I wonder where the borders lie between encryption and deliberate obfuscation - say, by native speakers of a little-known language (which was done for some WWII radio transmissions by the US [1]) and also to a far lesser extent by old-time London gangs using Cockney rhyming slang and variants thereof. [2]

[1] https://www.nationalww2museum.org/war/articles/american-indi...

[2] https://romanroadlondon.com/cockney-rhyming-slang-history/