A data recording/reproducing method wherein encrypted digital data obtained by subjecting digital data to first encrypting by using a contents key and encrypted contents key obtained by subjecting the contents key to second encrypting are recorded on a recording medium, the encrypted digital data and the encrypted contents key, having been recorded, are reproduced, and the encrypted digital data is decrypted by using the contents key obtained by decrypting the encrypted contents key, thereby to obtain the digital data.

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