SketchBooks SecretWritingVan Eck Phreaking is the name for a surveillance technology which is, that intelligence services are able to reconstruct the content of a computermonitor by picking up the electromagnetic(em)-field of the computermonitor. over the years, programmers developed methods and algorithms to convert em-fields to screen ghosts to view screen data without using cables or cameras. Van Eck Phreaking is a form of eavesdropping in which special equipment is used to pick up telecommunication signals or data within a computer device by monitoring and picking up the em-fields. the U.S. government has been involved with em-field interpretation for many years under a top-secret program code-named “Tempest.”