Abstract: Preprinted forms are used in a general purpose printing device to allow for the subsequent verification of the authenticity of a printed document such as a ticket for transportation services. In operation, the user accesses the seller of the goods/services and during an information exchange with the seller the user inputs at least a portion of the preprinted data from the form. The seller then uses this information to formulate a printable control indicia which is then printed on the form at the user's location. When the form is subsequently presented to the seller, for example when the user attempts to board an aircraft using the form he/she printed, the preprinted portion of the form is used to obtain a decipher key which in turn is used to decipher the control indicia. Inability to decode the control indicia indicates that the printed material on the form may not be authentic.

Abstract: Universally available preprinted forms are used in a general purpose printing device to allow for the subsequent verification of the authenticity of a printed document such as a ticket, stamp, check, or money order. In operation, the user accesses the seller of the goods/services and during an information exchange with the seller there is inputted at least a portion of the preprinted data from the form. The seller then uses this information to formulate a printable control indicia which is then printed on the form at the user's location. When the form is subsequently presented to the seller, for example when the user uses the form he/she printed, the preprinted portion of the form is used to obtain a decipher key which in turn is used to decipher the control indica. If desired, a special security marking may be associated with the form for additional security. Inability to decode the control indicia indicates that the printed material on the form may not be authentic.