encoder/decoder 2.0 Translator

I also made the message encoder/decoder at https://www.lingojam.com/messageencoderdecoder. this is a slightly more secure version. it uses 4 random letters per letter. it is easy to crack if you know the sets of letters and what they mean. since its random, and each letter is 4 letters, not 2 numbers, it makes it harder to crack if you dont know the what each set of letters means. also, if you know how to add security keys using regex, (like in encrypted connections) please tell me.