Alok Menghrajani
Currently: security consulting and lecturer.
Previously: security engineering at Square Block. Co-author of Hack (the programming language) and put the 's' in https at Facebook Meta. Maker of various CTF puzzles.
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Seven cryptographers would like to exchange presents with each other. They are geographically located in different places, so they can't use a traditional white elephant scheme (everyone brings a wrapped gift and puts it on a table, people then draw names and take turn picking a gift).
Can you figure out a cryptographically equivalent scheme?
Specifically, design a distributed algorithm where:
- The algorithm results in every cryptographer knowing who they need to get a present for (they can tailor their presents) but not knowing who is getting them a present (there's a surprise factor).
- Each cryptographer has a public/private key pair.
- Each cryptographer knows the public key of the other six participants, as well as their address (so they can mail the presents).
___.-~"~-._ __....__
.' ` \ ~"~ ``-.
/` _ ) `\ `\
/` a) / | `\
:` / | \
<`-._|` .-. ( / . `;\\
`-. `--'_.'-.;\___/' . . | \\
_ /:--` | / / .' \\
("\ /`/ | ' ' / :`;
`\'\_/`/ .\ /`~`=-.: / ``
`._.' /`\ | `\ /(
/ /\ | `Y / \
jgs / / \ | | /`\ \
/ | | | | | | |
/___| /___| /___| /__|
'""" '""" '""" '"""
Happy holidays! I will post a solution here in a few weeks...