Handwriting identification needs to compare and review materials, and illiteracy has nothing to do with it.

Before the identification, there must be a reference that is confirmed to be an illiterate signature, or it can be written on the spot.

Then compare the writing habits and stroke characteristics of the contrast material and the test material (signature to be recognized). These things are habitual, untrained and hard to hide. Even if you feel that the two writings are different, even if you write in different calligraphy styles, it is hard to hide your feelings.