Proofs of Space

Explore the concept of Proofs of Space in this 24-minute conference talk. Delve into the general idea behind this alternative to Proofs of Work, understanding its application in dealing with Sybil attacks. Examine how to measure computational difficulty and space usage, and learn about the advantages of Proofs of Space systems. Investigate the security definitions, efficiency metrics, and potential cheating strategies. Discover the main techniques used in constructing Proofs of Space schemes, including the use of Merkle trees for commitment. Gain insights into the proof phase and the results of implementing this concept. Finally, explore the application of Proofs of Space in Spacecoin and review related work in the field.

Intro
General idea
Proofs of Work - a tool for dealing with the Sybil attacks
How are the Pows used?
How to measure computational difficulty?
A drawback of PoW systems
What to do?
Example of an application
Main difference from Pows
Advantages
How to measure time and space
The proof is done with respect to an identifier Id
How to define security of a Pos
How to define the efficiency?
How to define soundness?
What would be the goal of a cheating prover?
Observation: a cheating prover has a simple (but inefficient) winning strategy.
Restrictions on cheating prover
Security definition
Why is constructing the Pos schemes non-trivial?
Our main technique
Very informally
How to build a Pos from a good graph?
Our solution: let the prover commit to R with a Merkle tree.
The Proof phase
Our results
Spacecoin
Previous/related/independent work