External Encrypted Microphone Hardware for Cellphone?

I am aware of encrypted messaging apps that even allow phone calls like Signal or Telegram and such, but I am curious... Is there any sort of 3rd party external hardware that one could use with their phone to encrypt their voice, transmit the traffic, have it received by the other phone, and decrypted with their external hardware that is programmed with the same encryption/decryption as the sender. Is such a thing commercially available? Or if you think this is …

cellphone encrypted hardware microphone privacy