#frequency analysis
#This will both encode and decode message. Returns encrypted messages.
def Encrypt(message,key):
return [(int(message[i]) ^ key[i%len(key)]) for i in range(0,len(message))]
def Crypto(message,keyLength):
maxSize = 0
for i in range(0,len(message)):
if int(message[i]) > maxSize:
maxSize = int(message[i])
key = [0] * keyLength
nData = [[0] * keyLength, [0] * (maxSize+1)]
for i in range(0,len(message)):
j = i % keyLength
nData[j][int(message[i])] += 1
if nData[j][int(message[i])] > nData[j][key[j]]:
key[j] = int(message[i])
spaceAscii =32
for i in range(0,keyLength):
key[i] = key[i] ^ spaceAscii
return key
message = open("p059_cipher.txt","r").read().split(",")
keyLength = 3
key = Crypto(message,keyLength)
decryptedMessage = Encrypt(message,key)
print(decryptedMessage)
#Next sum decryptedMessage.
