Method for conditional decoding content and apparatus therefor

A conditional decoding method of contents and an apparatus thereof are provided to control an access for contents as a content unit by determining whether a contents key is revoked and selectively decoding the encoded contents using the contents key based on the determination result. A conditional decoding method of contents includes the steps of: receiving at least one of the contents key check data for checking a set of unrevoked contents key or the revocation of the contents key(310); determining whether a contents key for encoding and/or decoding the contents is revoked(320); selectively decoding the encoded contents using the contents key based on the determination result(330). The step of determining the revocation of the contents key includes the step of determining whether the contents key is revoked based on the inclusion state of the contents key for a set of the unrevoked contents.