  Printing custom DNA sequences is essential to scientific and biomedical
research, but the technology can be used to manufacture plagues as well as
cures. Just as ink printers recognize and reject attempts to counterfeit money,
DNA synthesizers and assemblers should deny unauthorized requests to make viral
DNA that could be used to ignite a pandemic. There are three complications.
First, we don't need to quickly update printers to deal with newly discovered
currencies, whereas we regularly learn of new viruses and other biological
threats. Second, anti-counterfeiting specifications on a local printer can't be
extracted and misused by malicious actors, unlike information on biological
threats. Finally, any screening must keep the inspected DNA sequences private,
as they may constitute valuable trade secrets. Here we describe SecureDNA, a
free, privacy-preserving, and fully automated system capable of verifiably
screening all DNA synthesis orders of 30+ base pairs against an up-to-date
database of hazards, and its operational performance and specificity when
applied to 67 million base pairs of DNA synthesized by providers in the United
States, Europe, and China.
