Real World Crypto 2021 - Session 11: Cryptocurrency


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Session video

Omer Schlomovits (ZenGo) / Attacking Threshold Wallets / video slides

Threshold wallets are based on Threshold Signing, an application of MPC. In threshold signing:

Attack 1: “Forget and Forgive”

Attack 2:" Golden Shoe"

Christian Badertscher/Philipp Kant (IOHK/Cardano) / From Crypto-Paper to Crypto-Currency: the Cardano Consensus Layer / video slides

IOHK have a rather pretty website involving interactive fractal graphics!

At the heart of Cardano is Ouroboros, the algorithm that underpins the Ada cryptocurrency.

Protocol execution model for distributed computation over a network:

If your security model has captured all properties then security proofs should be meaningful in practice.

?? Ouroboros: Nakamoto-style proof-of-stake blockchain protocol realizing a ledger
(since 2017) Has gone through 6 iterations of improvement, switching between experiences gained in implementation, and returning to theory to address findings

?? Property-based testing. Once properties are described, random inputs generated, and test that desired properties still hold. If they don’t you drill down through the inputs until you isolate the problem with some specific inputs

Risk of system collapse or takeover when transitioning from a small scale test sytem to a much more decentralised one! Need to do this gradually.

Bernardo David (ITU Copenhagen) / Alice in Randomland: How to Build and Use Distributed Randomness Beacons / paper video

What is a randomness beacon?

What are their important parameters?

Construction 1: Publicly Verifiable Sercret Sharing (PVSS)

Construction 2: Verifiable Random Function

Construction 3: Threshold VRFs

Construction 4: Time-based primitives

These could be combined, e.g. using C1 to reseed C3