1085 lines
24 KiB
C
1085 lines
24 KiB
C
/****************************************************************************
|
|
* crypto/aes.c
|
|
* $OpenBSD: aes.c,v 1.2 2020/07/22 13:54:30 tobhe Exp $
|
|
*
|
|
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
|
|
*
|
|
* Modified for OpenBSD by Thomas Pornin and Mike Belopuhov.
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining
|
|
* a copy of this software and associated documentation files (the
|
|
* "Software"), to deal in the Software without restriction, including
|
|
* without limitation the rights to use, copy, modify, merge, publish,
|
|
* distribute, sublicense, and/or sell copies of the Software, and to
|
|
* permit persons to whom the Software is furnished to do so, subject to
|
|
* the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be
|
|
* included in all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
|
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
|
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
|
|
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
|
|
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
|
|
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
* SOFTWARE.
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <string.h>
|
|
#include <sys/types.h>
|
|
#include <crypto/aes.h>
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
static inline void enc32le(FAR void *dst, uint32_t x)
|
|
{
|
|
FAR unsigned char *buf = dst;
|
|
|
|
buf[0] = (unsigned char)x;
|
|
buf[1] = (unsigned char)(x >> 8);
|
|
buf[2] = (unsigned char)(x >> 16);
|
|
buf[3] = (unsigned char)(x >> 24);
|
|
}
|
|
|
|
static inline uint32_t dec32le(FAR const void *src)
|
|
{
|
|
FAR const unsigned char *buf = src;
|
|
|
|
return (uint32_t)buf[0]
|
|
| ((uint32_t)buf[1] << 8)
|
|
| ((uint32_t)buf[2] << 16)
|
|
| ((uint32_t)buf[3] << 24);
|
|
}
|
|
|
|
/* This constant-time implementation is "bitsliced": the 128-bit state is
|
|
* split over eight 32-bit words q* in the following way:
|
|
*
|
|
* -- Input block consists in 16 bytes:
|
|
* a00 a10 a20 a30 a01 a11 a21 a31 a02 a12 a22 a32 a03 a13 a23 a33
|
|
* In the terminology of FIPS 197, this is a 4x4 matrix which is read
|
|
* column by column.
|
|
*
|
|
* -- Each byte is split into eight bits which are distributed over the
|
|
* eight words, at the same rank. Thus, for a byte x at rank k, bit 0
|
|
* (least significant) of x will be at rank k in q0 (if that bit is b,
|
|
* then it contributes "b << k" to the value of q0), bit 1 of x will be
|
|
* at rank k in q1, and so on.
|
|
*
|
|
* -- Ranks given to bits are in "row order" and are either all even, or
|
|
* all odd. Two independent AES states are thus interleaved, one using
|
|
* the even ranks, the other the odd ranks. Row order means:
|
|
* a00 a01 a02 a03 a10 a11 a12 a13 a20 a21 a22 a23 a30 a31 a32 a33
|
|
*
|
|
* Converting input bytes from two AES blocks to bitslice representation
|
|
* is done in the following way:
|
|
* -- Decode first block into the four words q0 q2 q4 q6, in that order,
|
|
* using little-endian convention.
|
|
* -- Decode second block into the four words q1 q3 q5 q7, in that order,
|
|
* using little-endian convention.
|
|
* -- Call aes_ct_ortho().
|
|
*
|
|
* Converting back to bytes is done by using the reverse operations. Note
|
|
* that aes_ct_ortho() is its own inverse.
|
|
*/
|
|
|
|
/* The AES S-box, as a bitsliced constant-time version. The input array
|
|
* consists in eight 32-bit words; 32 S-box instances are computed in
|
|
* parallel. Bits 0 to 7 of each S-box input (bit 0 is least significant)
|
|
* are spread over the words 0 to 7, at the same rank.
