Blockchain technology is just the meat of Bitcoin. And the computational complexity PH three-layer structure is the backbone of Bitcoin. The backbone of the blockchain can only be built with three layers of pH technology. Blockchain refers to the UTXO/POW/longest chain where the tx/block/chain organizational structure is respectively filled into the pH three-layer skeleton. This is due to the fact that only BTC is powerful in cryptocurrency, while the rest are just knockoff coins built with physical blockchain technology, but without the backbone of PH technology.