This paper presents CoinPrune, a protocol for block pruning that is fully compatible to Bitcoin and therefore allows for gradual deployment.
CoinPrune allows joining nodes to bootstrap using a state, which has been advertised on the blockchain recently, instead of having to download and verify all blockchain data.
We maintain Bitcoin compatiblity by implementing CoinPrune as a velvet fork, i.e., instead of rejecting invalid state advertisements, we solely rely on positive state reaffirmations by multiple miners.
Our evaluation shows users can reduce their synchronization times from 5 hours to 46 minutes using CoinPrune, while downloading only 5 GiB instead of 230 GiB of blockchain data as of October 2019.
We present AnonBoot, an architecture for securely bootstrapping anonymity services seizing a public blockchain as a trust anchor.
Through periodic peer advertisements, we create a Sybil-resistant repository of privacy peers that can be directly utilized to establish circuits for onion routing networks, or that can be elected to establish small distributed anonymity services such as mixnets or cryptotumblers.
Our proof-of-concept implementation shows how AnonBoot can operate even on simple public blockchains such as Bitcoin.