Accounts Tree

A tree storing addresses and account (i.e. balances and further fields). This tree’s root is stored in each block’s header. The account tree can be used to verify that an account in a certain state was part of a certain block. And account tree is composed of account tree nodes using Ethereum’s Merkle Patricia Trie Specification.

Accounts and Transactions

Rules:

• It forbidden to spend funds received in the same block
• Transaction ordering: in general block order, but currently ignored because it is irrelevant when one can only spend funds one has received before the current block already.

Adding Accounts to the Accounts Tree

Procedure:

1. subtract from all sender accounts
2. add to all recipient accounts
3. create contract accounts
4. prune contract accounts (must be pruned when empty)

Position in tree is unrelated to position in block body.

Accounts Tree Nodes

An accounts tree node can be of two types: branch or terminal. Branch nodes build the tree structure while the terminal nodes are the leaves of the tree.

Accounts Tree Node Branch

The tree structure is composed of prefixes to decend and find the correct account in a terminal node. A branch is composed of a prefix and children:

And then for each child a structure as follows is attached:

Accounts Tree Node Terminal

The terminal node is the leave node of the account tree, it contains the actual account.