High Quality Content by WIKIPEDIA articles! The KOI-18 is a hand-held paper tape reader developed by the U.S. National Security Agency as a fill device for loading cryptographic keys, or "crypto variables," into security devices, such as encryption systems. It can read 8-level paper or PET tape, which is manually pulled through the reader slot by the operator. It is battery powered and has no internal storage, so it can load keys of different lengths, including the 128-bit keys used by more modern systems. The KOI-18 can also be used to load keys into other fill devices that do have internal storage, such as the KYK-13 and AN/CYZ-10. The KOI-18 only supports the DS-102 interface.