Which characteristic is NOT found in a valid identification document?

A valid identification document typically contains several key characteristics that help verify the identity of the individual. Among these, a signature of the holder serves as a personal verification, allowing comparison with the individual's signature during transactions. A photograph of the holder is crucial for visual identification, ensuring that the person presenting the document matches the identity indicated. An official seal from a governmental office lends authority and authenticity to the document, confirming that it has been properly issued.

In contrast, a Social Security number is not considered a core characteristic of valid identification documents. While it may be present on some forms of ID, it is not universally required and does not serve the same purpose as the other characteristics. It is primarily used for tracking purposes in benefits and taxation rather than for immediate visual identification, making it less critical for validating identity in general identification contexts. Thus, the absence of a Social Security number does not invalidate a document, as the other elements listed are far more essential for proving identity.