The only proven countermeasure so far is delegated proof of stake, which has "trusted" parties doing the staking. But this goes against the idea of decentralisa

The only proven countermeasure so far is delegated proof of stake, which has "trusted" parties doing the staking. But this goes against the idea of decentralisation. Some people wonder if pure proof-of-stake is even possible. Ethereum is likely going with DPOS, yet to see a single solution to the nothing-at-stake problem.