affini.py

#coding: utf-8

import enchant

LAT = ['A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
        'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z']
a_list = [1, 3, 5, 7, 9, 11, 15, 17, 19, 21, 23, 25]
m = len(LAT)

CODE = """
NCPHIWDQ
"""

CODE_FULL = """
ZFA KAQG ZI VA SGAH CNA IVZCYPAH TNIW C KAQ GISNOA EFYOF GADAOZG ZFAW BANFCBG
NCPHIWDQ TNIW ZFA DCNMA GAZ IT CDD SGCVDA KAQG
"""

# 1 = a * aa % m
# 19 89 2, a a1 b
# THE KEYS TO BE USED ARE OBTAINED FROM A KEY SOURCE WHICH SELECTS THEM PERHAPS RANDOMLY FROM THE LARGE SET OF ALL USABLE KEYS

checker = enchant.Dict("en_US")


def decipher_whole(sentence, aa, b):
    result = ''
    for c in sentence:
        if c in LAT:
            code = LAT.index(c)
            x = aa * (code - b) % m
            result += LAT[x]
        else:
            result += ' '

    print result

for a in a_list:
    checked = False

    aas = set([])
    for aa in xrange(1, 100):
        try:
            assert a * aa % m == 1
            aas.add(aa)
        except:
            continue

    for aa in aas:
        for b in xrange(1, 1000):
            result = ''
            for c in CODE:
                if c in LAT:
                    code = LAT.index(c)
                    x = aa * (code - b) % m
                    result += LAT[x]
                else:
                    result += ' '

            result = result.replace(' ', '').lower()
            if checker.check(result):
                decipher_whole(CODE_FULL, aa, b)
                exit(0)