Hash pointers are an important component of blockchain security. A "genesis block" is the first block in a chain. Following this basic block, the subsequent blocks use hash pointers to refer back to previous blocks. Individual blocks are linked together using hash pointers. The hash of all of the data in the block before it is stored in hash pointers. If an effort is made to change prior data, the hash of the updated data will no longer be appropriately matched to the pointers in follothe wing blocks. This increases blockchain security by making past data immutable and tamper-evident.