摘要 |
A method of securely transmitting communication information from a first terminal operating in a first coordinate measurement domain to a second remotely-located terminal operating in a second coordinate measurement domain is described. The method comprises: combining the communication information with extraneous information to create a data signal; determining a value of an identification variable expressed with respect to the first coordinate measurement domain, the identification variable value enabling the location of the communication information concealed within the data signal to be determined; transmitting the data signal and the identification variable value from the first terminal to the second terminal; using a coordinate transform function configured to map coordinate values from the first coordinate measurement domain to the second coordinate measurement domain to calculate a value of the received identification variable expressed with respect to the second coordinate measurement domain; and extracting the information from the received data signal using the calculated identification variable value to distinguish the communication information from the extraneous information. |