holy, i now know what's hash list, hash chain, hash tree, blockchain!
like this: file A, hash it, you get h(A). Now
blk1=h(A)+A.
blk2=h(blk1)+B.
blk3=h(blk2)+C.
etc. Each of A, B C etc are file or data.
This way, u can't fk the chain cuz can't reverse hash of hash of hash…