def expandKey(inputKey):
cipherKeySize = len(inputKey)
assert cipherKeySize == 32
outputKey = [] #Container for expanded key
currentSize = 0
rconIteration = 1
temp = [0]*4 #Temporary byte list to store 4 bytes at a time
for i in range(cipherKeySize):
outputKey.append(inputKey[i])
currentSize += cipherKeySize
while currentSize < 240:
for i in range(4):
temp[i] = outputKey[(currentSize -4)+i]
if currentSize % cipherKeySize == 0:
temp = keyScheduleCore(temp, rconIteration)
rconIteration += 1
if currentSize % cipherKeySize == 16:
temp = subBytes(temp)
for i in range(4):
outputKey.append(((outputKey[currentSize-cipherKeySize]) ^ (temp[i])))
currentSize +=1
return outputKey
def keyScheduleCore(inputWord, i):
oWord = subBytes(inputWord[1:]+inputWord[:1])
oWord[0] = oWord[0] ^ getRcon(i)
return oWord