Almost all P2P crypto-currencies prevent double spending and similar such attacks
with a bulky “blockchain” scheme, and the ones which do not typically use some sort
of pseudo-decentralized solution to manage the transactions. Here we propose a purely
P2P crypto-currency scheme where old transactions can be forgotten by the network.
Since nodes only require the newest portion of the blockchain in order to sync with the
network, we call this portion of the chain the “mini-blockchain”. We argue that the loss
of security this trimming process incurs can be solved with a small “proof chain” and
the loss of coin ownership data is solved with a database which holds the balance of
all non-empty addresses, dubbed the “account tree”. The proof chain secures the miniblockchain
and the mini-blockchain secures the account tree. This paper will describe
the way in which these three mechanisms can work together to form a system which
provides a high level of integrity and security, yet is much slimmer than all other purely
P2P currencies. It also offers other potential benefits such as faster transactions and
lower fees, quicker network synchronization, support for high levels of traffic, more
block space for custom messages, and potentially even increased anonymity.