simpleDecrypt.py

from string import ascii_lowercase


plainText = ""
cipherText = (
    "JNRZR BNIGI BJRGZ IZLQR OTDNJ GRIHT USDKR ZZWLG OIBTM NRGJN IJTZJ LZISJ NRSBL QVRSI ORIQT"
    "QDEKJ JNRQW GLOFN IJTZX QLFQL WBIMJ ITQXT HHTBL KUHQL JZKMM LZRNT OBIMI EURLW BLQZJ GKBJT"
    "QDIQS LWJNR OLGRI EZJGK ZRBGS MJLDG IMNZT OIHRK MOSOT QHIJL QBRJN IJJNT ZFIZL WIZTO MURZM"
    "RBTRZ ZKBNN LFRVR GIZFL KUHIM MRIGJ LJNRB GKHRT QJRUU RBJLW JNRZI TULGI EZLUK JRUST QZLUK"
    "EURFT JNLKJ JNRXR S"
)

# Table for cipher with self pairings to start
cipher = {letter : "" for letter in ascii_lowercase}
cipher[" "] = ""


def set_letter_in_cipher(cipherLetter, plainLetter):
    cipher[cipherLetter.lower()] = plainLetter.lower()
    
    decryptedString = ""

    for letter in cipherText:
        decryptedLetter = letter.lower()

        if decryptedLetter in cipher and cipher[decryptedLetter]:
            decryptedLetter = cipher[decryptedLetter]
        elif letter is " ":
            decryptedLetter = " "
        else:
            decryptedLetter = "-"

        decryptedString = decryptedString + decryptedLetter

    plainText = decryptedString

    print "\n"+cipherText+"\n"
    print "\n"+plainText+"\n"


def print_cipher():
    print "\nCipher Letter | Plain Letter"
    print "----------------------------"

    for cipherLetter in cipher:
        if cipherLetter is not cipher[cipherLetter]:
            print "      "+cipherLetter+"          "+cipher[cipherLetter]