A method is provided for creating an encrypted data file (700) from a data file having a sample entry box and a media data box. The sample entry box has description information therein. The media data box includes media data therein. The method includes: receiving the data file; encrypting the media data within the media data box with an encryption key; replacing the sample entry box with an encoded box (302); creating a sinf box (702) within the encoded box (302); creating a frma box (306) within the sinf box (702); and creating an schm box (704) within the sinf box (702). The schm box (704) indicates the type of formatting of the encrypted media data. The encoded box (302) does not include an initial counter that may be used to decrypt the encrypted media data.