초록 ▼

A portable media player receives encrypted audio files and an encrypted content key from a central license server on the Internet. The media player supports digital rights management (DRM) by storing the encrypted audio file in its flash memory and disabling copying or playing of the audio file afte

A portable media player receives encrypted audio files and an encrypted content key from a central license server on the Internet. The media player supports digital rights management (DRM) by storing the encrypted audio file in its flash memory and disabling copying or playing of the audio file after a copy limit has been reached. The copy limit is a rule that is combined with the content key in a transfer key that can be encrypted together by the license server. The license server can detect cloning of the media player by reading a unique player ID from the player and detecting when too many accounts use the same unique player ID. The content key can be generated from polar coordinates of the unique player ID, player manufacturer, and song genre. A fingerprint sensor on the player can scan and compare the user's fingerprints to further detect cloning.

대표청구항 ▼

We claim: 1. A secure portable media player comprising: an input/output interface circuit for connecting to a host network connected to a license server and for receiving an encrypted media file downloaded from the license server to the secure portable media player; wherein the input/output interfa

We claim: 1. A secure portable media player comprising: an input/output interface circuit for connecting to a host network connected to a license server and for receiving an encrypted media file downloaded from the license server to the secure portable media player; wherein the input/output interface circuit also receives a transfer key from the license server, the transfer key including a content key and copy rules for the encrypted media file; a flash memory for storing the encrypted media file downloaded from the license server; a decryptor that receives the encrypted media file and uses the content key to generate a media stream of playable media; a media decoder for playing the media stream from the decryptor and generating an audio signal for generating audio heard by a user or generating a video display signal for generating a display visible to the user of the secure portable media player; and a processor for executing routines of instructions for activating the decryptor with the content key to unlock the media stream when copy rules for the encrypted media file have not been exceeded; a unique media player identifier, stored on the secure portable media player, that has a different value for each secure portable media player; wherein the input/output interface circuit transfers the unique media player identifier to the license server before receiving the encrypted media file downloaded from the license server to the secure portable media player, wherein the license server generates the content key as a function of polar coordinates of the unique media player identifier, a player manufacturer, and a song genre wherein the decryptor is disabled and prevented from generating the media stream when the copy rules have been exceeded, whereby copy rules are enforced by the secure portable media player. 2. The secure portable media player of claim 1 wherein the copy rules indicate when the encrypted media file is a copyrighted file, the copy rules also indicating a copy limit that indicates a number of times that the encrypted media file can be copied or can be played by the media decoder. 3. The secure portable media player of claim 2 further comprising: a play decrementor, activated to decrement a play count when the decryptor generates the media stream from an encrypted media file; a copy rule comparator that compares the play count from the play decrementor to the copy limit from the copy rules for the encrypted media file; and a play disabler that disables the decryptor and prevents generation of the media stream when the copy rule comparator indicates that the copy rules have been exceeded. 4. The secure portable media player of claim 3 further comprising: a fingerprint sensor on the secure portable media player for scanning a fingerprint of the user of the secure portable media player; a fingerprint comparator for comparing a current scan from the fingerprint sensor to a stored scan of a fingerprint in a security register; wherein the play disabler disables the decryptor and prevents generation of the media stream when the fingerprint comparator does not match the current scan to the stored scan, whereby fingerprint scanning secures the secure portable media player from use by an unauthorized user. 5. The secure portable media player of claim 2 wherein the flash memory stores encrypted media files and does not store the media stream generated by the decryptor, whereby decrypted media streams are not stored. 6. The secure portable media player of claim 2 further comprising: a key decryptor, receiving the transfer key from the input/output interface circuit, for generating the content key and the copy rules by decrypting the transfer key using an internal key; whereby the transfer key is encrypted. 7. The secure portable media player of claim 6 wherein the internal key is generated from a unique player identifier for the secure portable media player that is unique for each copy of the secure portable media player. 