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 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 makematrix():
matrixbits = [0, 0, 0, 1, 1, 1, 1, 1] # 0x1F
affmatrix = []
for i in range(8):
matrixbits = gf.circrotateright(matrixbits)
affmatrix.append(matrixbits)
return affmatrix
def makeinversematrix():
matrixbits = [0, 1, 0, 0, 1, 0, 1, 0] # inverse of 0x1F (in GF?)
affmatrix = []
for i in range(8):
matrixbits = gf.circrotateright(matrixbits)
affmatrix.append(matrixbits)
return affmatrix
def do(state):
r0, r1, r2, r3 = bytearray(), bytearray(), bytearray(), bytearray()
for i in range(4):
r0.append(state[i * 4])
r1.append(state[1 + i * 4])
r2.append(state[2 + i * 4])
r3.append(state[3 + i * 4])
r1 = gf.circrotateleft(r1)
r2 = gf.circrotateleft(gf.circrotateleft(r2))
r3 = gf.circrotateright(r3)
newstatematrix = r0 + r1 + r2 + r3
return newstatematrix