need SUBSTITUTE help

[TommyMedium]

So it has been a little side project of mine to make a spreadsheet with a "secret-decoder" approach. Essentially what needs to happen is a substitution, or letter swap, to encrypt a message. For example; letter "A"or"a" equals another letter from the alphabet such as "K"or"k". Any ideas??? Does this make sense to you??? Does each letter need to be in a different cell???

 

[c_m]

Hello and Welcome to the Board.
Can you provide an example?