Block Model

An introduction and overview of the VeChainThor blockchain block model.

VeChainThor defines a block in Golang as:

// block.go

type Block struct {
	header *Header
	txs    tx.Transactions
}

type Header struct {
	body headerBody
}

type headerBody struct {
	ParentID     thor.Bytes32
	Timestamp    uint64
	GasLimit     uint64
	Beneficiary  thor.Address
	GasUsed      uint64
	BaseFee      *big.Int
	TotalScore   uint64
	TxsRoot      thor.Bytes32
	StateRoot    thor.Bytes32
	ReceiptsRoot thor.Bytes32
	Signature    []byte
	Alpha        []byte
	COM          bool
}

type Transactions []*Transaction

Fields within the headerBody, $\Gamma$, are defined as:

• ParentID - the ID of the parent block

• Timestamp - the block time

• GasLimit - the maximum amount of gas that all transactions inside the block are allowed to consume

• Beneficiary - the address assigned by the block generator to receive reward (in VTHO)

• GasUsed - the actual amount of gas used within the block

• BaseFee - the mandatory minimum fee required for including a transaction within the block

• TotalScore - the accumulated witness number of the chain branch headed by the block. See Trunk for more detail.

• TxsRoot - root hash of the transaction in the payload

• StateRoot - root hash for the global state after applying changes in this block

• ReceiptsRoot - hash of the transaction receipts trie

• Signature - signature of block builder

• Alpha - an input into the Verifiable Random Function (VRF)

• COM - a boolean indicating whether the packer votes commit

The block ID (thor.Bytes32) can be computed as:

$BlkID = h \circ (hash(\Gamma - sig )[4:]$

where $h$ is the block number stored as a uint32 and $[4:]$ the operation that discards the first four bytes.