array that defines which blockchain this transaction exports funds to.
• inputs is an array of EVM Inputs to fund the ExportTx.
• exportedOutputs is an array of TransferableOutputs to be transferred to destinationChain.

Gantt ExportTx Specification

+---------------------+----------------------+-------------------------------------------------+
| typeID              : int                  |                                        04 bytes |
+---------------------+----------------------+-------------------------------------------------+
| networkID           : int                  |                                        04 bytes |
+---------------------+----------------------+-------------------------------------------------+
| blockchainID        : [32]byte             |                                        32 bytes |
+---------------------+----------------------+-------------------------------------------------+
| destinationChain    : [32]byte             |                                        32 bytes |
+---------------------+----------------------+-------------------------------------------------+
| inputs              : []EvmInput           |                          4 + size(inputs) bytes |
+---------------------+----------------------+-------------------------------------------------+
| exportedOutputs     : []TransferableOutput |                 4 + size(exportedOutputs) bytes |
+----------+----------+----------------------+-------------------------------------------------+
                                             | 80 + size(inputs) + size(exportedOutputs) bytes |
                                             +-------------------------------------------------+

ExportTx Example

Let's make an EVM Output:

• TypeID: 1
• NetworkID: 12345
• BlockchainID: 0x91060eabfb5a571720109b5896e5ff00010a1cfe6b103d585e6ebf27b97a1735
• DestinationChain: 0xd891ad56056d9c01f18f43f58b5c784ad07a4a49cf3d1f11623804b5cba2c6bf
• Inputs:
  • "Example EVMInput as defined above"
• Exportedoutputs:
  • "Example TransferableOutput as defined above"

[
    TypeID           <- 0x00000001
    NetworkID        <- 0x00003039
    BlockchainID     <- 0x91060eabfb5a571720109b5896e5ff00010a1cfe6b103d585e6ebf27b97a1735
    DestinationChain <- 0xd891ad56056d9c01f18f43f58b5c784ad07a4a49cf3d1f11623804b5cba2c6bf
    Inputs           <- [
        0xc3344128e060128ede3523a24a461c8943ab08590000000000003039000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f0000000000000001
    ]
    ExportedOutputs  <- [
        0xdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2dbdbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db0000000700000000000f42400000000000000000000000010000000166f90db6137a78f76b3693f7f2bc507956dae563
    ]
]
=
[
    // typeID:
    0x00, 0x00, 0x00, 0x01,
    // networkID:
    0x00, 0x00, 0x00, 0x04,
    // blockchainID:
    0x91, 0x06, 0x0e, 0xab, 0xfb, 0x5a, 0x57, 0x17,
    0x20, 0x10, 0x9b, 0x58, 0x96, 0xe5, 0xff, 0x00,
    0x01, 0x0a, 0x1c, 0xfe, 0x6b, 0x10, 0x3d, 0x58,
    0x5e, 0x6e, 0xbf, 0x27, 0xb9, 0x7a, 0x17, 0x35,
    // destination_chain:
    0xd8, 0x91, 0xad, 0x56, 0x05, 0x6d, 0x9c, 0x01,
    0xf1, 0x8f, 0x43, 0xf5, 0x8b, 0x5c, 0x78, 0x4a,
    0xd0, 0x7a, 0x4a, 0x49, 0xcf, 0x3d, 0x1f, 0x11,
    0x62, 0x38, 0x04, 0xb5, 0xcb, 0xa2, 0xc6, 0xbf,
    // inputs[] count:
    0x00, 0x00, 0x00, 0x01,
    // inputs[0]
    0x8d, 0xb9, 0x7c, 0x7c, 0xec, 0xe2, 0x49, 0xc2,
    0xb9, 0x8b, 0xdc, 0x02, 0x26, 0xcc, 0x4c, 0x2a,
    0x57, 0xbf, 0x52, 0xfc, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x1e, 0x84, 0x80, 0xdb, 0xcf, 0x89, 0x0f,
    0x77, 0xf4, 0x9b, 0x96, 0x85, 0x76, 0x48, 0xb7,
    0x2b, 0x77, 0xf9, 0xf8, 0x29, 0x37, 0xf2, 0x8a,
    0x68, 0x70, 0x4a, 0xf0, 0x5d, 0xa0, 0xdc, 0x12,
    0xba, 0x53, 0xf2, 0xdb, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00,
    // exportedOutputs[] count
    0x00, 0x00, 0x00, 0x01,
    // exportedOutputs[0]
    0xdb, 0xcf, 0x89, 0x0f, 0x77, 0xf4, 0x9b, 0x96,
    0x85, 0x76, 0x48, 0xb7, 0x2b, 0x77, 0xf9, 0xf8,
    0x29, 0x37, 0xf2, 0x8a, 0x68, 0x70, 0x4a, 0xf0,
    0x5d, 0xa0, 0xdc, 0x12, 0xba, 0x53, 0xf2, 0xdb,
    0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x0f, 0x42, 0x40, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
    0x00, 0x00, 0x00, 0x01, 0x66, 0xf9, 0x0d, 0xb6,
    0x13, 0x7a, 0x78, 0xf7, 0x6b, 0x36, 0x93, 0xf7,
    0xf2, 0xbc, 0x50, 0x79, 0x56, 0xda, 0xe5, 0x63,
]

