Thanks for playing! I spent a while reading up on super complicated signature recognition algorithms but in the end went for something much simpler.
For risk of pulling back the curtain, so I don't recommend reading this if you haven't played already, I generated heat maps of the signature, then to score I get the transform from the rect of the input to the rect of the heat map. Step one check it's not overly skewed, then score it based on points in the heat map. That does mean you're not scored on how much of the signature you miss, only what you hit. I got really into some of the papers on signature recognition, so who knows, I may revisit it after the Jam