8. A digital rights management (DRM) system for a portable media player comprising: input/output interface circuit means for connecting to a host; processor means for executing instructions; memory means for storing an encrypted media file received by the input/output interface circuit means; decrypt means for decrypting the encrypted media file to generate playable media; decoder means for generating signals representing the playable media from the decrypt means; function key means for receiving inputs from a user to control operation of the processor means; display means for displaying control information to the user generated by the processor means; audio means, receiving the signals from the decoder means, for generating audible sounds to the user representing the playable media and encrypted in the encrypted media file; counter means for tracking a usage limit of the encrypted media file; disable means for disabling the decrypt means when the counter means indicates that the usage limit has been reached for the encrypted media file; host computer means, removably coupled to the input/output interface circuit means by a local bus, for connecting to a license server on a public network to download the encrypted media file from the license server; wherein the input/output interface circuit means transfers the unique media player identifier to the license server before receiving the encrypted media file downloaded from the license server to the portable media player; wherein the license server uses the unique media player identifier to generate the content key; wherein the license server generates the content key as a function of polar coordinates of the unique media player identifier, a player manufacturer, and a song genre whereby the unique media player identifier is sent to the license server to uniquely identify the portable media player before downloading and whereby usage of the encrypted media file is disabled when the usage limit is reached. 9. The DRM system for a portable media player of claim 8 further comprising: transfer key means, received over the input/output interface circuit means, for carrying the usage limit and a content key for the encrypted media file; wherein the content key is sent to the decrypt means for use as an encryption key to decrypt the encrypted media file to generate the playable media. 10. The DRM system for a portable media player of claim 9 further comprising: transfer-key decryption means for using a player key to decrypt the transfer key means received over the input/output interface circuit means to recover the usage limit and the content key. 11. The DRM system for a portable media player of claim 10 further comprising: further comprising: unique player identifier storage means for storing a unique media player identifier, wherein the unique media player identifier has a different value for each portable media player; wherein the player key is the unique media player identifier or is generated from the unique media player identifier. 12. The DRM system for a portable media player of claim 10 further comprising: host computer means, removably coupled to the input/output interface circuit means by a local bus, for connecting to a license server on a public network to download the encrypted media file from the license server; host computer identifier means for storing on the host computer means a unique host identifier, wherein the unique host identifier has a different value for each host computer means; and player key generator means, receiving the unique host identifier, for generating the player key as a function of the unique host identifier. 13. The DRM system for a portable media player of claim 12 further comprising: personal identifier means, in the host computer means, for generating a personal identifier from the unique host identifier; attachment means, in the host computer means, for attaching the personal identifier to a tag in the encrypted media file during downloading to the portable media player, whereby media files downloaded are tagged with the personal identifier generated by the host computer means. 14. The DRM system for a portable media player of claim 13 further comprising: personal identifier validate means, in the portable media player, for reading and validating the personal identifier tagged in the encrypted media file, and for activating the disable means when the personal identifier tag is not valid. 15. A method for managing digital rights on a portable media player comprising: sending a unique player identifier for the portable media player to a license server through a host computer; wherein the unique player identifier has a different value for each portable media player; receiving from the host computer an encrypted media file that was encrypted by the license server using a title key; receiving from the host computer an encrypted title key that is the title key encrypted by the license server using the unique player identifier; decrypting the encrypted title key on the portable media player using the unique player identifier of the portable media player to generate a recovered title key; decrypting the encrypted media file on the portable media player using the recovered title key to generate playable media; decoding the playable media to generate audio signals for generating audible sounds to a user of the portable media player; and detecting illegal cloning of the portable media player by: the license server generating the title key as a function of polar coordinates of the unique player identifier, a player manufacturer, and a song genre for a song in the encrypted media file; identifying a plurality of requests with a same polar coordinate, wherein the plurality of requests exceeds a threshold number of requests; disabling downloading of encrypted media files for the same polar coordinate when the plurality of requests exceeds the threshold number of requests; whereby cloning is detected by the same polar coordinate with requests exceeding the threshold number of requests. 16. The method of claim 15 further comprising: receiving on the host computer from the license server an encrypted copy rule that is a copy rule encrypted by the license server using a title key; wherein the copy rule indicates a number of allowed copies of the encrypted media file; decrypting the encrypted copy rule on the host computer using the unique player identifier to generate a recovered copy rule; adjusting a copy counter on the host computer for each copy of the encrypted media file downloaded to the portable media player or to another portable media player connected to the host computer; and comparing the copy counter to the recovered copy rule on the host computer and disabling downloading of the encrypted media file from the host computer to the portable media player when the recovered copy rule is violated.