ImportTx

ImportTx is a transaction to import funds to Coreth from another chain.

What ImportTx Contains

An ImportTx contains an typeID, networkID, blockchainID, destinationChain, importedInputs, and Outs.

• typeID is an int that the type for an ImportTx. The typeID for an ImportTx is 0.
• networkID is an int that defines which Avalanche network this transaction is meant to be issued to. This could refer to mainnet, fuji, etc. and is different than the EVM's network ID.
• blockchainID is a 32-byte array that defines which blockchain this transaction was issued to.
• sourceChain is a 32-byte array that defines which blockchain from which to import funds.
• importedInputs is an array of TransferableInputs to fund the ImportTx.
• Outs is an array of EVM Outputs to be imported to this chain.

Gantt ImportTx Specification

+---------------------+----------------------+-------------------------------------------------+
| typeID              : int                  |                                        04 bytes |
+---------------------+----------------------+-------------------------------------------------+
| networkID           : int                  |                                        04 bytes |
+---------------------+----------------------+-------------------------------------------------+
| blockchainID        : [32]byte             |                                        32 bytes |
+---------------------+----------------------+-------------------------------------------------+
| sourceChain         : [32]byte             |                                        32 bytes |
+---------------------+----------------------+-------------------------------------------------+
| importedInputs      : []TransferableInput  |                  4 + size(importedInputs) bytes |
+---------------------+----------------------+-------------------------------------------------+
| outs                : []EVMOutput          |                            4 + size(outs) bytes |
+----------+----------+----------------------+-------------------------------------------------+
                                             |    80 + size(importedInputs) + size(outs) bytes |
                                             +-------------------------------------------------+

ImportTx Example

Let's make an ImportTx:

• TypeID: 0
• NetworkID: 12345
• BlockchainID: 0x91060eabfb5a571720109b5896e5ff00010a1cfe6b103d585e6ebf27b97a1735
• SourceChain: 0xd891ad56056d9c01f18f43f58b5c784ad07a4a49cf3d1f11623804b5cba2c6bf
• ImportedInputs:
  • "Example TransferableInput as defined above"
• Outs:
  • "Example EVMOutput as defined above"

