During the latter part of the 20th century, foreign currency markets were revolutionized by the arrival of the digital computer and the ability to automate order books via electronic exchanges. The Nixon administration, in 1973, ended the Bretton Woods agreement paving the way for a marriage between currency and computers. Money is now represented by bits on a digital ledger rather than paper currency, making international control over the printing of currency infeasible. Past monetary systems, such as the one under the Bretton Woods agreement, relied on the difficulty of passable counterfeit currency as well as physically securing the currency printing plates to ensure that countries were not creating unauthorized inflation. As opposed to paper currency, centrally managed computer systems hosting digital ledgers do not have this property, allowing “double spending” which, when exploited, leads to uncontrollable inflation.