A portion of a digital good is selected to be used as a substitution box (S-box) in encrypting at least another portion of a digital good. The digital good being encrypted can be the same digital good, or alternatively a different digital good, than the digital good from which the portion used as an S-box is obtained. During the encryption process, the S-box is used to substitute values of the portion being encrypted with new values (a process also referred to as "scrambling").