When I was about 12 years old, my father introduced me to the fine art of numismatics, otherwise known as coin collecting, by giving me a Whitman Roosevelt Dime collectors book. He probably intended that I have a backup plan in case the court I spent most of my time in then—the basketball court—did not work out for me. In order to fill the book's empty dime slots, you had to get all dimes minted from 1946 through 1964. It was no easy feat. It required regular visits to the local bank branch, waiting in long lines, and exchanging hard earned dollar bills for five dollar rolls of dimes. Then followed the arduous task of cleaning and scrutinizing the coins at home for the special minted markings that would identify that small silver nugget as a thing that was worth more than its face value. That was my pre-Internet world of “currency transactions.” Today, we have digital currencies that are not limited by country or continent, and that may be traded online in “digital wallets,” as referenced in United States v. Ulbricht, 2017 U.S. App. LEXIS 9517 (May 31, 2017).

Last month in Ulbricht, the U.S. Court of Appeals for the Second Circuit upheld the legality of evidence obtained as a result of court-ordered pen registers that federal agents obtained for defendant's Internet routing data. The evidence provided a key link connecting defendant's online activity to a massive narco-money laundering Bitcoin criminal enterprise scheme that thrived through a website he created called Silk Road.

The defendant contended that his Fourth Amendment rights had been violated when the government failed to obtain search warrants that required the probable cause standard to obtain the sought after data and instead utilized pen registers under the “Pen/Trap Act,” pursuant to 18 U.S.C. §§3121-27, which requires a much more relaxed standard. See Ashcroft v. al-Kidd, 563 U.S. 731 (2011) (“The Fourth Amendment was a response to the English Crown's use of general warrants, which often allowed royal officials to search and seize whatever and whomever they pleased while investigating crimes or affronts to the Crown.”). The significance of this ruling in light of established Fourth Amendment jurisprudence will be addressed in this article.