?

1. No matter , if the key on the left of the cipher 🔒 is public and the right side only the private key, how about a single key ꄗ symbol which is replaced according to its corresponding location relative to 🔒. y = ꄗ 🔒x encrypts x into y and x = y🔒ꄗ decrypts y back to x. If the cipher 🔒has asymmetric keys this works fine, and symmetric key ciphers by definition fits.