CBDC's are different than regular digital cash forms like in online bank accounts because CBDC's are established through the central bank within a country, with liabilities held by one's government, rather than from a commercial bank. Approximately nine countries have already established a Central Bank Digital Currency, with interest in the system increasing highly throughout the world. In these nations, CBDC's have been used as a form of exchange and a way for governments to try and prevent risks from occurring within their financial systems. Decentralized systems Digital Currency has been implemented in some cases as a decentralized system of any combination of currency issuance, ownership record, ownership transfer authorization and validation, and currency storage. Per the Bank for International Settlements (BIS), "These schemes do not distinguish between users based on location, and therefore allow value to be transferred between users across borders. Moreover, the speed of a transaction is not conditional on the location of the payer and payee." Law Since 2001, the European Union has implemented the E-Money Directive "on the taking up, pursuit and prudential supervision of the business of electronic money institutions" last amended in 2009. In the United States, electronic money is governed by Article 4A of the Uniform Commercial Code for wholesale transactions and the Electronic Fund Transfer Act for consumer transactions. Provider's responsibility and consumer's liability are regulated under Regulation E. Regulation Virtual currencies pose challenges for central banks, financial regulators, departments or ministries of finance, as well as fiscal authorities and statistical authorities. Adoption by governments As of 2016, over 24 countries are investing in distributed ledger technologies (DLT) with $1.4bn in investments. In addition, over 90 central banks are engaged in DLT discussions, including implications of a central bank issued digital currency. Hong Kong's Octopus card system: Launched in 1997 as an electronic purse for public transportation, is the most successful and mature implementation of contactless smart cards used for mass transit payments. After only 5 years, 25 percent of Octopus card transactions are unrelated to transit, and accepted by more than 160 merchants. London Transport’s Oyster card system: Oyster is a plastic smartcard that can hold pay-as-you-go credit, Travelcards and Bus & Tram season tickets. An Oyster card can be used to travel on bus, Tube, tram, DLR, London Overground and most National Rail services in London. Japan's FeliCa: A contactless RFID smart card, used in a variety of ways