writes "Researchers at UC San Diego and Cornell University have developed software that they say can detect variations in flash behavior that are unique to each chip. The system uses 'physically unclonable functions' (PUFs), or variations in manufacturing that are unique to each element of each flash chip. Swanson described one PUF that his team has worked with, called Program Disturb. It uses a type of manufacturing flaw that doesn't affect normal operation but causes problems under test conditions."
Related: from last October, another description of such error-based identity assignment