[
    TypeID           <- 0x00000000
    NetworkID        <- 0x00003039
    BlockchainID     <- 0x91060eabfb5a571720109b5896e5ff00010a1cfe6b103d585e6ebf27b97a1735
    SourceChain      <- 0xd891ad56056d9c01f18f43f58b5c784ad07a4a49cf3d1f11623804b5cba2c6bf
    ImportedInputs   <- [
        0x6613a40dcdd8d22ea4aa99a4c84349056317cf550b6685e045e459954f258e5900000001dbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db00000005000000746a5288000000000100000000
    ]
    Outs             <- [
        0x0eb5ccb85c29009b6060decb353a38ea3b52cd20000000746a528800dbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db
    ]
]
=
[
    // typeID:
    0x00, 0x00, 0x00, 0x00,
    // networkID:
    0x00, 0x00, 0x00, 0x04,
    // blockchainID:
    0x91, 0x06, 0x0e, 0xab, 0xfb, 0x5a, 0x57, 0x17,
    0x20, 0x10, 0x9b, 0x58, 0x96, 0xe5, 0xff, 0x00,
    0x01, 0x0a, 0x1c, 0xfe, 0x6b, 0x10, 0x3d, 0x58,
    0x5e, 0x6e, 0xbf, 0x27, 0xb9, 0x7a, 0x17, 0x35,
    // sourceChain:
    0xd8, 0x91, 0xad, 0x56, 0x05, 0x6d, 0x9c, 0x01,
    0xf1, 0x8f, 0x43, 0xf5, 0x8b, 0x5c, 0x78, 0x4a,
    0xd0, 0x7a, 0x4a, 0x49, 0xcf, 0x3d, 0x1f, 0x11,
    0x62, 0x38, 0x04, 0xb5, 0xcb, 0xa2, 0xc6, 0xbf,
    // importedInputs[] count:
    0x00, 0x00, 0x00, 0x01,
    // importedInputs[0]
    0x66, 0x13, 0xa4, 0x0d, 0xcd, 0xd8, 0xd2, 0x2e,
    0xa4, 0xaa, 0x99, 0xa4, 0xc8, 0x43, 0x49, 0x05,
    0x63, 0x17, 0xcf, 0x55, 0x0b, 0x66, 0x85, 0xe0,
    0x45, 0xe4, 0x59, 0x95, 0x4f, 0x25, 0x8e, 0x59,
    0x00, 0x00, 0x00, 0x01, 0xdb, 0xcf, 0x89, 0x0f,
    0x77, 0xf4, 0x9b, 0x96, 0x85, 0x76, 0x48, 0xb7,
    0x2b, 0x77, 0xf9, 0xf8, 0x29, 0x37, 0xf2, 0x8a,
    0x68, 0x70, 0x4a, 0xf0, 0x5d, 0xa0, 0xdc, 0x12,
    0xba, 0x53, 0xf2, 0xdb, 0x00, 0x00, 0x00, 0x05,
    0x00, 0x00, 0x00, 0x74, 0x6a, 0x52, 0x88, 0x00,
    0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00,
    // outs[] count
    0x00, 0x00, 0x00, 0x01,
    // outs[0]
    0x0e, 0xb5, 0xcc, 0xb8, 0x5c, 0x29, 0x00, 0x9b,
    0x60, 0x60, 0xde, 0xcb, 0x35, 0x3a, 0x38, 0xea,
    0x3b, 0x52, 0xcd, 0x20, 0x00, 0x00, 0x00, 0x74,
    0x6a, 0x52, 0x88, 0x00, 0xdb, 0xcf, 0x89, 0x0f,
    0x77, 0xf4, 0x9b, 0x96, 0x85, 0x76, 0x48, 0xb7,
    0x2b, 0x77, 0xf9, 0xf8, 0x29, 0x37, 0xf2, 0x8a,
    0x68, 0x70, 0x4a, 0xf0, 0x5d, 0xa0, 0xdc, 0x12,
    0xba, 0x53, 0xf2, 0xdb,
]

Credentials

Credentials have one possible type: SECP256K1Credential. Each credential is paired with an Input. The order of the credentials match the order of the inputs.

SECP256K1 Credential

A secp256k1 credential contains a list of 65-byte recoverable signatures.

What SECP256K1 Credential Contains

• TypeID is the ID for this type. It is 0x00000009.
• Signatures is an array of 65-byte recoverable signatures. The order of the signatures must match the input's signature indices.

