A method for encryption, decryption, or encryption and decryption of data in a crypto device having at least one crypto core may include: generating a tweak value corresponding to block data, which is placed at a random position from which the encryption, decryption, or encryption and decryption starts, from among sequential block data; and/or performing the encryption, decryption, or encryption and decryption from the block data using the tweak value. A method for encryption, decryption, or encryption and decryption of block data may include: generating a tweak value corresponding to the block data at a random position; and/or performing the encryption, decryption, or encryption and decryption of the block data using the tweak value.