|
|
*/
|
|
|
|
static void aes_ct_bitslice_sbox(FAR uint32_t *q)
|
|
{
|
|
/* This S-box implementation is a straightforward translation of
|
|
* the circuit described by Boyar and Peralta in "A new
|
|
* combinational logic minimization technique with applications
|
|
* to cryptology" (https://eprint.iacr.org/2009/191.pdf).
|
|
*
|
|
* Note that variables x* (input) and s* (output) are numbered
|
|
* in "reverse" order (x0 is the high bit, x7 is the low bit).
|
|
*/
|
|
|
|
uint32_t x0;
|
|
uint32_t x1;
|
|
uint32_t x2;
|
|
uint32_t x3;
|
|
uint32_t x4;
|
|
uint32_t x5;
|
|
uint32_t x6;
|
|
uint32_t x7;
|
|
uint32_t y1;
|
|
uint32_t y2;
|
|
uint32_t y3;
|
|
uint32_t y4;
|
|
uint32_t y5;
|
|
uint32_t y6;
|
|
uint32_t y7;
|
|
uint32_t y8;
|
|
uint32_t y9;
|
|
uint32_t y10;
|
|
uint32_t y11;
|
|
uint32_t y12;
|
|
uint32_t y13;
|
|
uint32_t y14;
|
|
uint32_t y15;
|
|
uint32_t y16;
|
|
uint32_t y17;
|
|
uint32_t y18;
|
|
uint32_t y19;
|
|
uint32_t y20;
|
|
uint32_t y21;
|
|
uint32_t z0;
|
|
uint32_t z1;
|
|
uint32_t z2;
|
|
uint32_t z3;
|
|
uint32_t z4;
|
|
uint32_t z5;
|
|
uint32_t z6;
|
|
uint32_t z7;
|
|
uint32_t z8;
|
|
uint32_t z9;
|
|
uint32_t z10;
|
|
uint32_t z11;
|
|
uint32_t z12;
|
|
uint32_t z13;
|
|
uint32_t z14;
|
|
uint32_t z15;
|
|
uint32_t z16;
|
|
uint32_t z17;
|
|
uint32_t t0;
|
|
uint32_t t1;
|
|
uint32_t t2;
|
|
uint32_t t3;
|
|
uint32_t t4;
|
|
uint32_t t5;
|
|
uint32_t t6;
|
|
uint32_t t7;
|
|
uint32_t t8;
|
|
uint32_t t9;
|
|
uint32_t t10;
|
|
uint32_t t11;
|
|
uint32_t t12;
|
|
uint32_t t13;
|
|
uint32_t t14;
|
|
uint32_t t15;
|
|
uint32_t t16;
|
|
uint32_t t17;
|
|
uint32_t t18;
|
|
uint32_t t19;
|
|
uint32_t t20;
|
|
uint32_t t21;
|
|
uint32_t t22;
|
|
uint32_t t23;
|
|
uint32_t t24;
|
|
uint32_t t25;
|
|
uint32_t t26;
|
|
uint32_t t27;
|
|
uint32_t t28;
|
|
uint32_t t29;
|
|
uint32_t t30;
|
|
uint32_t t31;
|
|
uint32_t t32;
|
|
uint32_t t33;
|
|
uint32_t t34;
|
|
uint32_t t35;
|
|
uint32_t t36;
|
|
uint32_t t37;
|
|
uint32_t t38;
|
|
uint32_t t39;
|
|
uint32_t t40;
|
|
uint32_t t41;
|
|
uint32_t t42;
|
|
uint32_t t43;
|
|
uint32_t t44;
|
|
uint32_t t45;
|
|
uint32_t t46;
|
|
uint32_t t47;
|
|
uint32_t t48;
|
|
uint32_t t49;
|
|
uint32_t t50;
|
|
uint32_t t51;
|
|
uint32_t t52;
|
|
uint32_t t53;
|
|
uint32_t t54;
|
|
uint32_t t55;
|
|
uint32_t t56;
|
|
uint32_t t57;
|
|
