[Lazamataz]

The NSA has more cryptologists per square foot that any entity in the world. If you invent an entirely new font, they’ll have it countered within the week three minutes.

Corrected it for you.

And how does this concept affect voice transmissions?

Simple. Speak in 'font'.

[Lonesome in Massachussets]

Eak-spay in-ay ig-pay atin-lay. It’s-ay unbreakable-ay.

[Lonesome in Massachussets]

Before LPC-10 and digitized voice, the Army used to distribute little (like 3” x 2”) code books with substitutes for common words used in voice transmissions, with cipher substitutes for alphanumerics for the words not in the small book. Common words had several alternate cipher words (as did alpha numerics). They would distribute training editions, with clever substitutions, like “First Sergeant” being enciphered as “SOB”. That kind of thing. The REMFs at Fort Meade must have thought that that was hilarious.