Ask Slashdot: Why Haven’t We Implemented Public Key Infrastructure Voting?

Long-time Slashdot reader t0qer has a question: why haven’t we gone to an open source, Public Key Infrastructure-based voting system? “I’m fairly well versed in PKI technology, and quoting this site, it would take traditional computers 300 trillion years to break RSA-2048 for a single vote.”
SSL.com has a pretty interesting piece on using Public Key Infrastructure in voting. There’s also a GitHub project that leverages PKI and IBM blockchain technology… It just seems like paper at this point has outlived its secureness. A closed sourced voting system doesn’t really seem like the kind of thing Slashdot would really get behind. SSL’s article points out that the technology seems to exist already. Nearly half the population of Estonia already votes online, and four U.S. states (Arizona, Colorado, Missouri and North Dakota) already have web portals that allow for absentee voting. (And West Virginia has a mobile voting app that uses blockchain technology.) [L]uckily, the groundwork for securing the practice of remote, online voting is already there. We have been conducting many delicate transactions online for some time — the secure transfer of information has been a cornerstone for many industries that have successfully shifted online such as personal banking and investing, and those methods of securing and authenticating information can be employed in voting as well. For years, people have suggested that the use of blockchain technology could be used to secure elections and increase voter turnout. Share your own thoughts in the comments. Why haven’t we implemented Public Key Infrastructure voting?