Can you go backwards in a block chain? Can you go backwards in a block chain to unhash an old ledger and see the transaction details?
There seems to be a fundamental misunderstanding of how blockchains work. There is no hashing and hiding of transactions. Transactions are identified by their hashes and the hash is stored in a block, along with the transaction. There is no need for "unhashing" to see transaction details, the details are all there.