The IACR Can't Decrypt with Matt Bernhard
Cybersecurity

Security Cryptography Whatever

The IACR Can't Decrypt with Matt Bernhard

Security Cryptography Whatever•Dec 31, 2025

AI Summary

The episode examines the IACR's botched Helios election, where a key management failure forced the organization to discard the vote and schedule a new election. Guest Matt Bernhard, an expert in secure voting systems, explains how Helios' homomorphic encryption works, why proper key handling is critical, and what design pitfalls led to the failure. The hosts discuss broader implications for cryptographic voting protocols and highlight alternative systems like ElectionGuard that aim to avoid similar issues.

Episode Description

The International Association of Cryptologic Research held their regular election using secure voting software called Helios…and lost the keys to decrypt the results, leaving them with no choice but to throw out the vote and call a new election. Hilarity ensues. We welcome special guest Matt Bernhard who actually works on secure voting systems to explain which bits are homomorphically additive or not.

Watch on YouTube: https://www.youtube.com/watch?v=euw_yqAQFI8

Transcript: https://securitycryptographywhatever.com/2025/12/30/iacr-helios

Links:

  • NYT: https://www.nytimes.com/2025/11/21/world/cryptography-group-lost-election-results.html

  • IACR Memo: https://www.iacr.org/news/item/27138

  • https://www.iacr.org/elections/

  • https://vote.heliosvoting.org/faq

  • https://github.com/Election-Tech-Initiative/electionguard

  • https://www.usenix.org/legacy/events/sec08/tech/full_papers/adida/adida.pdf

  • https://www.iacr.org/elections/eVoting/about-helios.html

  • https://www.iacr.org/elections/eVoting/

  • https://crypto.ethz.ch/publications/files/CrGeSc97b.pdf

  • https://electionguard.vote/

  • https://eprint.iacr.org/2025/1901

  • https://freeandfair.us/blog/open-free-election-technology/

  • https://www.starvoting.org/

  • https://mbernhard.com/

"Security Cryptography Whatever" is hosted by Deirdre Connolly (@durumcrustulum), Thomas Ptacek (@tqbf), and David Adrian (@davidcadrian)

Show Notes

The International Association of Cryptologic Research held their regular election using secure voting software called Helios…and lost the keys to decrypt the results, leaving them with no choice but to throw out the vote and call a new election. Hilarity ensues. We welcome special guest Matt Bernhard who actually works on secure voting systems to explain which bits are homomorphically additive or not.

Watch on YouTube: https://www.youtube.com/watch?v=euw_yqAQFI8

Transcript: https://securitycryptographywhatever.com/2025/12/30/iacr-helios

Links:

- NYT: https://www.nytimes.com/2025/11/21/world/cryptography-group-lost-election-results.html

- IACR Memo: https://www.iacr.org/news/item/27138

- https://www.iacr.org/elections/

- https://vote.heliosvoting.org/faq

- https://github.com/Election-Tech-Initiative/electionguard

- https://www.usenix.org/legacy/events/sec08/tech/full_papers/adida/adida.pdf

- https://www.iacr.org/elections/eVoting/about-helios.html

- https://www.iacr.org/elections/eVoting/

- https://crypto.ethz.ch/publications/files/CrGeSc97b.pdf

- https://electionguard.vote/

- https://eprint.iacr.org/2025/1901

- https://freeandfair.us/blog/open-free-election-technology/

- https://www.starvoting.org/

- https://mbernhard.com/

"Security Cryptography Whatever" is hosted by Deirdre Connolly (@durumcrustulum), Thomas Ptacek (@tqbf), and David Adrian (@davidcadrian)

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