A block is a structure that contains transaction data. It consists of:
- a block header
- a block body (transactions)
In Kaspa, each block references one or more previous blocks, to form a DAG of blocks called a blockDAG. In Bitcoin, each block references only one previous block to form a blockchain. For an introduction to Bitcoin blocks and the Bitcoin blockchain, see Mastering Bitcoin Chapter 9.
A block contains the following fields in the following order:
| Bytes | Field | Data Type | Description |
|---|---|---|---|
| variable | header | Struct: block header | The block’s block header object. |
| variable | body (transactions) | Struct: block body | The block’s body (number and list of transactions, including the coinbase transaction.) |
A measure used to approximate the storage and computational costs of transactions and blocks. Greater mass signifies greater byte size and greater computational complexity.
Mass is measured in grams:
- 1 byte = 1 gram
- 1 transaction output script = 10 grams
- 1 signature operation = 10,000 grams
A measure of the mass of a block header, as follows:
Block Header Mass [gram] = 1 * size of block header in bytes
A measure of the mass of a block body, as follows:
Block Body Mass [gram] = 1 * size of the numTxs field in bytes
+ sum_{1..numTxs}(Transaction Mass)
A measure of the mass of a block, as follows:
Block Mass [gram] = Block Header Mass
+ Block Body Mass
A block’s mass is limited to 10,000,000 grams.
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
-- header
-- ------
00000010 -- version 16
03 -- numPrevBlocks (This block points to three previous blocks)
4deee058696ebd49fa5b9d2608f1676759c72cf8463c5d782eaf522cec220000 -- hashPrevBlocks[0] (Hash of the 1st previous block, this block points to)
95821365032248be7e1b62d3d8504aa037f6ddb22f6373aca6c742e54f4b0000 -- hashPrevBlocks[1] (Hash of the 2nd previous block, this block points to)
01cf2a8ff4c5feca3c9adce431aaa0bd2cc8527ba9ad9988b327ed02e7640000 -- hashPrevBlocks[2] (Hash of the 3rd previous block, this block points to)
4e2a7018d0cb42ed8c7f1f9630bd7ce30cdecfb503414254b198b8fe763867ef -- hashMerkleRoot
91578cec482a2aebe1ae871d76bf133183cbaef5a121732fffc4365cf8ae9b7e -- acceptedIdMerkleRoot
ce4cc6742a607d25938cc2a1445c5707065bba6c9ecf34ad3251f650cbf97c1f -- utxoCommitment
81338b5e00000000 -- time
ffff7f1e -- bits
1fe540c463ebd833 -- nonce
-- body
-- ----
01 -- numTxs (This block has 1 txn - the coinbase transaction)
-- txs[1] (coinbase tx)
-- -----------
01000000 -- version 1
03 -- numTxIns (this transaction has 3 inputs)
-- txIns[0]
-- --------
4deee058696ebd49fa5b9d2608f1676759c72cf8463c5d782eaf522cec220000 -- prevTxId
ffffffff -- prevTxIndex
00 -- scriptSigLen
ffffffffffffffff -- sequence
-- txIns[1]
-- --------
95821365032248be7e1b62d3d8504aa037f6ddb22f6373aca6c742e54f4b0000 -- prevTxId
ffffffff -- prevTxIndex
00 -- scriptSigLen
ffffffffffffffff -- sequence
-- txIns[2]
-- --------
01cf2a8ff4c5feca3c9adce431aaa0bd2cc8527ba9ad9988b327ed02e7640000 -- prevTxId
ffffffff -- prevTxIndex
00 -- scriptSigLen
ffffffffffffffff -- sequence
03 -- numTxOuts (this transaction has 3 outputs)
-- txOuts[0]
-- ---------
00f2052a01000000 -- value
19 -- scriptPubKeyLen
-- scriptPubKey
-- ------------
76 -- opDup
a9 -- opHash160
-- opData_20
-- ---------
14 -- code
1234e3080bbd4135ca3b330fdc42699f2997cdc0 -- data[20]
88 -- opEqualverify
ac -- opChecksig
-- txOuts[1]
-- ---------
00f2052a01000000 -- value
19 -- scriptPubKeyLen
-- scriptPubKey
-- ------------
76 -- opDup
a9 -- opHash160
-- opData_20
-- ---------
14 -- code
1234e3080bbd4135ca3b330fdc42699f2997cdc0 -- data[20]
88 -- opEqualverify
ac -- opChecksig
-- txOuts[2]
-- ---------
00f2052a01000000 -- value
19 -- scriptPubKeyLen
-- scriptPubKey
-- ------------
76 -- opDup
a9 -- opHash160
-- opData_20
-- ---------
14 -- code
1234e3080bbd4135ca3b330fdc42699f2997cdc0 -- data[20]
88 -- opEqualverify
ac -- opChecksig
0000000000000000 -- lockTime
0100000000000000000000000000000000000000 -- subnetworkID[20]
0000000000000000 -- gas
ae812bdaaed78fafecf97d2c72899212d8e56b94287f76de8fed49e53f42b66c -- payloadHash[32]
2a -- payloadLength (VARINT)
1976a9141234e3080bbd4135ca3b330fdc42699f2997cdc088ac123ce465187f8ec82f6b61737061642f -- payload[42] (payload is 0x2a = 42 in this case)
TODO:
- Max size of block
- Illustration of block
- Links to DAG, BlockDAG, grams.
- Example