Arnold Encryption Algorithm Based on PN Sequence

Arnold Cat transformation is a classical algorithm of image scrambling.But its periodicity restrains the times of image scrambling,so the number of the keys is not enough.This paper presented a modified Arnold method,which uses PN sequence and secure hash algorithm to generate a random parameter sequence,then divides an image into 4 pieces and carries out Arnold algorithm to the 4 pieces respectively.The Arnold algorithm effectively increases the number of the keys,and overcomes the attack via the exhaustive analysis,which enhances the security.