Breath print was a security method by which individuals were identified after giving a sample of their breath for analysis by a computer. Much like a fingerprint or handprint, a breath print was unique to each individual. This security method could be employed in order to access a secured area off limits to unauthorized personnel.
It was possible to defeat this security measure by obtaining a sample of an authorized person's saliva and blowing it into the sensor that detected the breath. In November of 2256, Michael Burnham accessed an engineering lab by obtaining a sample of her roommate Sylvia Tilly's saliva on a cloth and using a device to blow it onto the sensor.