def inv(column):
fixedmatrix = bytearray([0x0e, 0x0b, 0x0d, 0x09])
mixcolumnmatrix = bytearray()
for i in range(0, 4):
resultinglist = []
rijndael = gf.makeblist(0x11b)
for j in range(0, 4):
fixedbitlist = gf.makeblist(fixedmatrix[j])
columnvector = gf.makeblist(column[j])
resultingbyte = gf.mul(fixedbitlist, columnvector)
while gf.value(resultingbyte) > 255:
# note the inverted division function!
resultingbyte = gf.div(rijndael, resultingbyte)[1]
resultinglist.append(resultingbyte)
finalvalue = gf.add(resultinglist[0], resultinglist[1])
finalvalue = gf.add(finalvalue, resultinglist[2])
finalvalue = gf.add(finalvalue, resultinglist[3])
mixcolumnmatrix.append(gf.value(finalvalue))
fixedmatrix = gf.circrotateright(fixedmatrix)
return mixcolumnmatrix
def mix(column):
fixedmatrix = bytearray([0x02, 0x03, 0x01, 0x01])
mixcolumnmatrix = bytearray()
for i in range(4):
resultinglist = []
rijndael = gf.makeblist(0x11b)
for j in range(4):
fixedbytelist = gf.makeblist(fixedmatrix[j])
columnvector = gf.makeblist(column[j])
resultingbyte = gf.mul(fixedbytelist, columnvector)
if gf.value(resultingbyte) > 255:
resultingbyte = gf.div(resultingbyte, rijndael)[1]
resultinglist.append(resultingbyte)
finalvalue = gf.add(resultinglist[0], resultinglist[1])
finalvalue = gf.add(finalvalue, resultinglist[2])
finalvalue = gf.add(finalvalue, resultinglist[3])
mixcolumnmatrix.append(gf.value(finalvalue))
fixedmatrix = gf.circrotateright(fixedmatrix)
return mixcolumnmatrix
def maketable():
rcontable = []
rcontable.append([1, 0, 0, 0, 1, 1, 0, 1]) # rcon[0]
rcon = gf.makeblist(0x01)
rijn = gf.makeblist(0x11b)
for i in range(52):
rcontable.append(rcon)
# this is actually a leftwise shift, multiply by 2
rcon = gf.mul(rcon, [0, 0, 0, 0, 0, 0, 1, 0])
if gf.value(rcon) > 255:
# take the remainder from division operation (modulus)
rcon = gf.div(rcon, rijn)[1]
return rcontable
def make():
table = []
for i in range(0, 256):
bitlist = gf.makeblist(int(i))
table.append(gf.inverse(bitlist))
affmatrix = aff.makematrix()
sbox = []
for i in range(0, 256):
sbox.append(aff.transform(table[i], affmatrix))
for i in range(0, 256):
sbox[i] = bytes([gf.value(sbox[i])])
return sbox
def makeroundkey(previouskey, round, rcontable, subbox): # Split the key to 4 byte slices: w0 = bytearray(previouskey[0:4]) w1 = bytearray(previouskey[4:8]) w2 = bytearray(previouskey[8:12]) w3 = bytearray(previouskey[-4:]) # Perform a circular byte left shift to w3: [0,1,2,3] -> [1,2,3,0] gw3 = bytearray(w3[1:] + w3[:1]) # Apply Rijndael S-box to gw3 bytes (substitution): for i in range(len(gw3)): gw3[i] = int.from_bytes(subbox[gw3[i]], byteorder='big') # Add round constant to the leftmost byte in gw3 # Adding is in GF rconbyte = gf.makeblist(gw3[0]) gw3[0] = gf.value(gf.add(rcontable[round], rconbyte)) # Build the roundkey: w4 = bytearray(4) w5 = bytearray(4) w6 = bytearray(4) w7 = bytearray(4) for i in range(4): w4[i] = gw3[i] ^ w0[i] for i in range(4): w5[i] = w4[i] ^ w1[i] for i in range(4): w6[i] = w5[i] ^ w2[i] for i in range(4): w7[i] = w6[i] ^ w3[i] roundkey = w4 + w5 + w6 + w7 return roundkey
def makeinverse():
sbox = []
for i in range(0, 256):
bitlist = gf.makeblist(int(i))
gf.removeleadingzero(bitlist)
sbox.append(bitlist)
affmatrix = aff.makeinversematrix()
for i in range(0, 256):
sbox[i] = aff.inversetransform(sbox[i], affmatrix)
sbox[i] = gf.inverse(sbox[i])
for i in range(0, 256):
sbox[i] = bytes([gf.value(sbox[i])])
#aff.printmatrix(sbox)
return sbox