Methods and systems are provided for cryptographically protecting secure content in connection with a graphics subsystem of a computing device. Techniques are implemented to encrypt the contents of video memory so that unauthorized software cannot gain meaningful access to it, thereby maintaining confidentiality. Moreover, a mechanism for tamper detection is provided so that there is awareness when data has been altered in some fashion, thereby maintaining integrity. In various embodiments, the contents of overlay surfaces and/or command buffers are encrypted, and/or the GPU is able to operate on encrypted content while preventing its availability to untrusted parties, devices or software.