Project contains implementations of following protocols used to solve the dining cryptographers problem:
| Protocol | Paper | Authors |
|---|---|---|
| DC-Net | The Dining Cryptographers Problem: Unconditional Sender and Recipient Untraceability | David Chaum |
| [In progress] AV-Net | A 2-Round Anonymous Veto Protocol | Feng Hao, Piotr Zielinski |
The problem these protocols solve is how to send a bit of information to other participants of the protocol anonymously, or, rephrased, how to find out whether anyone in a group has vetoed without getting to know his identity.
In DC-Net there are 3 main security problems:
- Collisions - if two protocol participants vetoed, they veto would cancel out
- Without proofs/commitments to broadcasts, participants can change them to mess with protocol
- Cost of setup - protocol requires that every participant has shared key with every other participant
AV-Nets solves them:
- Chance for collision is negligible, intentional collisions are as hard to do as DDH
- Proofs of secrets are required
- Setup time is linear, it involves a single exponentiation from every participant
AV-Net implementation still does not have built in zero knowledge proofs. They shall follow
AV-Net implementation uses 2 cryptographic primitives:
- Zero knowledge proofs for making sure that participants can not change their vote after gaining knowledge of other peoples vote, it should be non interactive and might follow algorithm below:
- P wants to proof he knows x where y = g^x
- P picks a random v and computes t = g^v and keeps it as first term of the proof
- P computes c = H(g,y,t)
- P computes r = v - cx and keeps it as second term of the proof
- V checks t = g^r * y^H(g,y,t)
- DDH problem hardness to make sure that last participant of protocol can not change a non-1 result into 1
https://crypto.stackexchange.com/questions/24063/zero-knowledge-non-interactive-proof-with-random-oracle https://en.wikipedia.org/wiki/Dining_cryptographers_problem http://homepages.cs.ncl.ac.uk/feng.hao/files/av_net.pdf http://www.cs.cornell.edu/People/egs/herbivore/dcnets.html