Weeks before the Russian invasion of Ukraine, an anonymous Bitcoin user sounded the alarm and called out 986 addresses they claim belong to Russian security agencies. How did they do it? OP_RETURNs. This blockchain vigilante burned over $300,000 worth of Bitcoin across over 1,000 transactions to embed their accusations in the OP_RETURN field. https://preview.redd.it/rq1ps6uuvgwa1.jpg?width=2048&format=pjpg&auto=webp&v=enabled&s=17ba2ce1c86c6accf0482bf83e883d82284cbf64 Under ordinary circumstances, it would be difficult to detect cryptocurrency addresses used by hostile actors unless you were actively looking for them. But starting on February 12, 2022 — weeks before the Russian invasion of Ukraine — and ending on March 14, 2022, an anonymous Bitcoin user sounded the alarm and called out nearly 1,000 addresses they claim belong to Russian security agencies. How did they do it? OP_RETURNs. OP_RETURN is a field used to mark Bitcoin transactions as invalid, but can al...