Block Header

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
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
timestamp	Timestamp at which the block was built	8 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_difficulty	Total accumulated difficulty since genesis block	8 bytes
scaling_difficulty	Difficulty scaling factor between the different proofs of work.	8 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: 242 bytes
-	-	-
pow	Proof of work data	For cuck(AR)oo 29: 174 bytes. For cuck(AT)oo 31: 184 bytes.
		Total: 416 bytes for C29 or 426 bytes for C31

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 fo 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: 4229bits=153bytes cuckoo_solution of C31: 4231bits=163bytes
		Sub-Total: 174 bytes for C29 and 184 bytes for C31

Example

Here is a principle example of a MimbleWimle/Grin block header. The related block is included in Mainnet chain block: 1869.

{
  "hash": "00001962e09a383b1ff232aecbce0d0d7250ca7d52d5fcc066ce73ebf9bca5c0",
  "version": 1,
  "height": 1869,
  "previous": "00001915c97bfad5bf9bb30a1035771446770502a937bd16a8c8a8f1fc6db730",
  "prev_root": "2eb356e36c03f16796dd4a6eef8cbcbeabaade84eecf013516367b376d646db7",
  "timestamp": "2019-01-17T03:05:43+00:00",
  "output_root": "b56ccc990181d04d57585d3f0163b4f636fe3208a024596d14221bfa7739e693",
  "range_proof_root": "a341b87862f430f9dda5fd0b88be175b6cc81b5e84bf6882d98cc31750b5001a",
  "kernel_root": "b3e9708378ef256d479c6b166ba0a56c26d1b2e985c5e48065dbaa8a1fa6e606",
  "nonce": 8152803443445577859,
  "edge_bits": 29,
  "cuckoo_solution": [
    13813827,
    21353671,
    43859197,
    51837783,
    56310446,
    57879705,
    85656403,
    98797541,
    99069842,
    103570486,
    116481984,
    120910172,
    132568955,
    171507199,
    182260165,
    211614977,
    212671378,
    218172868,
    220951729,
    227132075,
    238759440,
    249206477,
    280581616,
    293266345,
    300555998,
    300689284,
    318532841,
    328845581,
    341250875,
    367014677,
    391164070,
    402097316,
    417542019,
    425563418,
    436559283,
    439151219,
    443766810,
    463278212,
    466743505,
    514433563,
    528767320,
    533868566
  ],
  "total_difficulty": 1137667929019,
  "secondary_scaling": 1139,
  "total_kernel_offset": "0755f37fa67bc3d3f0a7eddec7117013be42afff3602e7480d7271fff92763f1"
}

Description

TODO