4 These breaches remind us that relying solely on cryptography within the transfer technology is not enough. Ultimately, a more holistic approach to the security of the broader cryptocurrency ecosystem, along with added layers of security on top of cryptography, are likely to be necessary for cryptocurrencies to be widely adopted.
Some cryptocurrencies also appear quite vulnerable to money-laundering (BSA/AML, or Bank Secrecy Act/anti-money-laundering) concerns. Since many cryptocurrencies store in their  2  See, for example, https://www.coinbase.com/charts. Lael Brainard, “An Update on the Federal Reserve’s Financial Stability Agenda” (speech delivered at the Center for Global Economy and Business, Stern School of Business, New York University, New York, NY, April 3, 2018), https://www.federalreserve.gov/newsevents/speech/brainard20180403a.htm.