[bringtheaction]

> Why do everybody needs to keep everything?

Because every node in the network must be able to verify all transactions all the way from the genesis block. In order to ensure that this is possible, everyone who keeps the history must keep the full history.

[tromp]

With the MimbleWimble design [1] [2], inputs may be cancelled against the outputs they spend, with no loss of security. Essentially, the entire blockchain history may be collapsed to a single mega transaction, with all coinbases as inputs and the UTXO set as outputs.

[1] http://mimblewimble.cash/20160719-OriginalWhitePaper.txt

[2] https://www.youtube.com/watch?v=ovCBT1gyk9c