The Standard Transfer Specification is the global standard for the transfer of electricity and other utility prepayment tokens, ensuring inter-operability between system components from different manufacturers. It was first introduced in South Africa in 1993 and subsequently published by the International Electrotechnical Commission as the IEC62055 series of specifications. The application of the technology is licensed through the STS Association, thus ensuring that the appropriate key-management encryption practices are applied to protect the security of the prepayment transactions of utilities.