Consensus is PoW mining based on a random reads into a large snow field. This makes the mining more IO bandwidth intensive than CPU/GPU/ASIC. Sure, someone could build something that does more raw IOPS than a regularly available NVME drive or DDR4 stick, but it probably won’t be much more price effective. This means mining will be in the hands of a large number of people. Hopefully.

In more detail, the hashing algorithm is based on doing reads into the large snow field files. They started at 1gb, but are up to 256gb right now. Each hash operation requires 6 lookups into that field. The field is generated using a nightmarish algorithm that ensures that you can’t just quickly make a few chunks of the file in memory as you need them. People can generate the file, the algorithm is checked in, but it writes sectors over and over as it progresses through its rounds so it takes some time. Most people download the torrents. But the merkle roots of these files are checked in as well, so nodes and clients don’t need these huge files to validate blocks. The block headers include a merkle proof for each of those reads to prove the data was there as included in the headers. It makes the headers a few kb larger than other coins but I think it is a reasonable trade-off.