480 lines
9.6 KiB
Python
480 lines
9.6 KiB
Python
|
# Pure Python AES encryption routines.
|
||
|
|
#
|
||
|
|
# AES is integer based and inplace so doesn't use the heap. It is therefore
|
||
|
|
# a good test of raw performance and correctness of the VM/runtime.
|
||
|
|
#
|
||
|
|
# The AES code comes first (code originates from a C version authored by D.P.George)
|
||
|
|
# and then the test harness at the bottom.
|
||
|
|
#
|
||
|
|
# MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
|
||
|
|
|
||
|
|
##################################################################
|
||
|
|
# discrete arithmetic routines, mostly from a precomputed table
|
||
|
|
|
||
|
|
# non-linear, invertible, substitution box
|
||
|
|
aes_s_box_table = bytes(
|
||
|
|
(
|
||
|
|
0x63,
|
||
|
|
0x7C,
|
||
|
|
0x77,
|
||
|
|
0x7B,
|
||
|
|
0xF2,
|
||
|
|
0x6B,
|
||
|
|
0x6F,
|
||
|
|
0xC5,
|
||
|
|
0x30,
|
||
|
|
0x01,
|
||
|
|
0x67,
|
||
|
|
0x2B,
|
||
|
|
0xFE,
|
||
|
|
0xD7,
|
||
|
|
0xAB,
|
||
|
|
0x76,
|
||
|
|
0xCA,
|
||
|
|
0x82,
|
||
|
|
0xC9,
|
||
|
|
0x7D,
|
||
|
|
0xFA,
|
||
|
|
0x59,
|
||
|
|
0x47,
|
||
|
|
0xF0,
|
||
|
|
0xAD,
|
||
|
|
0xD4,
|
||
|
|
0xA2,
|
||
|
|
0xAF,
|
||
|
|
0x9C,
|
||
|
|
0xA4,
|
||
|
|
0x72,
|
||
|
|
0xC0,
|
||
|
|
0xB7,
|
||
|
|
0xFD,
|
||
|
|
0x93,
|
||
|
|
0x26,
|
||
|
|
0x36,
|
||
|
|
0x3F,
|
||
|
|
0xF7,
|
||
|
|
0xCC,
|
||
|
|
0x34,
|
||
|
|
0xA5,
|
||
|
|
0xE5,
|
||
|
|
0xF1,
|
||
|
|
0x71,
|
||
|
|
0xD8,
|
||
|
|
0x31,
|
||
|
|
0x15,
|
||
|
|
0x04,
|
||
|
|
0xC7,
|
||
|
|
0x23,
|
||
|
|
0xC3,
|
||
|
|
0x18,
|
||
|
|
0x96,
|
||
|
|
0x05,
|
||
|
|
0x9A,
|
||
|
|
0x07,
|
||
|
|
0x12,
|
||
|
|
0x80,
|
||
|
|
0xE2,
|
||
|
|
0xEB,
|
||
|
|
0x27,
|
||
|
|
0xB2,
|
||
|
|
0x75,
|
||
|
|
0x09,
|
||
|
|
0x83,
|
||
|
|
0x2C,
|
||
|
|
0x1A,
|
||
|
|
0x1B,
|
||
|
|
0x6E,
|
||
|
|
0x5A,
|
||
|
|
0xA0,
|
||
|
|
0x52,
|
||
|
|
0x3B,
|
||
|
|
0xD6,
|
||
|
|
0xB3,
|
||
|
|
0x29,
|
||
|
|
0xE3,
|
||
|
|
0x2F,
|
||
|
|
0x84,
|
||
|
|
0x53,
|
||
|
|
0xD1,
|
||
|
|
0x00,
|
||
|
|
0xED,
|
||
|
|
0x20,
|
||
|
|
0xFC,
|
||
|
|
0xB1,
|
||
|
|
0x5B,
|
||
|
|
0x6A,
|
||
|
|
0xCB,
|
||
|
|
0xBE,
|
||
|
|
0x39,
|
||
|
|
0x4A,
|
||
|
|
0x4C,
|
||
|
|
0x58,
|
||
|
|
0xCF,
