> whose hash codes are crypographically (slowly) calculated That's a rather clumsy way of saying that blockchains have Proof of Work. In combination with the L

> whose hash codes are crypographically (slowly) calculated That's a rather clumsy way of saying that blockchains have Proof of Work. In combination with the Longest Chain Rule (which actually means heaviest rather than longest) this make the cost of changing history extremely high.