Systems and methods for watermarking software and other media
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.
1. A method for watermarking computer code, the method performed by a computer system comprising a processor and a memory encoded with program instructions that, when executed by the processor, cause the system to perform the method, the method comprising:
inserting one or more encrypted marks into the computer code, each of the one or more encrypted marks being formed by
creating a copy of a mark,
combining extra information with the copy of the mark to create a modified mark,
encrypting the modified mark to create one of the one or more encrypted marks, and
combining the encrypted mark with plaintext information; and
wherein a recipient of the computer code decodes at least one of the one or more of the encrypted marks inserted into the computer code to create a set of decoded marks and
for each decoded mark in the set of decoded marks, the recipient identifies the extra information in the decoded mark; and
compares the extra information with the plaintext information.
2. A method as in claim 1 , wherein a plurality of encrypted marks are inserted into the computer code.
3. A method as in claim 2 , wherein each encrypted mark in the plurality of encrypted marks differs from any of the other encrypted marks in the plurality of encrypted marks.
4. A method as in claim 2 , wherein extra information combined with a copy of the mark differs from extra information combined with any other copy of the mark.
5. A method as in claim 1 , wherein at least one of the mark and the extra information includes a digital signature.
6. A method as in claim 5 , wherein the digital signature is a function, at least in part, of one or more of the mark and the extra information.