Where "universal" stands for "The trait must be owned by any person (except for rare exceptions ...)"?
(Notice: this is a question related to biometric systems, hopefully this is the right stackexchange site).
Where "universal" stands for "The trait must be owned by any person (except for rare exceptions ...)"?
(Notice: this is a question related to biometric systems, hopefully this is the right stackexchange site).
This is absolutely not my area, but I think the answer is no.
It isn't universal because not everyone can write (illiteracy, blindness, missing limbs, spring to mind) - see https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/118600/applicants-unable-to-write.pdf .
I would assume that if there exist provisions for delivering a passport without the need for a signature (thumbprints are one option, but assume that the person has a thumb - the absence of one might be part of the reason the same person cannot write), then it isn't universal.
I also suspect that inability to write might in fact be common enough it can't be considered an edge case - the worldwide literacy rate is apparently around 86% (https://en.wikipedia.org/wiki/List_of_countries_by_literacy_rate).