Abstract: A hybrid traitor-tracing enabling system comprises an inner code and a multi-level outer code. The inner code comprises encrypted tables comprising codewords for file segment variations. One level of the multi-level outer code comprises assignments of a cluster of sequence keys to manufacturers or models of media players. Another level comprises assignments to the media players of sequence keys within the cluster. The system enables tracing of only a manufacturer or model, or a manufacturer, model, and a media player. When tracing a manufacturer or model, the system enables detection with relatively few recovered files. With additional recovered files, the media player used for piracy can be discovered. Furthermore, the present system enables detection of collusion between manufacturers or models and collusion between individual media players.

Abstract: A system and method is disclosed for performing unified broadcast encryption and traitor tracing for digital content. In one embodiment a media key tree is divided into S subtrees, the media key tree including media keys and initial values, which may be random values. The digital content is divided into a plurality of segments and at least some of the segments are converted into a plurality of variations. The random values are transformed into media key variations and a separate media key variant is assigned to each of the subdivided subtrees. A unified media key block including the media key tree is stored on the media.

Abstract: A system and method is disclosed for performing unified broadcast encryption and traitor tracing for digital content. In one embodiment a media key tree is divided into S subtrees, the media key tree including media keys and initial values, which may be random values. The digital content is divided into a plurality of segments and at least some of the segments are converted into a plurality of variations. The random values are transformed into media key variations and a separate media key variant is assigned to each of the subdivided subtrees. A unified media key block including the media key tree is stored on the media.

Abstract: A method for enforcing compliance in both the copy protect domain and service subscription domain for streamed multicast data. Each content is encrypted with a title key that itself is encrypted with a channel unique key which is a hash of a session key and a channel key. A compliant player is given the channel key upon registration for a subscription service (representing subscription protection) and is also given device keys upon activation (representing copy protection) for decrypting the session key. Consequently, the channel unique key can be obtained (and, hence, the content decrypted) only by a player that is compliant with both copy protection rules and subscription rules. The channel key can be refreshed periodically as subscriptions change or expire.

Abstract: A method for disabling a traitor receiver in a broadcast encryption system includes examining augmentations of at least one redistributed version of a file in a group of files, wherein each authorized receiver acquired decryption keys only for the particular augmentations that it used. A level to which the augmentations correspond to a first set of super codes previously assigned to each authorized receiver is determined. A conclusion is drawn regarding the number of receivers that are traitor receivers. The receivers concluded to be traitor are selectively revoked. The process is repeated by selecting another set of super codes; selected to reduce the number of authorized receivers concluded to be traitor receivers. The sets of super codes are selected such that the number is made larger to achieve quicker revocation of a traitor receiver at the cost of increasing chance of an incorrect revocation of an innocent receiver.

Abstract: A title key protection system includes a title key with recordable media content; storage in a repository is not required. The title key is decrypted when needed by a clearinghouse, and then re-encrypted. The title key confers rights from the content owners to the user to play and copy the content for personal use. A user downloads encrypted content from a content repository. The user's media recording device extracts an encrypted title key from the content and obtains a media key block and media ID from the physical media on which the content will be recorded. The encrypted title key, media key block, and media ID are transmitted to a clearinghouse. The clearinghouse decrypts the title key and derives a media unique key from the media key block and media ID. The clearinghouse re-encrypts the title key with the media unique key and returns this re-encrypted title key to the media recording device for recording with the content on the physical media.

Abstract: A system, method, and computer program product for preventing a malicious user from analyzing and modifying software content. The one-way functions used in prior art systems using dynamically evolving audit logs or self-modifying applications are replaced with a one-way function based on group theory. With this modification, untampered key evolution will occur inside a defined mathematical group such that all valid key values form a subgroup. However, if the program is altered, the key will evolve incorrectly and will no longer be a member of the subgroup. Once the key value is outside of the subgroup, it is not possible to return it to the subgroup. The present invention provides a limited total number of valid keys. The key evolution points are not restricted to locations along the deterministic path, so the key can be used in various novel ways to regulate the program's behavior, including in non-deterministic execution paths.

Abstract: A system and method is provided for identifying the source of an unauthorized copy of content. The method includes embedding a unique user fingerprint code to into each of a plurality of authorized copies of content and identifying an unknown fingerprint code in an unauthorized copy of the content. Each member of the unknown fingerprint code is compared to each corresponding member in each of the user fingerprint codes. A score is assigned to each of the user fingerprint codes based on the comparison and users associated with scores exceeding a threshold are identified as a source of the unauthorized copy.

Abstract: A system and method is provided for identifying the source of an unauthorized copy of content. The method includes embedding a unique user fingerprint code to into each of a plurality of authorized copies of content and identifying an unknown fingerprint code in an unauthorized copy of the content. Each member of the unknown fingerprint code is compared to each corresponding member in each of the user fingerprint codes. A score is assigned to each of the user fingerprint codes based on the comparison and users associated with scores exceeding a threshold are identified as a source of the unauthorized copy.

Abstract: A unified broadcast encryption system divides a media key tree into S subtrees, divides digital content into segments, and converts some of the segments into variations; the number of segments and variations is q. The system subdivides each of the subtrees into q/|S| subdivided subtrees, assigns a key media variant to each of the subdivided subtrees, and generates a unified media key block (MKBu). The system decrypts digital content by obtaining required key media variants from the MKBu, using the key media variant to find an entry in a variant key table, decrypt a title key, and locate a variant number from the variant key table. The system uses the variant number to identify which of the variations may be decrypted by the title key and uses the title key to decrypt segments and variations.

