Abstract: Systems and methods are disclosed for protecting a computer program from unauthorized analysis and modification. Obfuscation transformations can be applied to the computer program's local structure, control graph, and/or data structure to render the program more difficult to understand and/or modify. Tamper-resistance mechanisms can be incorporated into the computer program to detect attempts to tamper with the program's operation. Once an attempt to tamper with the computer program is detected, the computer program reports it to an external agent, ceases normal operation, and/or reverses any modifications made by the attempted tampering. The computer program can also be watermarked to facilitate identification of its owner. The obfuscation, tamper-resistance, and watermarking transformations can be applied to the computer program's source code, object code, or executable image.

Abstract: Systems and methods are disclosed for embedding information in software and/or other electronic content such that the information is difficult for an unauthorized party to detect, remove, insert, forge, and/or corrupt. The embedded information can be used to protect electronic content by identifying the content's source, thus enabling unauthorized copies or derivatives to be reliably traced, and thus facilitating effective legal recourse by the content owner. Systems and methods are also disclosed for protecting, detecting, removing, and decoding information embedded in electronic content, and for using the embedded information to protect software or other media from unauthorized analysis, attack, and/or modification.

Abstract: Systems and methods are provided for managing the transfer of electronic files. In one embodiment, a sender transfers an encrypted version of a file (such as a digitally encoded audio track, movie, document, or the like) to someone who wishes to receive it. The receiver computes a hash of the encrypted file, and sends it to a trusted third party. The trusted third party compares the hash that was computed by the receiver with another hash computed by the sender. If the two hashes match, the third party sends the file decryption key to the receiver. In some embodiments, the receiver may also send the third party payment information so that the sender, the content owner, and/or the third party can be paid for their role in the transaction. In a preferred embodiment, the payment information is only sent to, and/or used by, the third party once the third party has confirmed to the satisfaction of the receiver that the encrypted file in the receiver's possession will decrypt correctly.

Abstract: Software self-checking mechanisms are described for improving software tamper resistance and/or reliability. Redundant tests are performed to detect modifications to a program while it is running. Modifications are recorded or reported. Embodiments of the software self-checking mechanisms can be implemented such that they are relatively stealthy and robust, and so that it they are compatible with copy-specific static watermarking and other tamper-resistance techniques.