import binascii

def num2str(n):
    return hex2str(num2hex(n))

def str2num(s):
    return hex2num(str2hex(s))

def num2hex(n):
    return ("%x" % int(n))

def str2num(s):
    return int(binascii.hexlify(s), 16)

def hex2num(h):
    return int(h, 16)

def str2hex(s):
    return binascii.hexlify(s)

def hex2str(s):
    return binascii.unhexlify(s)

def invMod(a, n):
    t = 0
    newt = 1
    r = n
    newr = a
    while newr != 0:
        q = r // newr
        (t, newt) = (newt, t - q * newt)
        (r, newr) = (newr, r - q * newr)
    if r > 1:
        raise Exception('unexpected')
    if t < 0:
        t += n
    return t

def generate():
    primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47]
    e, phi, N = 29, 1, 1
    for p in primes:
        phi *= (p-1)
        N *= p
    d = invMod(e, phi)
    return e, N, d

def encrypt(plain, e, N):
    return pow(plain, e, N)

def decrypt(cipher, d, N):
    return pow(cipher, d, N)

if __name__ == '__main__':                                  
    e, N, d = generate()
    plain = "Rahasia"
    cipher = encrypt(str2num(plain), e, N)        
    plains = decrypt(cipher, d, N)
    print "Cipher: ", cipher
    print "Plain: ", num2str(plains)
    assert plain == num2str(plains)
    print pow(N, d, N)
    print pow(N+2, d, N)
    print d, N