It's absolutely unnecessary to break skin in order to track humans.
ID2020 Summit & Mission
September 2019, an annual summit was hosted by the ID2020 alliance, composed of significant partners from around the world. Microsoft, GAVI (Global Alliance of Vaccines and Immunizations), The Rockefeller Foundation, and a growing number of partners from international governments, universities, and humanitarian relief programs. The entire summit was sponsored by the UN Office of Information Communications Technology, the UN Refugee Agency, the International Telecommunication Union and the Danish Mission to the UN.
The mission of the ID2020 alliance is “Accelerating technology to ensure that everyone in need has access to a unique digital identity as part of their basic human right.”
So far, the system is mostly a proof of concept. But the researchers have already tried it out on rats and found that the patterns were still detectable nine months after injection.
In human cadaver skin models, the patterns outlasted five years of simulated Sun exposure.
"It's possible someday that this 'invisible' approach could create new possibilities for data storage, biosensing, and vaccine applications that could improve how medical care is provided, particularly in the developing world," MIT professor and senior author Robert Langer said in the statement.