Which hash function did you use? You cannot use a cryptographic secure hash function to calculate a distance between data. If this were possible you could use

Which hash function did you use? You cannot use a cryptographic secure hash function to calculate a distance between data. If this were possible you could use a gradient descent like algorithm to find pre images. (I.e. the whole hash changes if you change one bit in the input) And when I tested it, it looked like the symbol was completely random. (As it should be) Edit: It's called the avalanche effect http://en.wikipedia.org/wiki/Avalanche_effect http://en.wikipedia.org/wiki/Avalanche_effect