To answer 1.), the data is not sampled to prove its there. Instead, the miner must provide a continua; cryptographic proof (called proof of replication) to prov

To answer 1.), the data is not sampled to prove its there. Instead, the miner must provide a continua; cryptographic proof (called proof of replication) to prove he has stored the data over a given period of time. https://filecoin.io/blog/filecoin-proof-system/ https://filecoin.io/blog/filecoin-proof-system/