U.S. Army Special Forces used one-time pads in Vietnam. By using Morse code with one-time pads and continuous wave radio transmission (the carrier for Morse code), they achieved both secrecy and reliable communications.
Us army sPecial forCEs Used One-tIme PaDs in VIeTNAm by USiNg mORSe Code wIth OnE-time pads and coNtiNuous WaVE rAdio TRaNsmIssIOn (THe cArrIer foR MoRse code) TheY AchieveD botH secrecy and relIabLe cOmmuniCatiONS