Correct! [ He's all too thrilled, he likes it when people understand something after all, and if Inigo is proud, Senku is proud of him too. ]

Those are some of the easier ciphers in history, but there are more complicated ones. Like Morse code, which might be more universal, and uses the roman alphabet or our Japanese-specific Uesugi cipher.

They predated modern technology like cell phones and radio waves.

[ He's such a nerd. ]