|
||
|
|
0xD0,
|
||
|
|
0xEF,
|
||
|
|
0xAA,
|
||
|
|
0xFB,
|
||
|
|
0x43,
|
||
|
|
0x4D,
|
||
|
|
0x33,
|
||
|
|
0x85,
|
||
|
|
0x45,
|
||
|
|
0xF9,
|
||
|
|
0x02,
|
||
|
|
0x7F,
|
||
|
|
0x50,
|
||
|
|
0x3C,
|
||
|
|
0x9F,
|
||
|
|
0xA8,
|
||
|
|
0x51,
|
||
|
|
0xA3,
|
||
|
|
0x40,
|
||
|
|
0x8F,
|
||
|
|
0x92,
|
||
|
|
0x9D,
|
||
|
|
0x38,
|
||
|
|
0xF5,
|
||
|
|
0xBC,
|
||
|
|
0xB6,
|
||
|
|
0xDA,
|
||
|
|
0x21,
|
||
|
|
0x10,
|
||
|
|
0xFF,
|
||
|
|
0xF3,
|
||
|
|
0xD2,
|
||
|
|
0xCD,
|
||
|
|
0x0C,
|
||
|
|
0x13,
|
||
|
|
0xEC,
|
||
|
|
0x5F,
|
||
|
|
0x97,
|
||
|
|
0x44,
|
||
|
|
0x17,
|
||
|
|
0xC4,
|
||
|
|
0xA7,
|
||
|
|
0x7E,
|
||
|
|
0x3D,
|
||
|
|
0x64,
|
||
|
|
0x5D,
|
||
|
|
0x19,
|
||
|
|
0x73,
|
||
|
|
0x60,
|
||
|
|
0x81,
|
||
|
|
0x4F,
|
||
|
|
0xDC,
|
||
|
|
0x22,
|
||
|
|
0x2A,
|
||
|
|
0x90,
|
||
|
|
0x88,
|
||
|
|
0x46,
|
||
|
|
0xEE,
|
||
|
|
0xB8,
|
||
|
|
0x14,
|
||
|
|
0xDE,
|
||
|
|
0x5E,
|
||
|
|
0x0B,
|
||
|
|
0xDB,
|
||
|
|
0xE0,
|
||
|
|
0x32,
|
||
|
|
0x3A,
|
||
|
|
0x0A,
|
||
|
|
0x49,
|
||
|
|
0x06,
|
||
|
|
0x24,
|
||
|
|
0x5C,
|
||
|
|
0xC2,
|
||
|
|
0xD3,
|
||
|
|
0xAC,
|
||
|
|
0x62,
|
||
|
|
0x91,
|
||
|
|
0x95,
|
||
|
|
0xE4,
|
||
|
|
0x79,
|
||
|
|
0xE7,
|
||
|
|
0xC8,
|
||
|
|
0x37,
|
||
|
|
0x6D,
|
||
|
|
0x8D,
|
||
|
|
0xD5,
|
||
|
|
0x4E,
|
||
|
|
0xA9,
|
||
|
|
0x6C,
|
||
|
|
0x56,
|
||
|
|
0xF4,
|
||
|
|
0xEA,
|
||
|
|
0x65,
|
||
|
|
0x7A,
|
||
|
|
0xAE,
|
||
|
|
0x08,
|
||
|
|
0xBA,
|
||
|
|
0x78,
|
||
|
|
0x25,
|
||
|
|
0x2E,
|
||
|
|
0x1C,
|
||
|
|
0xA6,
|
||
|
|
0xB4,
|
||
|
|
0xC6,
|
||
|
|
0xE8,
|
||
|
|
0xDD,
|
||
|
|
0x74,
|
||
|
|
0x1F,
|
||
|
|
0x4B,
|
||
|
|
0xBD,
|
||
|
|
0x8B,
|
||
|
|
0x8A,
|
||
|
|
0x70,
|
||
|
|
0x3E,
|
||
|
|
0xB5,
|
||
|
|
0x66,
|
||
|
|
0x48,
|
||
|
|
0x03,
|
||
|
|
0xF6,
|
||
|
|
0x0E,
|
||
|
|
0x61,
|
||
|
|
0x35,
|
||
|
|
0x57,
|
||
|
|
0xB9,
|
||
|
|
0x86,
|
||
|
|
0xC1,
|
||
|
|
0x1D,
|
||
|
|
0x9E,
|
||
|
|
0xE1,
|
||
|
|
0xF8,
|
||
|
|
0x98,
|
||
|
|
0x11,
|
||
|
|
0x69,
|
||
|
|
0xD9,
|
||
|
|
0x8E,
|
||
|
|
0x94,
|
||
|
|
0x9B,
|
||
|
|
0x1E,
|
||
|
|
0x87,
|
||
|
|
0xE9,
|
||
|
|
0xCE,
|
||
|
|
0x55,
|
||
|
|
0x28,
|
||
|
|
0xDF,
|
||
|
|
0x8C,
|
||
|
|
0xA1,
|
||
|
|
