Merge branch 'chapter/Chapter6' into develop

ch06.asciidoc

@@ -55,15 +55,23 @@ $ bitcoind getblock 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8c
 |Size| Field | Description
 | 4 bytes | Magic Number | A constant (0xD9B4BEF9) used to easily recognize bitcoin blocks
 | 4 bytes | Block Size | The size of the block, in bytes, following this field
-| Block Header ||
+| 80 bytes | Block Header | Several fields form the block header (see below)
+| 1-9 bytes (VarInt) | Transaction Counter | How many transactions follow
+| Variable | Transactions | The transactions recorded in this block
+|=======
+
+
+[[block_structure]]
+.The structure of the block header
+[options="header"]
+|=======
+|Size| Field | Description
 | 4 bytes | Version | A version number to track software/protocol upgrades
 | 32 bytes | Previous Block Hash | A reference to the hash of the previous (parent) block in the chain
 | 32 bytes | Merkle Root | A hash of the root of the Merkle-Tree of this block's transactions
 | 4 bytes | Timestamp | The approximate creation time of this block (seconds from Unix Epoch)
 | 4 bytes | Difficulty Target | The proof-of-work algorithm difficulty target for this block
 | 4 bytes | Nonce | A counter used for the proof-of-work algorithm
-| 1-9 bytes (VarInt) | Transaction Counter | How many transactions follow
-| Variable | Transactions | The transactions recorded in this block
 |=======