Secure rendering system that creates ray tracing samples with obfuscated positions, so that images can only be viewed by an authorized consumer able to recover the sample positions. Obfuscation of ray directions is integrated into the rendering process, for example by incorporating encryption into a lens shader. The rendering system never stores or transmits an image without obfuscating positions, so even the rendering system cannot see the image it is rendering. Embodiments may use public key cryptography, so that encryption of sample positions is done with a public key, and only the owner of the secret private key can view the rendered image. Since keys are asymmetric, the rendering system cannot decrypt the obfuscated samples. Piracy of rendered images is therefore mitigated. Some compositing operations may be performed on the secure rendering output prior to decrypting sample positions; for example, colors may be modified globally or for selected objects.