Merge branch 'chapter/Chapter6' into develop

ch06.asciidoc

@@ -74,13 +74,43 @@ $ bitcoind getblock 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8c
 | 4 bytes | Nonce | A counter used for the proof-of-work algorithm
 |=======
 
+=== Linking Blocks in a Chain
+
+[[chain_of_blocks]]
+.Blocks linked in a chain, by reference to the previous block header hash
+image::images/ChainOfBlocks.png["chain_of_blocks"]
+
 
-=== The Genesis Block
 === Merkle Trees
+
+A _Merkle Tree_ is a data structure created by Ralph Merkle used for efficiently summarizing and verifying the integrity of large sets of data. Merkle Trees are binary trees containing cryptographic hashes. When N data elements are hashed and summarized in a Merkle Tree, you can check to see if any one data element is included in the tree with at most +log(N)+ calculations, making this a very efficient data structure. 
+
+[[simple_merkle]]
+.Calculating the nodes in a Merkle Tree
+image::images/MerkleTree.png["merkle_tree"]
+
+[[merkle_tree_odd]]
+.An even number of data elements, by duplicating one data element
+image::images/MerkleTreeOdd.png["merkle_tree_odd"]
+
+[[merkle_tree_large]]
+.A Merkle Tree summarizing many data elements
+image::images/MerkleTreeLarge.png["merkle_tree_large"]
+
+[[merkle_tree_path]]
+.A Merkle Path used to prove inclusion of a data element
+image::images/MerkleTreePathToK.png["merkle_tree_path"]
+
 === Proof-of-Work (Mining) and Consensus
 ==== Consensus Mechanism
 ==== Proof-of-Work Algorithm
 ==== Difficulty Target and Re-Targetting
+==== Blockchain Forks
+
+[[chainforks]]
+.A blockchain showing two instances of forking
+image::images/BlockChainWithForks.png["chainforks"]
+
 ==== Highest Difficulty Chain Selection
 ==== Competition and Coinbase
 ==== Mining Pools
@@ -90,7 +120,7 @@ $ bitcoind getblock 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8c
 ==== Consensus Attacks
 ===== 51% Attack
 ===== Selfish Mining Attack
-=== Chain Forking
+
 ==== Normal Forks
 ==== Soft Forks
 ==== Hard Forks