1. A method of creating an image hash, comprising: identifying features at different locations within a sample image; identifying descriptor vectors for at least a subset of the features, the subset defining key points of the image, the descriptor vectors describing local image information around the key points, where each descriptor vector is an n-dimensional array and is represented as a unary feature of dimension 128×128; and generating key points based on hashes of data vectors that include at least one of the descriptors, where each feature is a 36×20 hash value.