uint32_t t58;
|
|
uint32_t t59;
|
|
uint32_t t60;
|
|
uint32_t t61;
|
|
uint32_t t62;
|
|
uint32_t t63;
|
|
uint32_t t64;
|
|
uint32_t t65;
|
|
uint32_t t66;
|
|
uint32_t t67;
|
|
uint32_t s0;
|
|
uint32_t s1;
|
|
uint32_t s2;
|
|
uint32_t s3;
|
|
uint32_t s4;
|
|
uint32_t s5;
|
|
uint32_t s6;
|
|
uint32_t s7;
|
|
|
|
x0 = q[7];
|
|
x1 = q[6];
|
|
x2 = q[5];
|
|
x3 = q[4];
|
|
x4 = q[3];
|
|
x5 = q[2];
|
|
x6 = q[1];
|
|
x7 = q[0];
|
|
|
|
/* Top linear transformation. */
|
|
|
|
y14 = x3 ^ x5;
|
|
y13 = x0 ^ x6;
|
|
y9 = x0 ^ x3;
|
|
y8 = x0 ^ x5;
|
|
t0 = x1 ^ x2;
|
|
y1 = t0 ^ x7;
|
|
y4 = y1 ^ x3;
|
|
y12 = y13 ^ y14;
|
|
y2 = y1 ^ x0;
|
|
y5 = y1 ^ x6;
|
|
y3 = y5 ^ y8;
|
|
t1 = x4 ^ y12;
|
|
y15 = t1 ^ x5;
|
|
y20 = t1 ^ x1;
|
|
y6 = y15 ^ x7;
|
|
y10 = y15 ^ t0;
|
|
y11 = y20 ^ y9;
|
|
y7 = x7 ^ y11;
|
|
y17 = y10 ^ y11;
|
|
y19 = y10 ^ y8;
|
|
y16 = t0 ^ y11;
|
|
y21 = y13 ^ y16;
|
|
y18 = x0 ^ y16;
|
|
|
|
/* Non-linear section. */
|
|
|
|
t2 = y12 & y15;
|
|
t3 = y3 & y6;
|
|
t4 = t3 ^ t2;
|
|
t5 = y4 & x7;
|
|
t6 = t5 ^ t2;
|
|
t7 = y13 & y16;
|
|
t8 = y5 & y1;
|
|
t9 = t8 ^ t7;
|
|
t10 = y2 & y7;
|
|
t11 = t10 ^ t7;
|
|
t12 = y9 & y11;
|
|
t13 = y14 & y17;
|
|
t14 = t13 ^ t12;
|
|
t15 = y8 & y10;
|
|
t16 = t15 ^ t12;
|
|
t17 = t4 ^ t14;
|
|
t18 = t6 ^ t16;
|
|
t19 = t9 ^ t14;
|
|
t20 = t11 ^ t16;
|
|
t21 = t17 ^ y20;
|
|
t22 = t18 ^ y19;
|
|
t23 = t19 ^ y21;
|
|
t24 = t20 ^ y18;
|
|
|
|
t25 = t21 ^ t22;
|
|
t26 = t21 & t23;
|
|
t27 = t24 ^ t26;
|
|
t28 = t25 & t27;
|
|
t29 = t28 ^ t22;
|
|
t30 = t23 ^ t24;
|
|
t31 = t22 ^ t26;
|
|
t32 = t31 & t30;
|
|
t33 = t32 ^ t24;
|
|
t34 = t23 ^ t33;
|
|
t35 = t27 ^ t33;
|
|
t36 = t24 & t35;
|
|
t37 = t36 ^ t34;
|
|
t38 = t27 ^ t36;
|
|
t39 = t29 & t38;
|
|
t40 = t25 ^ t39;
|
|
|
|
t41 = t40 ^ t37;
|
|
t42 = t29 ^ t33;
|
|
t43 = t29 ^ t40;
|
|
t44 = t33 ^ t37;
|
|
t45 = t42 ^ t41;
|
|
z0 = t44 & y15;
|
|
z1 = t37 & y6;
|
|
z2 = t33 & x7;
|
|
z3 = t43 & y16;
|
|
z4 = t40 & y1;
|
|
z5 = t29 & y7;
|
|
z6 = t42 & y11;
|
|
z7 = t45 & y17;
|
|
z8 = t41 & y10;
|
|
z9 = t44 & y12;
|
|
z10 = t37 & y3;
|
|
z11 = t33 & y4;
|
|
z12 = t43 & y13;
|
|
z13 = t40 & y5;
|
|
z14 = t29 & y2;
|
|
z15 = t42 & y9;
|
|
z16 = t45 & y14;
|
|
z17 = t41 & y8;
|
|
|
|
/* Bottom linear transformation. */
|
|
|
|
t46 = z15 ^ z16;
|
|
t47 = z10 ^ z11;
|
|
t48 = z5 ^ z13;
|
|
