1. An apparatus configured to allow a second party to authenticate a right of a user of a data transfer device to complete a transaction at a point of sale device associated with said second party, said apparatus comprising: a first data interface configured to communicate with said data transfer device; a second data interface configured to communicate with said point of sale device; and computerized logic in data communication with said first data interface and said second data interface, said computerized logic configured to cause said apparatus to: receive from said first data interface encrypted transaction information held in storage at said data transfer device, said transaction information comprising at least authentication data identifying one or more parties authorized to use said data transfer device; authenticate said right of said user of said data transfer device to decrypt a first portion of said encrypted transaction information by comparing a decrypted second portion of said encrypted authentication data stored at said data transfer device to identity data obtained from said user of said data transfer device; and upon authentication of said user: provide at least said decrypted first portion of said encrypted transaction information to said point of sale to complete said transaction via said second data interface; and transmit via said first data interface a record of said completed transaction for storage on said data transfer device, said record comprising at least one data structure received from said point of sale device comprising at least an encrypted indicator of a hashed electronic receipt.