If I had to fingerprint an image, like give an image a unique identity. Image being a picture of any object. What techniques can I use. Given an imitation of the image I need to say that it is not the original. But bottomline is to fingerprint an object. How do I do so... I'm thinking of keypoint detection methods like delf, superpoint, and silk. What do you guys think

Please share your ideas. I'm a beginner so I could use all your help