t49 = z9 ^ z10;
|
|
t50 = z2 ^ z12;
|
|
t51 = z2 ^ z5;
|
|
t52 = z7 ^ z8;
|
|
t53 = z0 ^ z3;
|
|
t54 = z6 ^ z7;
|
|
t55 = z16 ^ z17;
|
|
t56 = z12 ^ t48;
|
|
t57 = t50 ^ t53;
|
|
t58 = z4 ^ t46;
|
|
t59 = z3 ^ t54;
|
|
t60 = t46 ^ t57;
|
|
t61 = z14 ^ t57;
|
|
t62 = t52 ^ t58;
|
|
t63 = t49 ^ t58;
|
|
t64 = z4 ^ t59;
|
|
t65 = t61 ^ t62;
|
|
t66 = z1 ^ t63;
|
|
s0 = t59 ^ t63;
|
|
s6 = t56 ^ ~t62;
|
|
s7 = t48 ^ ~t60;
|
|
t67 = t64 ^ t65;
|
|
s3 = t53 ^ t66;
|
|
s4 = t51 ^ t66;
|
|
s5 = t47 ^ t65;
|
|
s1 = t64 ^ ~s3;
|
|
s2 = t55 ^ ~t67;
|
|
|
|
q[7] = s0;
|
|
q[6] = s1;
|
|
q[5] = s2;
|
|
q[4] = s3;
|
|
q[3] = s4;
|
|
q[2] = s5;
|
|
q[1] = s6;
|
|
q[0] = s7;
|
|
}
|
|
|
|
/* Perform bytewise orthogonalization of eight 32-bit words. Bytes
|
|
* of q0..q7 are spread over all words: for a byte x that occurs
|
|
* at rank i in q[j] (byte x uses bits 8*i to 8*i+7 in q[j]), the bit
|
|
* of rank k in x (0 <= k <= 7) goes to q[k] at rank 8*i+j.
|
|
*
|
|
* This operation is an involution.
|
|
*/
|
|
|
|
static void aes_ct_ortho(FAR uint32_t *q)
|
|
{
|
|
#define SWAPN(cl, ch, s, x, y) do { \
|
|
uint32_t a, b; \
|
|
a = (x); \
|
|
b = (y); \
|
|
(x) = (a & (uint32_t)cl) | ((b & (uint32_t)cl) << (s)); \
|
|
(y) = ((a & (uint32_t)ch) >> (s)) | (b & (uint32_t)ch); \
|
|
} while (0)
|
|
|
|
#define SWAP2(x, y) SWAPN(0x55555555, 0xaaaaaaaa, 1, x, y)
|
|
#define SWAP4(x, y) SWAPN(0x33333333, 0xcccccccc, 2, x, y)
|
|
#define SWAP8(x, y) SWAPN(0x0f0f0f0f, 0xf0f0f0f0, 4, x, y)
|
|
|
|
SWAP2(q[0], q[1]);
|
|
SWAP2(q[2], q[3]);
|
|
SWAP2(q[4], q[5]);
|
|
SWAP2(q[6], q[7]);
|
|
|
|
SWAP4(q[0], q[2]);
|
|
SWAP4(q[1], q[3]);
|
|
SWAP4(q[4], q[6]);
|
|
SWAP4(q[5], q[7]);
|
|
|
|
SWAP8(q[0], q[4]);
|
|
SWAP8(q[1], q[5]);
|
|
SWAP8(q[2], q[6]);
|
|
SWAP8(q[3], q[7]);
|
|
}
|
|
|
|
static inline uint32_t sub_word(uint32_t x)
|
|
{
|
|
uint32_t q[8];
|
|
int i;
|
|
|
|
for (i = 0; i < 8; i++)
|
|
{
|
|
q[i] = x;
|
|
}
|
|
|
|
aes_ct_ortho(q);
|
|
aes_ct_bitslice_sbox(q);
|
|
aes_ct_ortho(q);
|
|
return q[0];
|
|
}
|
|
|
|
static const unsigned char rcon[] =
|
|
{
|
|
0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
|
|
};
|
|
|
|
/* Base key schedule code. The function sub_word() must be defined
|
|
* below. Subkeys are produced in little-endian convention (but not
|
|
* bitsliced). Key length is expressed in bytes.
