Wasabi Research Club #11 - Boltzmann (Bitcoin)
Channel: Wasabi Wallet
Date: 2020-03-17

Today our guests discuss various aspects of entropy and its relevance to Bitcoin transactions and privacy. They explore different interpretations and applications of entropy in relation to coin joints, transactions, and blockchain analysis. The conversation also touches on the challenges and validity of assumptions made in analyzing transactions, as well as the potential use of the Boltzmann protocol and the knapsack problem to improve entropy calculations. The section concludes with a discussion on the growth of privacy in Bitcoin transactions and the potential for future research.

Topic: Boltzmann (Bitcoin)

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00:00 Introduction

00:38 Weekly recap.

01:09 Flawed Coinjoins.

02:11 Joining transactions.

02:54 Anonymity in this framework.

04:26 Subset sum problem. / Bell number.

04:51 Entropy.

07:10 Laws of thermodynamics.

08:28 Shannon entropy.

13:00 Definitions: intrinsic entropy, actual entropy, max entropy, wallet efficiency, blockchain efficiency.

14:35 Results of computing entropy for 97 million transactions.

15:40 Discussion.

16:45 Number of sub-mappings.

18:06 Shannon entropy and information theory.

19:58 Pay-to-endpoint (P2EP) transactions.

21:09 Assumptions required to analyse transactions.

24:23 Heuristics across sub-mappings.

25:58 Correlation between input sums and output sums,

28:00 Knapsack. / input-input links, output-output links.

30:45 Utility of using Lg. / Bits of entropy. / Does privacy grow linearly? / Does anonymity grow exponentially.

37:07 Explanation of Lauren MT's results.

39:40 Meaning of entropy. / Binary questions. / How is entropy applied at scale or to Coinjoins?

41:22 3D Link probability matrix of a transaction. / Computational expense.

46:02 Next week's research.

48:40 Conclusion.