(IOTP, Formerly "Open Trading Protocol", OTP) A specification that provides an interoperable framework for Internet commerce. It is optimised for the case where the buyer and the merchant do not have a prior acquaintance and is payment system independent. It will be able to encapsulate and support payment systems such as SET, Mondex, CyberCash's CyberCoin, DigiCash's e-cash, GeldKarte, etc. IOTP is able to handle cases where such merchant roles as the shopping site, the payment handler, the deliverer of goods or services, and the provider of customer support are performed by different Internet sites. The IOTP specification is maintained by the IETF Internet Open Trading Protocol (trade) Working Group.