|
|
*/
|
|
|
|
static unsigned aes_keysched_base(FAR uint32_t *skey,
|
|
FAR const void *key, size_t key_len)
|
|
{
|
|
unsigned num_rounds;
|
|
int i;
|
|
int j;
|
|
int k;
|
|
int nk;
|
|
int nkf;
|
|
uint32_t tmp;
|
|
|
|
switch (key_len)
|
|
{
|
|
case 16:
|
|
num_rounds = 10;
|
|
break;
|
|
case 24:
|
|
num_rounds = 12;
|
|
break;
|
|
case 32:
|
|
num_rounds = 14;
|
|
break;
|
|
default:
|
|
return 0;
|
|
}
|
|
|
|
nk = (int)(key_len >> 2);
|
|
nkf = (int)((num_rounds + 1) << 2);
|
|
for (i = 0; i < nk; i++)
|
|
{
|
|
tmp = dec32le((FAR const unsigned char *)key + (i << 2));
|
|
skey[i] = tmp;
|
|
}
|
|
|
|
tmp = skey[(key_len >> 2) - 1];
|
|
for (i = nk, j = 0, k = 0; i < nkf; i++)
|
|
{
|
|
if (j == 0)
|
|
{
|
|
tmp = (tmp << 24) | (tmp >> 8);
|
|
tmp = sub_word(tmp) ^ rcon[k];
|
|
}
|
|
else if (nk > 6 && j == 4)
|
|
{
|
|
tmp = sub_word(tmp);
|
|
}
|
|
|
|
tmp ^= skey[i - nk];
|
|
skey[i] = tmp;
|
|
if (++j == nk)
|
|
{
|
|
j = 0;
|
|
k++;
|
|
}
|
|
}
|
|
|
|
return num_rounds;
|
|
}
|
|
|
|
/* AES key schedule, constant-time version. skey[] is filled with n+1
|
|
* 128-bit subkeys, where n is the number of rounds (10 to 14, depending
|
|
* on key size). The number of rounds is returned. If the key size is
|
|
* invalid (not 16, 24 or 32), then 0 is returned.
