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Kovid Goyal 2016-03-21 21:39:57 +05:30
parent 186daa0417
commit 66e2fd598d
1 changed files with 26 additions and 40 deletions
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66
src/pyj/aes.pyj
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@ -158,63 +158,49 @@ class AES:
U3[(tt >> 8) & 0xFF] ^
U4[ tt & 0xFF])
def encrypt(self, plaintext, ciphertext, offset):
rounds = self._Ke.length - 1
def _crypt(self, plaintext, ciphertext, offset, encrypt):
if encrypt:
R1 = T1; R2 = T2; R3 = T3; R4 = T4
o1 = 1; o3 = 3
SB = S
K = self._Ke
else:
R1 = T5; R2 = T6; R3 = T7; R4 = T8
o1 = 3; o3 = 1
SB = Si
K = self._Kd
rounds = K.length - 1
a = self.working_mem[0]
t = self.working_mem[1]
# convert plaintext to (ints ^ key)
convert_to_int32(plaintext, t, offset, 16)
for v'var i = 0; i < 4; i++':
t[i] ^= self._Ke[0][i]
t[i] ^= K[0][i]
# apply round transforms
for v'var r = 1; r < rounds; r++':
for v'var i = 0; i < 4; i++':
a[i] = (T1[(t[i] >> 24) & 0xff] ^
T2[(t[(i + 1) % 4] >> 16) & 0xff] ^
T3[(t[(i + 2) % 4] >> 8) & 0xff] ^
T4[ t[(i + 3) % 4] & 0xff] ^
self._Ke[r][i])
a[i] = (R1[(t[i] >> 24) & 0xff] ^
R2[(t[(i + o1) % 4] >> 16) & 0xff] ^
R3[(t[(i + 2) % 4] >> 8) & 0xff] ^
R4[ t[(i + o3) % 4] & 0xff] ^
K[r][i])
t.set(a)
# the last round is special
for v'var i = 0; i < 4; i++':
tt = self._Ke[rounds][i]
ciphertext[offset + 4 * i] = (S[(t[i] >> 24) & 0xff] ^ (tt >> 24)) & 0xff
ciphertext[offset + 4 * i + 1] = (S[(t[(i + 1) % 4] >> 16) & 0xff] ^ (tt >> 16)) & 0xff
ciphertext[offset + 4 * i + 2] = (S[(t[(i + 2) % 4] >> 8) & 0xff] ^ (tt >> 8)) & 0xff
ciphertext[offset + 4 * i + 3] = (S[ t[(i + 3) % 4] & 0xff] ^ tt ) & 0xff
tt = K[rounds][i]
ciphertext[offset + 4 * i] = (SB[(t[i] >> 24) & 0xff] ^ (tt >> 24)) & 0xff
ciphertext[offset + 4 * i + 1] = (SB[(t[(i + o1) % 4] >> 16) & 0xff] ^ (tt >> 16)) & 0xff
ciphertext[offset + 4 * i + 2] = (SB[(t[(i + 2) % 4] >> 8) & 0xff] ^ (tt >> 8)) & 0xff
ciphertext[offset + 4 * i + 3] = (SB[ t[(i + o3) % 4] & 0xff] ^ tt ) & 0xff
def encrypt(self, plaintext, ciphertext, offset):
return self._crypt(plaintext, ciphertext, offset, True)
def decrypt(self, ciphertext, plaintext, offset):
rounds = self._Kd.length - 1
a = self.working_mem[0]
t = self.working_mem[1]
# convert plaintext to (ints ^ key)
convert_to_int32(ciphertext, t, offset, 16)
for v'var i = 0; i < 4; i++':
t[i] ^= self._Kd[0][i]
# apply round transforms
for v'var r = 1; r < rounds; r++':
for v'var i = 0; i < 4; i++':
a[i] = (T5[(t[i] >> 24) & 0xff] ^
T6[(t[(i + 3) % 4] >> 16) & 0xff] ^
T7[(t[(i + 2) % 4] >> 8) & 0xff] ^
T8[ t[(i + 1) % 4] & 0xff] ^
self._Kd[r][i])
t.set(a)
# the last round is special
for v'var i = 0; i < 4; i++':
tt = self._Kd[rounds][i]
plaintext[offset + 4 * i] = (Si[(t[ i ] >> 24) & 0xff] ^ (tt >> 24)) & 0xff
plaintext[offset + 4 * i + 1] = (Si[(t[(i + 3) % 4] >> 16) & 0xff] ^ (tt >> 16)) & 0xff
plaintext[offset + 4 * i + 2] = (Si[(t[(i + 2) % 4] >> 8) & 0xff] ^ (tt >> 8)) & 0xff
plaintext[offset + 4 * i + 3] = (Si[ t[(i + 1) % 4] & 0xff] ^ tt ) & 0xff
return self._crypt(ciphertext, plaintext, offset, False)
def random_bytes_insecure(sz):
ans = Uint8Array(sz)