KIK13s here, to program IFF systems in AF planes.
Used to pull a masking tape looking paper strip, with hundreds of seemingly random dots punched in it, through the KIK13 device to read the code, then use the KIK13 to program the plane’s transponder. Final test was to “shoot” the plane with a coded view-master looking tester to verify system operation.
This process became a required preflight item after a friendly helo was mistaken for then enemy, and shot down during the first gulf war. They blamed a faulty IFF transponder for the incident.
First and last encryption key I’ve ever physically held.
KIK13s here
Actually the “tape” was pulled through a KOI-18 that was connected to the KYK-13. This loaded the key into the KYK and could subsequently be loaded into a radio or other device.