What is the term for the prevention of unauthorized access to information via electromagnetic emanations?

The correct term for the prevention of unauthorized access to information via electromagnetic emanations is "Tempest." This term originates from a U.S. government program designed to protect sensitive information from being intercepted through the unintentional release of electromagnetic signals. By employing Tempest countermeasures, organizations can reduce the risk of eavesdropping on information processed by electronic devices, which is crucial in maintaining confidentiality and protecting sensitive data.

The other options do not accurately describe this concept. For instance, "Veiling" refers to techniques that might obscure information but does not specifically pertain to electromagnetic emanations. "Bugging" typically relates to placing listening devices in an area to capture audio and does not focus on electromagnetic emissions. "Hardening" involves strengthening systems against attacks or intrusions, usually referring to software and hardware security, rather than addressing unauthorized access through electromagnetic signals. Thus, Tempest is the appropriate term utilized in this context.