headers

The headers message sends one or more block headers to a node which previously requested certain headers with a getheaders message. A headers message can be empty.

Name

Data Type

Bytes

Description

headers

vector<BlockHeader>

Varies

Block headers: each 140-byte block header is in the format described in the block headers section. Number of block headers up to a maximum of 2,000. Note: headers-first sync assumes the sending node will send the maximum number of headers whenever possible.

The annotated hexdump below shows a “headers” message. (The message header has been omitted.)

01 ................................. Header count: 1

02000000 ........................... Block version: 2
b6ff0b1b1680a2862a30ca44d346d9e8
910d334beb48ca0c0000000000000000 ... Hash of previous block's header
9d10aa52ee949386ca9385695f04ede2
70dda20810decd12bc9b048aaab31471 ... Merkle root
084c799cd551dd1d8d5c5f9a5d593b2e
931f5e36122ee5c793c1d08a19839cc0 ... Witness Merkle root
95d4c628d3aa681f4f0895281921b339
4f61d7781e9861fba5ecb403311832f4 ... Finalizer commits Merkle root
24d95a54 ........................... [Unix time][unix epoch time]: 1415239972
30c31b18 ........................... Target (bits)