It depends what you mean by that.
The block hash is the hash of ordered blocks and their ordered transactions up to the block height.
If you want to easily prove something outside what is already provided then you might have to consume the chain and organize appropriately.
Hope it helps.
It is possible to rewrite blockchain history and replace a transaction by another one. To do so you have to replace already mined blocks by new ones and this new "fork" has to have a larger proof of work.
Your need to have more computation power than the honest miners. This attack is called a 51% attack.
The pool manager is in charge of validating transactions and building a candidate block for the pool miners :
Most mining pools are "managed," meaning that there is a company or individual running a pool server. The owner of the pool server is called the pool operator, and he charges pool miners a percentage fee of the earnings.
The pool server ...