Tamper-proof sofware

Anti-tamper software (or tamper-resistant software) is software which makes it harder for an attacker to modify it. The measures involved can be passive such as obfuscation to make reverse engineering difficult or active tamper-detection techniques which aim to make a program malfunction or not operate at all if modified.[1]
There are no provably secure software anti-tampering methods, thus the field is an arms race between attackers and software anti-tampering technologies.[2]