A method of producing a stream of digital data. The method includes determining a plurality of portions within the stream of digital data, such that a portion of the stream of digital data is encrypted with an encryption key that is capable of being decrypted by a decryption key and the portion including therein another decryption key capable of decrypting a subsequent portion of the stream of digital data, and the subsequent portion of the stream of digital data is encrypted with another encryption key that is capable of being decrypted by the another decryption key. The method also includes transmitting the stream of digital data, including the portion and the subsequent portion.