Gantt SECP256K1 Credential Specification

+------------------------------+---------------------------------+
| type_id         : int        |                         4 bytes |
+-----------------+------------+---------------------------------+
| signatures      : [][65]byte |  4 + 65 * len(signatures) bytes |
+-----------------+------------+---------------------------------+
                               |  8 + 65 * len(signatures) bytes |
                               +---------------------------------+

Proto SECP256K1 Credential Specification

message SECP256K1Credential {
    uint32 typeID = 1;             // 4 bytes
    repeated bytes signatures = 2; // 4 bytes + 65 bytes * len(signatures)
}

SECP256K1 Credential Example

Let's make a payment input with:

• TypeID: 9
• signatures:
  • 0x0acccf47a820549a84428440e2421975138790e41be262f7197f3d93faa26cc8741060d743ffaf025782c8c86b862d2b9febebe7d352f0b4591afbd1a737f8a30010199dbf

[
    TypeID         <- 0x00000009
    Signatures     <- [
        0x0acccf47a820549a84428440e2421975138790e41be262f7197f3d93faa26cc8741060d743ffaf025782c8c86b862d2b9febebe7d352f0b4591afbd1a737f8a30010199dbf,
    ]
]
=
[
    // Type ID
    0x00, 0x00, 0x00, 0x09,
    // length:
    0x00, 0x00, 0x00, 0x01,
    // sig[0]
    0x0a, 0xcc, 0xcf, 0x47, 0xa8, 0x20, 0x54, 0x9a,
    0x84, 0x42, 0x84, 0x40, 0xe2, 0x42, 0x19, 0x75,
    0x13, 0x87, 0x90, 0xe4, 0x1b, 0xe2, 0x62, 0xf7,
    0x19, 0x7f, 0x3d, 0x93, 0xfa, 0xa2, 0x6c, 0xc8,
    0x74, 0x10, 0x60, 0xd7, 0x43, 0xff, 0xaf, 0x02,
    0x57, 0x82, 0xc8, 0xc8, 0x6b, 0x86, 0x2d, 0x2b,
    0x9f, 0xeb, 0xeb, 0xe7, 0xd3, 0x52, 0xf0, 0xb4,
    0x59, 0x1a, 0xfb, 0xd1, 0xa7, 0x37, 0xf8, 0xa3,
    0x00, 0x10, 0x19, 0x9d, 0xbf,
]

Signed Transaction

A signed transaction contains an unsigned AtomicTx and credentials.

What Signed Transaction Contains

A signed transaction contains a CodecID, AtomicTx, and Credentials.

• CodecID The only current valid codec id is 00 00.
• AtomicTx is an atomic transaction, as described above.
• Credentials is an array of credentials. Each credential corresponds to the input at the same index in the AtomicTx

Gantt Signed Transaction Specification

+---------------------+--------------+------------------------------------------------+
| codec_id            : uint16       |                                        2 bytes |
+---------------------+--------------+------------------------------------------------+
| atomic_tx           : AtomicTx     |                          size(atomic_tx) bytes |
+---------------------+--------------+------------------------------------------------+
| credentials         : []Credential |                    4 + size(credentials) bytes |
+---------------------+--------------+------------------------------------------------+
                                     |   6 + size(atomic_tx) + len(credentials) bytes |
                                     +------------------------------------------------+

Proto Signed Transaction Specification

message Tx {
    uint16 codec_id = 1;                 // 2 bytes
    AtomicTx atomic_tx = 2;              // size(atomic_tx)
    repeated Credential credentials = 3; // 4 bytes + size(credentials)
}

Signed Transaction Example

Let's make a signed transaction that uses the unsigned transaction and credential from the previous examples.

• CodecID: 0

• UnsignedTx: 0x000000000000303991060eabfb5a571720109b5896e5ff00010a1cfe6b103d585e6ebf27b97a1735d891ad56056d9c01f18f43f58b5c784ad07a4a49cf3d1f11623804b5cba2c6bf000000016613a40dcdd8d22ea4aa99a4c84349056317cf550b6685e045e459954f258e5900000001dbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db00000005000000746a5288000000000100000000000000010eb5ccb85c29009b6060decb353a38ea3b52cd20000000746a528800dbcf890f77f49b96857648b72b77f9f82937f28a68704af05da0dc12ba53f2db

• Credentials

  0x00000009000000010acccf47a820549a84428440e2421975138790e41be262f7197f3d93faa26cc8741060d743ffaf025782c8c86b862d2b9febebe7d352f0b4591afbd1a737f8a300