|
|
*/
|
|
|
|
unsigned aes_ct_keysched(FAR uint32_t *comp_skey,
|
|
FAR const void *key,
|
|
size_t key_len)
|
|
{
|
|
uint32_t skey[60];
|
|
unsigned u;
|
|
unsigned num_rounds;
|
|
|
|
num_rounds = aes_keysched_base(skey, key, key_len);
|
|
for (u = 0; u <= num_rounds; u++)
|
|
{
|
|
uint32_t q[8];
|
|
|
|
q[0] = q[1] = skey[(u << 2) + 0];
|
|
q[2] = q[3] = skey[(u << 2) + 1];
|
|
q[4] = q[5] = skey[(u << 2) + 2];
|
|
q[6] = q[7] = skey[(u << 2) + 3];
|
|
aes_ct_ortho(q);
|
|
comp_skey[(u << 2) + 0] =
|
|
(q[0] & 0x55555555) | (q[1] & 0xaaaaaaaa);
|
|
comp_skey[(u << 2) + 1] =
|
|
(q[2] & 0x55555555) | (q[3] & 0xaaaaaaaa);
|
|
comp_skey[(u << 2) + 2] =
|
|
(q[4] & 0x55555555) | (q[5] & 0xaaaaaaaa);
|
|
comp_skey[(u << 2) + 3] =
|
|
(q[6] & 0x55555555) | (q[7] & 0xaaaaaaaa);
|
|
}
|
|
|
|
return num_rounds;
|
|
}
|
|
|
|
/* Expand AES subkeys as produced by aes_ct_keysched(), into
|
|
* a larger array suitable for aes_ct_bitslice_encrypt() and
|
|
* aes_ct_bitslice_decrypt().
|
|
*/
|
|
|
|
void aes_ct_skey_expand(FAR uint32_t *skey,
|
|
unsigned num_rounds,
|
|
FAR const uint32_t *comp_skey)
|
|
{
|
|
unsigned u;
|
|
unsigned v;
|
|
unsigned n;
|
|
|
|
n = (num_rounds + 1) << 2;
|
|
for (u = 0, v = 0; u < n; u ++, v += 2)
|
|
{
|
|
uint32_t x;
|
|
uint32_t y;
|
|
|
|
x = y = comp_skey[u];
|
|
x &= 0x55555555;
|
|
skey[v + 0] = x | (x << 1);
|
|
y &= 0xaaaaaaaa;
|
|
skey[v + 1] = y | (y >> 1);
|
|
}
|
|
}
|
|
|
|
static inline void add_round_key(FAR uint32_t *q, FAR const uint32_t *sk)
|
|
{
|
|
q[0] ^= sk[0];
|
|
q[1] ^= sk[1];
|
|
q[2] ^= sk[2];
|
|
q[3] ^= sk[3];
|
|
q[4] ^= sk[4];
|
|
q[5] ^= sk[5];
|
|
q[6] ^= sk[6];
|
|
q[7] ^= sk[7];
|
|
}
|
|
|
|
static inline void shift_rows(FAR uint32_t *q)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 8; i++)
|
|
{
|
|
uint32_t x;
|
|
|
|
x = q[i];
|
|
q[i] = (x & 0x000000ff)
|
|
| ((x & 0x0000fc00) >> 2) | ((x & 0x00000300) << 6)
|
|
| ((x & 0x00f00000) >> 4) | ((x & 0x000f0000) << 4)
|
|
| ((x & 0xc0000000) >> 6) | ((x & 0x3f000000) << 2);
|
|
}
|
|
}
|
|
|
|
static inline uint32_t rotr16(uint32_t x)
|
|
{
|
|
return (x << 16) | (x >> 16);
|
|
}
|
|
|
|
static inline void mix_columns(FAR uint32_t *q)
|
|
{
|
|
uint32_t q0;
|
|
uint32_t q1;
|
|
uint32_t q2;
|
|
uint32_t q3;
|
|
uint32_t q4;
|
|
uint32_t q5;
|
|
uint32_t q6;
|
|
uint32_t q7;
|
|
uint32_t r0;
|
|
uint32_t r1;
|
|
uint32_t r2;
|
|
uint32_t r3;
|
|
uint32_t r4;
|
|
uint32_t r5;
|
|
uint32_t r6;
|
|
uint32_t r7;
|
|
|
|
q0 = q[0];