0x89,
|
||
|
|
0x0D,
|
||
|
|
0xBF,
|
||
|
|
0xE6,
|
||
|
|
0x42,
|
||
|
|
0x68,
|
||
|
|
0x41,
|
||
|
|
0x99,
|
||
|
|
0x2D,
|
||
|
|
0x0F,
|
||
|
|
0xB0,
|
||
|
|
0x54,
|
||
|
|
0xBB,
|
||
|
|
0x16,
|
||
|
|
)
|
||
|
|
)
|
||
|
|
|
||
|
|
# multiplication of polynomials modulo x^8 + x^4 + x^3 + x + 1 = 0x11b
|
||
|
|
def aes_gf8_mul_2(x):
|
||
|
|
if x & 0x80:
|
||
|
|
return (x << 1) ^ 0x11B
|
||
|
|
else:
|
||
|
|
return x << 1
|
||
|
|
|
||
|
|
|
||
|
|
def aes_gf8_mul_3(x):
|
||
|
|
return x ^ aes_gf8_mul_2(x)
|
||
|
|
|
||
|
|
|
||
|
|
# non-linear, invertible, substitution box
|
||
|
|
def aes_s_box(a):
|
||
|
|
return aes_s_box_table[a & 0xFF]
|
||
|
|
|
||
|
|
|
||
|
|
# return 0x02^(a-1) in GF(2^8)
|
||
|
|
def aes_r_con(a):
|
||
|
|
ans = 1
|
||
|
|
while a > 1:
|
||
|
|
ans <<= 1
|
||
|
|
if ans & 0x100:
|
||
|
|
ans ^= 0x11B
|
||
|
|
a -= 1
|
||
|
|
return ans
|
||
|
|
|
||
|
|
|
||
|
|
##################################################################
|
||
|
|
# basic AES algorithm; see FIPS-197
|
||
|
|
|
||
|
|
# all inputs must be size 16
|
||
|
|
def aes_add_round_key(state, w):
|
||
|
|
for i in range(16):
|
||
|
|
state[i] ^= w[i]
|
||
|
|
|
||
|
|
|
||
|
|
# combined sub_bytes, shift_rows, mix_columns, add_round_key
|
||
|
|
# all inputs must be size 16
|
||
|
|
def aes_sb_sr_mc_ark(state, w, w_idx, temp):
|
||
|
|
temp_idx = 0
|
||
|
|
for i in range(4):
|
||
|
|
x0 = aes_s_box_table[state[i * 4]]
|
||
|
|
x1 = aes_s_box_table[state[1 + ((i + 1) & 3) * 4]]
|
||
|
|
x2 = aes_s_box_table[state[2 + ((i + 2) & 3) * 4]]
|
||
|
|
x3 = aes_s_box_table[state[3 + ((i + 3) & 3) * 4]]
|
||
|
|
temp[temp_idx] = aes_gf8_mul_2(x0) ^ aes_gf8_mul_3(x1) ^ x2 ^ x3 ^ w[w_idx]
|
||
|
|
temp[temp_idx + 1] = x0 ^ aes_gf8_mul_2(x1) ^ aes_gf8_mul_3(x2) ^ x3 ^ w[w_idx + 1]
|
||
|
|
temp[temp_idx + 2] = x0 ^ x1 ^ aes_gf8_mul_2(x2) ^ aes_gf8_mul_3(x3) ^ w[w_idx + 2]
|
||
|
|
temp[temp_idx + 3] = aes_gf8_mul_3(x0) ^ x1 ^ x2 ^ aes_gf8_mul_2(x3) ^ w[w_idx + 3]
|
||
|
|
w_idx += 4
|
||
|
|
temp_idx += 4
|
||
|
|
for i in range(16):
|
||
|
|
state[i] = temp[i]
|
||
|
|
|
||
|
|
|
||
|
|
# combined sub_bytes, shift_rows, add_round_key
|
||
|
|
# all inputs must be size 16
|
||
