A reproduction method capable of immediately revoking a leaked device key by dividing the device key into a first partial key and a second partial key is provided. The reproduction method includes the operations of receiving encrypted content to be reproduced, requesting a token for decrypting the received content from an external device containing a first partial key of a device via a network, receiving the requested token from the external device, and decrypting the received token by using a second partial key contained in the device, thereby preventing content encrypted and distributed before revocation of an illegally copied device from being reproduced, and minimizing damage due to key leakage.