A tamper-proof software watermark using code-based encryption

Utilizing a modified PPCT structure, a tamper-proof software watermark solution with code-based encryption was proposed. The general Chinese remainder theorem was exploited to split the watermark which was represented as a big number into pieces to enhance stealthiness. Changes to the source and object code were made to embed the watermark, and according to certain policies some parts of the object code was encrypted with an en/decryption key that was highly coupled with the object code to increase robustness and tamper-proof capability.