def genTables():
c = BitVector(bitstring='01100011')
d = BitVector(bitstring='00000101')
for i in range(0, 256):
# For the encryption SBox
a = BitVector(intVal=i, size=8).gf_MI(
AES_modulus, 8) if i != 0 else BitVector(intVal=0)
# For bit scrambling for the encryption SBox entries:
a1, a2, a3, a4 = [a.deep_copy() for x in range(4)]
a ^= (a1 >> 4) ^ (a2 >> 5) ^ (a3 >> 6) ^ (a4 >> 7) ^ c
subBytesTable.append(int(a))
# For the decryption Sbox:
b = BitVector(intVal=i, size=8)
# For bit scrambling for the decryption SBox entries:
b1, b2, b3 = [b.deep_copy() for x in range(3)]
b = (b1 >> 2) ^ (b2 >> 5) ^ (b3 >> 7) ^ d
check = b.gf_MI(AES_modulus, 8)
b = check if isinstance(check, BitVector) else 0
invSubBytesTable.append(int(b))
return subBytesTable, invSubBytesTable
def getDecryptionSubBox():
dbox = [[0 for i in range(16)] for j in range(16)]
modulus = BitVector(bitstring='100011011')
n = 8
d = BitVector(bitstring='00000101')
for i in range(16):
for j in range(16):
i_s = bin(i)[2:].zfill(4)
j_s = bin(j)[2:].zfill(4)
bv = BitVector(bitstring=i_s + j_s)
dboxt = bv.deep_copy()
for k in range(8):
bv[k] = dboxt[(k - 2) % 8] ^ dboxt[(k - 5) % 8] ^ dboxt[
(k - 7) % 8] ^ d[k]
if bv.get_hex_string_from_bitvector() != '00':
dbox[i][j] = bv.gf_MI(modulus, n)
else:
dbox[i][j] = BitVector(bitstring='00000000')
dbox[i][j] = dbox[i][j].get_hex_string_from_bitvector()
return dbox
def getEncryptionSubBox():
sbox = [[0 for i in range(16)] for j in range(16)]
modulus = BitVector(bitstring='100011011')
n = 8
c = BitVector(bitstring='01100011')
for i in range(16):
for j in range(16):
if i == 0 and j == 0:
bv = BitVector(bitstring='00000000')
sbox[i][j] = bv
else:
i_s = bin(i)[2:].zfill(4)
j_s = bin(j)[2:].zfill(4)
bv = BitVector(bitstring=i_s + j_s)
sbox[i][j] = bv
sbox[i][j] = bv.gf_MI(modulus, n)
sboxt = sbox[i][j].deep_copy()
for k in range(8):
sbox[i][j][k] = sboxt[k] ^ sboxt[(k - 4) % 8] ^ sboxt[
(k - 5) % 8] ^ sboxt[(k - 6) % 8] ^ sboxt[(k - 7) %
8] ^ c[k]
sbox[i][j] = sbox[i][j].get_hex_string_from_bitvector()
return sbox
a = 0 b = 0 if response.ok: res = response.json() print(res) a, b = res['a'], res['b'] #Binary polynomials a and b else: print(response.json()) ##SOLUTION modulus = BitVector(bitstring = '100011011') n = 8 a = BitVector(bitstring = '11001001') multi_inverse = a.gf_MI(modulus, n) modulus = BitVector(bitstring='100011011') # AES modulus n = 8 a = BitVector(bitstring='11001001') b = BitVector(bitstring='11011001') mult = a.gf_multiply_modular(b, modulus, n) #You need to calculate c and a_inv #c = a(x)*b(x) #a_inv is inverse of a c = mult a_inv = multi_inverse ##END OF SOLUTION
