This cipher is run with Python, but here you can run it in the browser.

import string import math while True: ed = input("Encrypt or decrypt? (e/d): ") if ed != "d": print("---Encrypter---\n\n") raw = input("Plaintext: ") st = int(string.ascii_letters.index(raw[0])) + 1 code = "" for lettr in raw: if lettr in string.ascii_letters: number = (string.ascii_letters.index(lettr) + 1) * st code = code + str(number) + "@" elif lettr == " ": code = code + "&@" else: code = code + "!" print(code) elif ed == "d": print("---Decrypter---\n\n") raw = input("Encrypted: ").replace("!", "").replace("&", " ").split("@") st = math.sqrt(int(raw[0])) plain = "" for num in raw: if num != " " and num != "": letter = string.ascii_letters[int((int(num)/st)-1)] plain = plain + letter else: plain = plain + num print(plain)