From the legal eagles at The Volokh Conspiracy, December 13:
Attorney-Eyes-Only Disclosure of Heuristics Used by Government in Analyzing Blockchain Transactions
From Thursday's decision by Judge Randolph Moss (D.D.C.) in U.S. v. Sterlingov, which holds that defendant Roman Sterlingov should be barred from "personally reviewing" "the sensitive, supplemental heuristic information that was created by the government's expert (for the benefit of the defense) and provided to the defense in September 2023," which is to say that only his lawyers should have access to it:
Here, good cause exists for limiting access to the sensitive, supplemental heuristic material in the manner that the government proposes. As government counsel persuasively explained at the November 13, 2023 hearing, the material at issue is neither evidence against the defendant nor is it exculpatory evidence. Instead, the information is best understood as a supplemental expert disclosure. It was provided to the defense, at the Court's urging, to ensure that the defense was fully apprised of the heuristics used in Chainalysis's Reactor software, which the government's experts, Luke Scholl and Elizabeth Bisbee, used to cluster certain blockchain transactions at issue in the case. This supplemental expert disclosure did not exist at the time either of the government experts prepared their reports, and the government itself came into possession of the material from Chainalysis only as an intermediary, before passing it along to defense counsel.
The government also explained that the sensitive, supplemental heuristic information provides a more granular account of the behavioral heuristics that Reactor employs than the account previously disclosed to Sterlingov, defense counsel, and an array of defense experts in Bisbee's expert report and appendices. That additional detail includes "exactly how" specific behavioral heuristics are "implemented and weighed," and, significantly, it "includes information about the kickouts"—that is, "what behavior would cause Chainalysis not to cluster" a given address. Armed with this information, those bent on preventing the government (or its expert) from clustering addresses, and thereby identifying their owners and connecting them to potentially illicit transactions, could readily adjust their conduct to evade detection.
By way of analogy, consider criminal enterprises that engage in sophisticated bank robberies. Imagine that the government can identify those enterprises by tracking down shell companies that have engaged in certain behaviors—say, opening a new bank account within x hours of a robbery and making deposits into that account between one and y hours post-robbery and then never again. Imagine further that the government has studied the behavior of particular criminal enterprises and knows that for Enterprise A, "x" equals 48 hours and "y" equals 12 hours, but that for Enterprise B, "x" equals 24 hours and "y" equals 6 hours. Armed with details about their behavioral patterns, the government would be able to identify which criminal enterprise likely robbed a particular bank. And were that information ever to be made public, both Enterprise A and Enterprise B would be able to evade detection by changing their distinctive behaviors....
....MUCH MORE
