Tampering with the last block In a blockchain, considering that each block stores the hash of the previous block, the hash of the last block is not stored anywhere. How is this block tamperproof?
The hash that identifies a block is calculated from the block header. This hash must fulfil the difficulty requirements. Every node will check any block that they receive for validity. Since it requires a lot of proof of work to create a block whose hash fulfils the difficulty statement, it's infeasible to fake blocks and trivial to verify valid blocks.