[
    CodecID            <- 0x0000
    UnsignedAtomic Tx  <- 0x0000000100000004ffffffffeeeeeeeeddddddddccccccccbbbbbbbbaaaaaaaa999999998888888800000001000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f000000070000000000003039000000000000d431000000010000000251025c61fbcfc078f69334f834be6dd26d55a955c3344128e060128ede3523a24a461c8943ab085900000001f1e1d1c1b1a191817161514131211101f0e0d0c0b0a09080706050403020100000000005000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f0000000500000000075bcd150000000200000007000000030000000400010203
    Credentials        <- [
        0x00000009000000010acccf47a820549a84428440e2421975138790e41be262f7197f3d93faa26cc8741060d743ffaf025782c8c86b862d2b9febebe7d352f0b4591afbd1a737f8a300,
    ]
]
=
[
    // Codec ID
    0x00, 0x00,
    // unsigned atomic transaction:
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x30, 0x39,
    0x91, 0x06, 0x0e, 0xab, 0xfb, 0x5a, 0x57, 0x17,
    0x20, 0x10, 0x9b, 0x58, 0x96, 0xe5, 0xff, 0x00,
    0x01, 0x0a, 0x1c, 0xfe, 0x6b, 0x10, 0x3d, 0x58,
    0x5e, 0x6e, 0xbf, 0x27, 0xb9, 0x7a, 0x17, 0x35,
    0xd8, 0x91, 0xad, 0x56, 0x05, 0x6d, 0x9c, 0x01,
    0xf1, 0x8f, 0x43, 0xf5, 0x8b, 0x5c, 0x78, 0x4a,
    0xd0, 0x7a, 0x4a, 0x49, 0xcf, 0x3d, 0x1f, 0x11,
    0x62, 0x38, 0x04, 0xb5, 0xcb, 0xa2, 0xc6, 0xbf,
    0x00, 0x00, 0x00, 0x01, 0x66, 0x13, 0xa4, 0x0d,
    0xcd, 0xd8, 0xd2, 0x2e, 0xa4, 0xaa, 0x99, 0xa4,
    0xc8, 0x43, 0x49, 0x05, 0x63, 0x17, 0xcf, 0x55,
    0x0b, 0x66, 0x85, 0xe0, 0x45, 0xe4, 0x59, 0x95,
    0x4f, 0x25, 0x8e, 0x59, 0x00, 0x00, 0x00, 0x01,
    0xdb, 0xcf, 0x89, 0x0f, 0x77, 0xf4, 0x9b, 0x96,
    0x85, 0x76, 0x48, 0xb7, 0x2b, 0x77, 0xf9, 0xf8,
    0x29, 0x37, 0xf2, 0x8a, 0x68, 0x70, 0x4a, 0xf0,
    0x5d, 0xa0, 0xdc, 0x12, 0xba, 0x53, 0xf2, 0xdb,
    0x00, 0x00, 0x00, 0x05, 0x00, 0x00, 0x00, 0x74,
    0x6a, 0x52, 0x88, 0x00, 0x00, 0x00, 0x00, 0x01,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
    0x0e, 0xb5, 0xcc, 0xb8, 0x5c, 0x29, 0x00, 0x9b,
    0x60, 0x60, 0xde, 0xcb, 0x35, 0x3a, 0x38, 0xea,
    0x3b, 0x52, 0xcd, 0x20, 0x00, 0x00, 0x00, 0x74,
    0x6a, 0x52, 0x88, 0x00, 0xdb, 0xcf, 0x89, 0x0f,
    0x77, 0xf4, 0x9b, 0x96, 0x85, 0x76, 0x48, 0xb7,
    0x2b, 0x77, 0xf9, 0xf8, 0x29, 0x37, 0xf2, 0x8a,
    0x68, 0x70, 0x4a, 0xf0, 0x5d, 0xa0, 0xdc, 0x12,
    0xba, 0x53, 0xf2, 0xdb,
    // number of credentials:
    0x00, 0x00, 0x00, 0x01,
    // credential[0]:
    0x00, 0x00, 0x00, 0x09, 0x00, 0x00, 0x00, 0x01,
    0x0a, 0xcc, 0xcf, 0x47, 0xa8, 0x20, 0x54, 0x9a,
    0x84, 0x42, 0x84, 0x40, 0xe2, 0x42, 0x19, 0x75,
    0x13, 0x87, 0x90, 0xe4, 0x1b, 0xe2, 0x62, 0xf7,
    0x19, 0x7f, 0x3d, 0x93, 0xfa, 0xa2, 0x6c, 0xc8,
    0x74, 0x10, 0x60, 0xd7, 0x43, 0xff, 0xaf, 0x02,
    0x57, 0x82, 0xc8, 0xc8, 0x6b, 0x86, 0x2d, 0x2b,
    0x9f, 0xeb, 0xeb, 0xe7, 0xd3, 0x52, 0xf0, 0xb4,
    0x59, 0x1a, 0xfb, 0xd1, 0xa7, 0x37, 0xf8, 0xa3,
    0x00,

