def bin_to_ascii(ba):
ba = bytearray(ba)
data = ''
for i in range(len(ba)):
temp = hex(ba[i])
data = data + temp
return data
def CBC(data, lastCipher):
# pad
temp = data + ('0' * (32 - len(data)))
temp = int(lastCipher, 16) ^ int(temp, 16)
temp = hex(temp)
# fix length
temp = ('0' * (32 - len(temp))) + temp
return temp
def core(val):
global roundNum
RCon = modz(1 << roundNum)
val = val[2:] + val[:2]
ret = sub(val)
swap = hex(int(ret[:2], 16) ^ RCon)
ret = swap + ret[2:]
roundNum = roundNum + 1
return ret
def inverse(x, b=aes_b):
ix = int(x, 16)
if (ix > b):
ix = modz(ix, b)
bx = bin(ix)
q_list = []
tempdiv = b
tempq, tempr = divide(ix, tempdiv)
while tempr != 0:
q_list.append(tempq)
tempdiv = ix
ix = tempr
tempq, tempr = divide(ix, tempdiv)
ret = hex(EEA(q_list))
return ret
def expand(key, encrypt=True):
try:
test = int(key, 16)
except:
print("Invalid input type. Please enter hex value.")
return 1
keylen = len(key) * 4
if (keylen != 128) and (keylen != 192) and (keylen != 256):
print("Invalid key length. Please use 128, 192, or 256 bit key.")
return 2
numRounds = 10 + int((keylen - 128) / 32)
# 16 byte keys, 1 byte = 2 chars
expKeyLen = (numRounds + 1) * 16 * 2
expKey = key
global roundNum
roundNum = 0
# max value of j from key expansion loop
iterMax = 4 + (numRounds - 10)
while len(expKey) < expKeyLen:
# 4,6,8 for 128, 192, 256 bit keys
for i in range (iterMax):
temp1 = expKey[len(expKey) - 8:]
if i == 0:
temp1 = core(temp1)
if (i == 4) and (iterMax == 8):
temp1 = sub(temp1)
temp2 = expKey[len(expKey) - (8 * iterMax):]
temp2 = temp2[:8]
xor = hex(int(temp1, 16) ^ int(temp2, 16))
xor = '0' * (8 - len(xor)) + xor
expKey = expKey + xor
expKey = expKey[:expKeyLen]
roundKeys = []
for i in range(numRounds + 1):
roundKeys.append(expKey[i*32:(i+1)*32])
if not encrypt:
roundKeys.reverse()
return roundKeys
def mix_cols(data, encrypt=True):
multMat = mixMat if encrypt else invMat
# convert string to matrix
tmpMat = strToMat(data)
ret = []
# each column of data
for i in range(4):
ret.append([])
# each row of mult matrix
for j in range(4):
tmp = 0
# each item in the row
for k in range(4):
tmp = tmp ^ int(multiply(multMat[j][k], tmpMat[k][i]), 16)
tmp = modz(tmp)
# convert to string
tmp = hex(tmp)
ret[i].append(tmp)
# convert matrix back to string
tmp = []
for i in range(4):
tmp.append(''.join(ret[i]))
ret = ''.join(tmp)
return ret
def EEA(q_list):
k_list = [0b0, 0b1]
for i in range(len(q_list)):
k_list.append(k_list[i]
^ int(multiply(hex(k_list[i + 1]), hex(q_list[i])), 16))
return k_list[len(k_list) - 1]