|
|
def aes_sb_sr_ark(state, w, w_idx, temp):
|
||
|
|
temp_idx = 0
|
||
|
|
for i in range(4):
|
||
|
|
x0 = aes_s_box_table[state[i * 4]]
|
||
|
|
x1 = aes_s_box_table[state[1 + ((i + 1) & 3) * 4]]
|
||
|
|
x2 = aes_s_box_table[state[2 + ((i + 2) & 3) * 4]]
|
||
|
|
x3 = aes_s_box_table[state[3 + ((i + 3) & 3) * 4]]
|
||
|
|
temp[temp_idx] = x0 ^ w[w_idx]
|
||
|
|
temp[temp_idx + 1] = x1 ^ w[w_idx + 1]
|
||
|
|
temp[temp_idx + 2] = x2 ^ w[w_idx + 2]
|
||
|
|
temp[temp_idx + 3] = x3 ^ w[w_idx + 3]
|
||
|
|
w_idx += 4
|
||
|
|
temp_idx += 4
|
||
|
|
for i in range(16):
|
||
|
|
state[i] = temp[i]
|
||
|
|
|
||
|
|
|
||
|
|
# take state as input and change it to the next state in the sequence
|
||
|
|
# state and temp have size 16, w has size 16 * (Nr + 1), Nr >= 1
|
||
|
|
def aes_state(state, w, temp, nr):
|
||
|
|
aes_add_round_key(state, w)
|
||
|
|
w_idx = 16
|
||
|
|
for i in range(nr - 1):
|
||
|
|
aes_sb_sr_mc_ark(state, w, w_idx, temp)
|
||
|
|
w_idx += 16
|
||
|
|
aes_sb_sr_ark(state, w, w_idx, temp)
|
||
|
|
|
||
|
|
|
||
|
|
# expand 'key' to 'w' for use with aes_state
|
||
|
|
# key has size 4 * Nk, w has size 16 * (Nr + 1), temp has size 16
|
||
|
|
def aes_key_expansion(key, w, temp, nk, nr):
|
||
|
|
for i in range(4 * nk):
|
||
|
|
w[i] = key[i]
|
||
|
|
w_idx = 4 * nk - 4
|
||
|
|
for i in range(nk, 4 * (nr + 1)):
|
||
|
|
t = temp
|
||
|
|
t_idx = 0
|
||
|
|
if i % nk == 0:
|
||
|
|
t[0] = aes_s_box(w[w_idx + 1]) ^ aes_r_con(i // nk)
|
||
|
|
for j in range(1, 4):
|
||
|
|
t[j] = aes_s_box(w[w_idx + (j + 1) % 4])
|
||
|
|
elif nk > 6 and i % nk == 4:
|
||
|
|
for j in range(0, 4):
|
||
|
|
t[j] = aes_s_box(w[w_idx + j])
|
||
|
|
else:
|
||
|
|
t = w
|
||
|
|
t_idx = w_idx
|
||
|
|
w_idx += 4
|
||
|
|
for j in range(4):
|
||
|
|
w[w_idx + j] = w[w_idx + j - 4 * nk] ^ t[t_idx + j]
|
||
|
|
|
||
|
|
|
||
|
|
##################################################################
|
||
|
|
# simple use of AES algorithm, using output feedback (OFB) mode
|
||
|
|
|
||
|
|
|
||
|
|
class AES:
|
||
|
|
def __init__(self, keysize):
|
||
|
|
if keysize == 128:
|
||
|
|
self.nk = 4
|
||
|
|
self.nr = 10
|
||
|
|
elif keysize == 192:
|
||
|
|
self.nk = 6
|
||
|
