Time-Traveling Simulators Using Blockchains and Their Applications

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" summary

Defines a formal notion of time-traveling simulation where the simulator receives an F-block valid extension of the public chain and uses it to simulate interactions. Proves a concrete three-round zero-knowledge argument from injective one-way functions with a strict polynomial-time black-box time-traveling simulator, and a three-round two-party computation protocol from OWFs, PKE, signatures and 2-round OT. Soundness relies on a mining assumption (honest-majority and inability to convert short forks of length K into an F-length chain) and currently requires proof-of-work blockchains.

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" chapters (21)

1. 0:00Intro
2. 0:23Blockchains A public data-structure lediger
3. 2:16Simulation paradigm is central to Cryptography
4. 3:25Simulator is given more power
5. 6:49The blockchain data structure in more detail
6. 7:39How are new blocks generated?
7. 9:36Interactive Proofs
8. 11:11Different ZK notions and their philosophies Notion Philosophy
9. 12:13Defining Time-traveling ZK using Blockchains
10. 13:19Definition: Time-traveling ZK st: current state of the blockchain
11. 13:54How good is Time-traveling ZK?
12. 15:44Comparison with Super-poly Simulation
13. 17:25Comparison with ZK simulation in blockchain mode
14. 19:11Construction 1: Time-Traveling Zero Knowledge
15. 20:43Two Party Secure Computation (2PC)
16. 21:34Construction 2: Time-Traveling 2PC Theorem 2 Informat : Assume injective one way functions, public key encryption and signatures, and two round oblivious transfer There exists a three-round two-party secure computation protocol with a strict polynomial time black box time traveling simulator
17. 23:16Time-traveling Simulator for ZK
18. 23:51Soundness: Attempt 1
19. 24:58Soundness: Attempt 2 via Special Soundness of
20. 26:31Concluding Soundness Proof
21. 28:40Not covered in the talk

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