A wearable, non-visible identification device provides reliable, tamper-proof, friendly-force identification and intruder detection. The device is integrated as a part of the wearer's uniform and includes a user input surface for periodic entry of a unit- or user-defined pass code. A timeout capability prevents the device and its identification signal from being used if the pass code is not entered within the specified time period. The preferred embodiment uses non-visible optical identification signals for 1-way identification using standard tactical equipment, making the device useful in the field during operations or at temporary security control points away from established bases. Alternative embodiments use radio-frequency, visible and reflective identification signals. Identification signaling methods are effective at stand off ranges to minimize threat to security personnel. Very low cost and low power embodiments for use by security forces in developing nations are described. This invention provides a