Abstract: A tree is used to partition stateless receivers in a broadcast content encryption system into subsets. Two different methods of partitioning are disclosed. When a set of revoked receivers is identified, the revoked receivers define a relatively small cover of the non-revoked receivers by disjoint subsets. Subset keys associated with the subsets are then used to encrypt a session key that in turn is used to encrypt the broadcast content. Only non-revoked receivers can decrypt the session key and, hence, the content.

Abstract: A system and method for enabling broadcast programs to be copied once only by consumer recorders includes writing a unique media identification on each blank disk to which content is to copied in a read-only area of the disk before it is initially recorded. Also, a one-way key management media key block is written to the disk. A content key is derived by combining a media key, derived from the media key block, with the media identification. Additionally, to facilitate copying the content one time only, an exchange key is established between the recorder and a sender such as a satellite receiver or a disk player that is associated with the recorder, and the exchange key is modified with one or more special numbers representing control commands including copy once and copy no more. The modified exchange key is then encrypted using the content key to render an encrypted modified exchange key, and the encrypted modified exchange key is then hashed with a nonce to render a bus content key.

Abstract: A system, method, and computer program product for preventing a malicious user from analyzing and modifying software content. The one-way functions used in prior art systems using dynamically evolving audit logs or self-modifying applications are replaced with a one-way function based on group theory. With this modification, untampered key evolution will occur inside a defined mathematical group such that all valid key values form a subgroup. However, if the program is altered, the key will evolve incorrectly and will no longer be a member of the subgroup. Once the key value is outside of the subgroup, it is not possible to return it to the subgroup. The present invention provides a limited total number of valid keys. The key evolution points are not restricted to locations along the deterministic path, so the key can be used in various novel ways to regulate the program's behavior, including in non-deterministic execution paths.

Abstract: A traitor tracing system generates a hypothesized model of the circumvention device that models a hypothesized set of device keys compromised by the circumvention device. The system iteratively invokes a subset tracing system to identify a compromised device key until substantially all the compromised device keys in the set of compromised device keys are identified so as to disable the circumvention device. A subset tracing system generates a circumvention device model that models behavior of a circumvention device using prior knowledge and The system iteratively selects and applies to the circumvention device a test based on the hypothesized model and the circumvention device model and receives a response from the circumvention device indicating a success of the test in playing protected content on the circumvention device.

Abstract: A system and method for enabling broadcast programs to be copied once only by consumer recorders includes writing a unique media identification on each blank disk to which content is to copied in a read-only area of the disk before it is initially recorded. Also, a one-way key management media key block is written to the disk. A content key is derived by combining a media key, derived from the media key block, with the media identification. Additionally, to facilitate copying the content one time only, an exchange key is established between the recorder and a sender such as a satellite receiver or a disk player that is associated with the recorder, and the exchange key is modified with one or more special numbers representing control commands including copy once and copy no more. The modified exchange key is then encrypted using the content key to render an encrypted modified exchange key, and the encrypted modified exchange key is then hashed with a nonce to render a bus content key.

Abstract: A cryptographic authentication system comprises an authentication media key block that comprises media key precursors. The system generates transformed keys by applying a function to a media ID of a media and each of the media key precursors, and generates entries in a binding table by applying an encrypting function to a media key of an encrypted content and each of the transformed keys. To play encrypted content, a media player processes the authentication media key block using a device key to extract a media key precursor, extracts a media key from the binding table using the extracted media key precursor and the media ID, and verifies that the extracted media key matches the media key of the encrypted content, allowing the media device to decrypt and play the encrypted content.

Abstract: Software intrusion is proactively detected using a dynamically evolving audit log wherein log entries are generated in the audit log and key values are evolved based upon a one-way function depending on both the previous log entry and the previous key. The audit log with the generated log entries and the final key value is transmitted to a clearinghouse that detects software intrusion by analyzing these values. In an effort to reduce the size of the log to be transmitted, the log entries are assigned identical values, thereby only needing to transmit one log entry and the last key value to the clearinghouse.

Abstract: A system, method, and computer program product enabling individual user devices to authenticate and validate a digital message sent by a distribution center, without requiring transmissions to the distribution center. The center transmits the message with an appended modulus that is the product of two specially selected primes. The transmission also includes an appended authentication value that is based on an original message hash value, a new message hash value, and the modulus. The new message hash value is designed to be the center's public RSA key; a corresponding private RSA key is also computed. Individual user devices combine a digital signet, a public modulus, preferably unique hardware-based numbers, and an original message hash to compute a unique integrity value K. Subsequent messages are similarly processed to determine new integrity values K?, which equal K if and only if new messages originated from the center and have not been corrupted.

Abstract: A system and method for enabling authorized music from a CD or DVD to be compressed by a user for the user's own use, but to prevent the recompression of unauthorized music from, e.g., the Internet, includes hashing the music during recording with a cryptographic hash, and then signing the hash with a digital signature derived from the hash. Subsequent unauthorized compression and recompression will destroy the digital signature. Accordingly, music to be recorded is hashed to obtain a test digital signature and if, after hashing, the test digital signature matches the digital signature accompanying the music, compression and recording are allowed to proceed.

Abstract: Enhanced multimedia content on physical media interacts with the user through a media player and the Internet. Enhanced multimedia utilizes IDs for pieces of content on the media and a media key block. On the enhanced media is a file with a list of URLs. As the enhanced media plays a title requiring an external permission for decryption, the media player accesses the URL for that title and obtains the permission. The permission may be purchased or provided for free. Secure encryption and transmission of permission is accomplished by broadcast encryption using a media key block. Each media has a unique set of keys that allow the media player to process the media key block; however, each media follows a unique path through the media key block. All legitimate media players obtain the media key; circumvention devices cannot decipher the media key block.