Transaction Input/Output Sorting

The email exchange discusses the difficulty in detecting wallet boundaries in bitcoin transactions. Currently, it is possible to determine if a transaction uses bip69 or not and wallets are generally consistent in their use of bip69. This makes it easier to detect change in a transaction by looking at factors such as the amount of significant digits and how outputs are spent. However, an outside observer cannot tell if a transaction uses deterministic sorting or not, making it harder to establish wallet boundaries. The author expresses concern about the fungibility of bitcoin due to the effectiveness of blockchain analysis and the widespread use of centralized analytics services. They believe that unidentified bitcoin may soon be flagged as suspicious, potentially harming its value determined by its history. The author also notes that although blockchain analysis can be accurate, it relies heavily on fragile heuristics and can be easily tricked.