On Apr 6, 2017 6:31 PM, "Tomas via bitcoin-dev" <bitcoin-dev@lists.linuxfoundation.org> wrote:

Bitcrust just uses a *transaction-index*, where outputs can be looked up regardless of being spent.


A network in which many nodes maintain a transaction index also enables a class of light node applications that ask peers to prove existence and spentness of TXO's.