Bitcoin Fog operator’s conviction upheld without Chainalysis disclosing source code
What happened
On Sept. 25, 2026, a federal appeals court upheld Roman Sterlingov’s conviction and 150‑month prison sentence for operating the Bitcoin Fog mixer. The court rejected Sterlingov’s request to obtain the source code for Chainalysis Reactor, while allowing his lawyers to review the software’s heuristics under a protective order.
Key numbers
- 150‑month prison sentence
- Sept. 25, 2026 – date of the appellate ruling
- Over 900,000 Bitcoin addresses attributed to Bitcoin Fog
- Four of five known Bitcoin Fog addresses matched by Reactor
- 99.9% clustering accuracy reported in a separate case
What the court says about the source code
The district court ordered that Reactor’s heuristics and underlying assumptions be made available to Sterlingov’s counsel and qualified experts, but only under a protective order. The appellate opinion notes that the court repeatedly asked Sterlingov to explain why the source code was material to his defense. Sterlingov did not provide such an explanation, and his experts refused to review even the disclosed heuristics.
Why the source‑code challenge failed
The court determined that the request for full source code disclosure was not justified. The judge cited concerns about preserving the software’s integrity and the need for a clear link between the code and the defense. Because Sterlingov could not show how the source code would affect his case, the request was denied. His experts further declined to examine the available heuristic documentation.
What is confirmed
• The appeal upheld the admission of Reactor expert testimony under Daubert standards. • Reactor’s clustering methods (co‑spend, behavioral, and intelligence‑based) were explained and corroborated. • The original conviction and 150‑month sentence remain in effect. • The court accepted the panel’s view that Reactor performed conservatively in this case.
Why it matters
The ruling sets a precedent for using proprietary blockchain analysis tools as courtroom evidence without full source disclosure. It shows that courts may accept expert testimony based on internal software if reliability is demonstrated, influencing future digital‑forensics cases.
Official source
The D.C. Circuit opinion (https://media.cadc.uscourts.gov/opinions/docs/2026/09/24-3161-2194974.pdf) affirmed the district court’s decisions, including the rejection of the source‑code request. The opinion explains the court’s reasoning under Daubert and clarifies how Reactor’s expert testimony met reliability standards.
Other sources
Chainalysis published a blog commentary on Oct. 13 (https://www.chainalysis.com/blog/chainalysis-daubert-standard-appeal/) that highlighted the judgment as further validation of its Reactor software. The blog emphasizes the decision’s support for using proprietary tools in legal proceedings.
Sources
Newisty Editorial Team covers technology, cryptocurrency, digital products, online platforms, developer tools and the wider digital economy. Our content is researched from official sources, company announcements, public documentation, market data and other primary or reputable sources. Articles are reviewed and edited before publication for clarity, accuracy and useful context.