so, fingerprints access:

"For a fake fingertip, however, you need jelly stiff like gummi candy. I used a one-to-one mix of water and gelatine, weight for weight."

LET'S SIMPLIFLY:

Everybody knows the fingerprints cand be stolen out of androids and laptops....so, here the scheme would be glue the gelatine to the scanner, and then tape it to the fake finger

read at:
http://www.puttyworld.com/thinputdeffi.html