UTXO

A UTXO is a standalone representation of a transaction output.

What UTXO Contains

A UTXO contains a CodecID, TxID, UTXOIndex, AssetID, and Output.

• CodecID The only valid CodecID is 00 00
• TxID is a 32-byte transaction ID. Transaction IDs are calculated by taking sha256 of the bytes of the signed transaction.
• UTXOIndex is an int that specifies which output in the transaction specified by TxID that this utxo was created by.
• AssetID is a 32-byte array that defines which asset this utxo references.
• Output is the output object that created this utxo. The serialization of Outputs was defined above.

Gantt UTXO Specification

+--------------+----------+-------------------------+
| codec_id     : uint16   |                 2 bytes |
+--------------+----------+-------------------------+
| tx_id        : [32]byte |                32 bytes |
+--------------+----------+-------------------------+
| output_index : int      |                 4 bytes |
+--------------+----------+-------------------------+
| asset_id     : [32]byte |                32 bytes |
+--------------+----------+-------------------------+
| output       : Output   |      size(output) bytes |
+--------------+----------+-------------------------+
                          | 70 + size(output) bytes |
                          +-------------------------+

Proto UTXO Specification

message Utxo {
    uint16 codec_id = 1;     // 02 bytes
    bytes tx_id = 2;         // 32 bytes
    uint32 output_index = 3; // 04 bytes
    bytes asset_id = 4;      // 32 bytes
    Output output = 5;       // size(output)
}

UTXO Example

Let’s make a UTXO from the signed transaction created above:

• CodecID: 0
• TxID: 0xf966750f438867c3c9828ddcdbe660e21ccdbb36a9276958f011ba472f75d4e7
• UTXOIndex: 0 = 0x00000000
• AssetID: 0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
• Output: "Example EVMOutput as defined above"

[
    CodecID   <- 0x0000
    TxID      <- 0xf966750f438867c3c9828ddcdbe660e21ccdbb36a9276958f011ba472f75d4e7
    UTXOIndex <- 0x00000000
    AssetID   <- 0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
    Output    <-     0x000000070000000000003039000000000000d431000000010000000251025c61fbcfc078f69334f834be6dd26d55a955c3344128e060128ede3523a24a461c8943ab0859
]
=
[
    // Codec ID:
    0x00, 0x00,
    // txID:
    0xf9, 0x66, 0x75, 0x0f, 0x43, 0x88, 0x67, 0xc3,
    0xc9, 0x82, 0x8d, 0xdc, 0xdb, 0xe6, 0x60, 0xe2,
    0x1c, 0xcd, 0xbb, 0x36, 0xa9, 0x27, 0x69, 0x58,
    0xf0, 0x11, 0xba, 0x47, 0x2f, 0x75, 0xd4, 0xe7,
    // utxo index:
    0x00, 0x00, 0x00, 0x00,
    // assetID:
    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
    0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
    // output:
    0x00, 0x00, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x30, 0x39, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0xd4, 0x31, 0x00, 0x00, 0x00, 0x01,
    0x00, 0x00, 0x00, 0x02, 0x00, 0x01, 0x02, 0x03,
    0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
    0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13,
    0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b,
    0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
    0x24, 0x25, 0x26, 0x27,
]