Most of us know about voice scrambler that can be used across almost any kind of voice based communication technology.

Extremely flexible approach: works everything

Extreme performance: very low latency

but unfortunately…

Extremely weak: Scrambling cannot be considered secure.

Only encryption can be considered secure under the Kerckoff’s principle .

So please don’t even consider any kind of analog scrambler if you need real security.

Read deeply the paper Implementation of a real-time voice encryption system” by Markus Brandau, especially the cryptoanalysis paragraph.