|
self.nr = 12
|
||
|
|
else:
|
||
|
|
assert keysize == 256
|
||
|
|
self.nk = 8
|
||
|
|
self.nr = 14
|
||
|
|
|
||
|
|
self.state = bytearray(16)
|
||
|
|
self.w = bytearray(16 * (self.nr + 1))
|
||
|
|
self.temp = bytearray(16)
|
||
|
|
self.state_pos = 16
|
||
|
|
|
||
|
|
def set_key(self, key):
|
||
|
|
aes_key_expansion(key, self.w, self.temp, self.nk, self.nr)
|
||
|
|
self.state_pos = 16
|
||
|
|
|
||
|
|
def set_iv(self, iv):
|
||
|
|
for i in range(16):
|
||
|
|
self.state[i] = iv[i]
|
||
|
|
self.state_pos = 16
|
||
|
|
|
||
|
|
def get_some_state(self, n_needed):
|
||
|
|
if self.state_pos >= 16:
|
||
|
|
aes_state(self.state, self.w, self.temp, self.nr)
|
||
|
|
self.state_pos = 0
|
||
|
|
n = 16 - self.state_pos
|
||
|
|
if n > n_needed:
|
||
|
|
n = n_needed
|
||
|
|
return n
|
||
|
|
|
||
|
|
def apply_to(self, data):
|
||
|
|
idx = 0
|
||
|
|
n = len(data)
|
||
|
|
while n > 0:
|
||
|
|
ln = self.get_some_state(n)
|
||
|
|
n -= ln
|
||
|
|
for i in range(ln):
|
||
|
|
data[idx + i] ^= self.state[self.state_pos + i]
|
||
|
|
idx += ln
|
||
|
|
self.state_pos += n
|
||
|
|
|
||
|
|
|
||
|
|
###########################################################################
|
||
|
|
# Benchmark interface
|
||
|
|
|
||
|
|
bm_params = {
|
||
|
|
(50, 25): (1, 16),
|
||
|
|
(100, 100): (1, 32),
|
||
|
|
(1000, 1000): (4, 256),
|
||
|
|
(5000, 1000): (20, 256),
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
def bm_setup(params):
|
||
|
|
nloop, datalen = params
|
||
|
|
|
||
|
|
aes = AES(256)
|
||
|
|
key = bytearray(256 // 8)
|
||
|
|
iv = bytearray(16)
|
||
|
|
data = bytearray(datalen)
|
||
|
|
# from now on we don't use the heap
|
||
|
|
|
||
|
|
def run():
|
||
|
|
for loop in range(nloop):
|
||
|
|
# encrypt
|
||
|
|
aes.set_key(key)
|
||
|
|
aes.set_iv(iv)
|
||
|
|
for i in range(2):
|
||
|
|
aes.apply_to(data)
|
||
|
|
|
||
|
|
# decrypt
|
||
|
|
aes.set_key(key)
|
||
|
|
aes.set_iv(iv)
|
||
|
|
for i in range(2):
|
||
|
|
aes.apply_to(data)
|
||
|
|
|
||
|
|
# verify
|
||
|
|
for i in range(len(data)):
|
||
|
|
assert data[i] == 0
|
||
|
|
|
||
|
|
def result():
|
||
|
|
return params[0] * params[1], True
|
||
|
|
|
||
|
|
return run, result
|