Because of the image file can be accessed and restored by anybody, so in order to protect your data from unauthorized access, you could encrypt it by setting a password. Enter your password in the password field to encrypt it, and allows at most 63 characters.
Note: If you try to recover data from a password-protected archive, the program will ask for the password in a special window, allowing access only to authorized users. The program use strong industry-standard AES (Advanced Encryption Standard) cryptographic algorithm, it will totally encrypt all data in the image.