Block Header
General format of a Block Header in a Mimblewimble/Grin:
| Field | Description | Size |
|---|---|---|
| version | Version of the block | 2 bytes |
| height | Height of this block since the genesis block (height 0) | 8 bytes |
| timestamp | Timestamp at which the block was built | 8 bytes |
| prev_hash | Hash of the block previous to this in the chain | 32 bytes |
| prev_root | Root hash of the header MMR at the previous header | 32 bytes |
| output_root | Merkle root of all the commitments in the TxHashSet | 32 bytes |
| range_proof_root | Merkle root of all range proofs in the TxHashSet | 32 bytes |
| kernel_root | Merkle root of all transaction kernels in the TxHashSet | 32 bytes |
| total_kernel_offset | Total accumulated sum of kernel offsets since genesis block. | 32 bytes |
| output_mmr_size | Total size of the output MMR after applying this block. | 8 bytes |
| kernel_mmr_size | Total size of the kernel MMR after applying this block. | 8 bytes |
| Sub-Total: 226 bytes | ||
| - | - | - |
| pow | Proof of work data | For cuck(AR)oo 29: 174 bytes. For cuck(AT)oo 32: 189 bytes. |
| Total: 400 bytes for C29 or 415 bytes for C32 |
PoW
General format of a Proof Of Work in a Mimblewimble/Grin:
| Field | Description | Size |
|---|---|---|
| total_difficulty | Total accumulated difficulty since genesis block | 8 bytes |
| secondary_scaling | Variable difficulty scaling factor for secondary proof of work | 4 bytes |
| nonce | Nonce increment used to mine this block. | 8 bytes |
| proof | Proof of work data | cuckoo_size: 1byte cuckoo_solution of C29: 42∗29 bits=153 bytes cuckoo_solution of C32: 42∗32 bits=168 bytes |
| Sub-Total: 174 bytes for C29 and 189 bytes for C32 |
Example
Here is a principle example of a Mimblewimble/Grin block header. The related block is included in Mainnet chain block: 1869.
| Offset | Field | Hex Value |
|---|---|---|
| 0 | version | 0001 |
| 2 | height | 000000000000074d |
| 10 | timestamp | 000000005c3ff107 |
| 18 | prev_hash | 00001915c97bfad5bf9bb30a1035771446770502a937bd16a8c8a8f1fc6db730 |
| 50 | prev_root | 2eb356e36c03f16796dd4a6eef8cbcbeabaade84eecf013516367b376d646db7 |
| 82 | output_root | b56ccc990181d04d57585d3f0163b4f636fe3208a024596d14221bfa7739e693 |
| 114 | range_proof_root | a341b87862f430f9dda5fd0b88be175b6cc81b5e84bf6882d98cc31750b5001a |
| 146 | kernel_root | b3e9708378ef256d479c6b166ba0a56c26d1b2e985c5e48065dbaa8a1fa6e606 |
| 178 | total_kernel_offset | 0755f37fa67bc3d3f0a7eddec7117013be42afff3602e7480d7271fff92763f1 |
| 210 | output_mmr_size | 0000000000001445 |
| 218 | kernel_mmr_size | 0000000000001130 |
| 226 | total_difficulty | 00000108e24af3bb |
| 234 | secondary_scaling | 00000473 |
| 238 | nonce | 712493895227b883 |
| 246 | edge_bits | 1d |
| 247 | edge_nonces | 43c8d2e098ba28f4f3748aab7d8be1aab3353259e6c6d4c046293f1c2f92afe7c5868bc5007fc51bae789ab3776d7efefb71547144b70ae8e764921bad8cb821a0c5d2adb455e1c406e1b2e39a2db51d7c552e4c1dd78bde1eea91f0843da6b3f1cb86e4ccb93371452b66c0ab292cd42525bcbf832fe358a3b22bcf7615e8397516ad8135a709213a77347cf4de104df5585984df0246fa03 |
| 400 |