The safest way to return to full-capacity mass gatherings is to make sure attendees have been vaccinated. The right software could help, but there are some privacy and equity concerns. On today's show, New York recently launched a vaccine passport called the "Excelsior Pass." Brian Behlendorf, general manager of Blockchain Healthcare and Identity at the Linux Foundation of Public Health, talks about what it is, and how people in the open source community are advocating for systems like these to be linked, so people don't need multiple apps. Then, Albert Fox Cahn, founder and executive director of the Surveillance Technology Oversight Project (STOP) at the Urban Justice Center, a New York–based civil rights and privacy group, and a fellow at the Engelberg Center for Innovation Law & Policy at NYU School of Law shares concerns about privacy and the digital divide.