IOHK academic researcher Dimitris Karakostas discusses securing proof-of-work ledgers with checkpointing. One of the main challenges with gaining consensus in a blockchain system is a rise of a dishonest majority. This can lead to a so called 51 percent attack which is responsible for lost funds, but most importantly, lost trust. The goal of securing the blockchain with checkpointing is to avoid trivializing the ledger maintenance, and temporary security against 51 percent attacks, while minimizing storage time and overhead. Watch the video to find our more, or read the published research: https://eprint.iacr.org/2020/173.pdf