ECOSYSTEM - Assumes that there are many users all with their own copy of the block chain. Any user can tell how many coins are controlled by any public key at any time. When a user wishes to spend his/her coins he/she signs a transaction and publishes it. Which broadcasts it to the rest of the network. We can also decentralize the adding of new blocks to the block BlockChain. That is, we want anyone to be able to take the transactions he/she has heard about, assemble them into a block and add them to the BlockChain.