A device and method of applying a parity to encrypt data for protection is disclosed. A parity generator generates a parity bit in accordance with a data to be outputted. A first parity location generator generates an inserting position N for the parity bit in accordance with a predetermined algorithm. A parity-inserting unit inserts the parity bit in a position between (N-1)th- and Nth-bit of the data in accordance with the inserting position N, thereby generating an encrypted data.