A data encryption device for storage medium has an encryption key input interface for acquiring a user encryption key; a block code encoder for encoding and decoding data; a scrambler connected with the encryption key input interface and the block code encoder to scramble and descramble data according to the user encryption keys respectively inputted; and a controller connected with the block code encoder and the scrambler, performing an encryption process transmit original data to the block code encoder for encoding, the encoded data to the scrambler for scrambling, and the scrambled data to a storage medium for storage, and performing a decryption process to transmit the scrambled data to the scrambler for descrambling, the encoded data to the block code encoder for decoding to acquire the original data when the user encryption keys respectively inputted in the encryption process and the decryption process are identical.