page_title: Tempest (codename)
hierarchical_section_title: Tempest (codename)
caption_attribution_description: English: Type 131B2 mixer, used by the U.S. to encrypt teletypewriter transmissions during World War II and up to 1960 by combining plaintext data with a binary key stream using the XOR operation. Used with w:SIGTOT one-time-tape and w:SIGSUM key generator. Later renamed AN/FGQ-1. Unit photographed from the rear with grill removed. Large cylinders are WEco. 255 polar relays.
context_page_description: TEMPEST is a U.S. National Security Agency specification and a NATO certification referring to spying on information systems through leaking emanations, including unintentional radio or electrical signals, sounds, and vibrations. TEMPEST covers both methods to spy upon others and how to shield equipment against such spying. The protection efforts are also known as emission security, which is a subset of communications security.
  The NSA methods for spying on computer emissions are classified, but some of the protection standards have been released by either the NSA or the Department of Defense. Protecting equipment from spying is done with distance, shielding, filtering, and masking. The TEMPEST standards mandate elements such as equipment distance from walls, amount of shielding in buildings and equipment, and distance separating wires carrying classified vs. unclassified materials, filters on cables, and even distance and shielding between wires or equipment and building pipes. Noise can also protect information by masking the actual data.
  While much of TEMPEST is about leaking electromagnetic emanations, it also encompasses sounds and mechanical vibrations.
context_section_description: TEMPEST (Telecommunications Electronics Materials Protected from Emanating Spurious Transmissions) is a U.S. National Security Agency specification and a NATO certification referring to spying on information systems through leaking emanations, including unintentional radio or electrical signals, sounds, and vibrations. TEMPEST covers both methods to spy upon others and how to shield equipment against such spying. The protection efforts are also known as emission security (EMSEC), which is a subset of communications security (COMSEC).
  The NSA methods for spying on computer emissions are classified, but some of the protection standards have been released by either the NSA or the Department of Defense. Protecting equipment from spying is done with distance, shielding, filtering, and masking. The TEMPEST standards mandate elements such as equipment distance from walls, amount of shielding in buildings and equipment, and distance separating wires carrying classified vs. unclassified materials, filters on cables, and even distance and shielding between wires or equipment and building pipes. Noise can also protect information by masking the actual data.
  While much of TEMPEST is about leaking electromagnetic emanations, it also encompasses sounds and mechanical vibrations. For example, it is possible to log a user's keystrokes using the motion sensor inside smartphones. Compromising emissions are defined as unintentional intelligence-bearing signals which, if intercepted and analyzed (side-channel attack), may disclose the information transmitted, received, handled, or otherwise processed by any information-processing equipment.
caption: Bell 131B2 mixer, used to XOR teleprinter signals with one time tapes, was the first device from which classified plain text was extracted using radiated signals.
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