|
|
q1 = q[1];
|
|
q2 = q[2];
|
|
q3 = q[3];
|
|
q4 = q[4];
|
|
q5 = q[5];
|
|
q6 = q[6];
|
|
q7 = q[7];
|
|
r0 = (q0 >> 8) | (q0 << 24);
|
|
r1 = (q1 >> 8) | (q1 << 24);
|
|
r2 = (q2 >> 8) | (q2 << 24);
|
|
r3 = (q3 >> 8) | (q3 << 24);
|
|
r4 = (q4 >> 8) | (q4 << 24);
|
|
r5 = (q5 >> 8) | (q5 << 24);
|
|
r6 = (q6 >> 8) | (q6 << 24);
|
|
r7 = (q7 >> 8) | (q7 << 24);
|
|
|
|
q[0] = q7 ^ r7 ^ r0 ^ rotr16(q0 ^ r0);
|
|
q[1] = q0 ^ r0 ^ q7 ^ r7 ^ r1 ^ rotr16(q1 ^ r1);
|
|
q[2] = q1 ^ r1 ^ r2 ^ rotr16(q2 ^ r2);
|
|
q[3] = q2 ^ r2 ^ q7 ^ r7 ^ r3 ^ rotr16(q3 ^ r3);
|
|
q[4] = q3 ^ r3 ^ q7 ^ r7 ^ r4 ^ rotr16(q4 ^ r4);
|
|
q[5] = q4 ^ r4 ^ r5 ^ rotr16(q5 ^ r5);
|
|
q[6] = q5 ^ r5 ^ r6 ^ rotr16(q6 ^ r6);
|
|
q[7] = q6 ^ r6 ^ r7 ^ rotr16(q7 ^ r7);
|
|
}
|
|
|
|
/* Compute AES encryption on bitsliced data. Since input is stored on
|
|
* eight 32-bit words, two block encryptions are actually performed
|
|
* in parallel.
|
|
*/
|
|
|
|
void aes_ct_bitslice_encrypt(unsigned num_rounds,
|
|
FAR const uint32_t *skey,
|
|
FAR uint32_t *q)
|
|
{
|
|
unsigned u;
|
|
|
|
add_round_key(q, skey);
|
|
for (u = 1; u < num_rounds; u++)
|
|
{
|
|
aes_ct_bitslice_sbox(q);
|
|
shift_rows(q);
|
|
mix_columns(q);
|
|
add_round_key(q, skey + (u << 3));
|
|
}
|
|
|
|
aes_ct_bitslice_sbox(q);
|
|
shift_rows(q);
|
|
add_round_key(q, skey + (num_rounds << 3));
|
|
}
|
|
|
|
/* Like aes_ct_bitslice_sbox(), but for the inverse S-box. */
|
|
|
|
void aes_ct_bitslice_invsbox(FAR uint32_t *q)
|
|
{
|
|
/* AES S-box is:
|
|
* S(x) = A(I(x)) ^ 0x63
|
|
* where I() is inversion in GF(256), and A() is a linear
|
|
* transform (0 is formally defined to be its own inverse).
|
|
* Since inversion is an involution, the inverse S-box can be
|
|
* computed from the S-box as:
|
|
* iS(x) = B(S(B(x ^ 0x63)) ^ 0x63)
|
|
* where B() is the inverse of A(). Indeed, for any y in GF(256):
|
|
* iS(S(y)) = B(A(I(B(A(I(y)) ^ 0x63 ^ 0x63))) ^ 0x63 ^ 0x63) = y
|
|
*
|
|
* Note: we reuse the implementation of the forward S-box,
|
|
* instead of duplicating it here, so that total code size is
|
|
* lower. By merging the B() transforms into the S-box circuit
|
|
* we could make faster CBC decryption, but CBC decryption is
|
|
* already quite faster than CBC encryption because we can
|
|
* process two blocks in parallel.
|
|
*/
|
|
|
|
uint32_t q0;
|
|
uint32_t q1;
|
|
uint32_t q2;
|
|
uint32_t q3;
|
|
uint32_t q4;
|
|
uint32_t q5;
|
|
uint32_t q6;
|
|
uint32_t q7;
|
|
|
|
q0 = ~q[0];
|
|
q1 = ~q[1];
|
|
q2 = q[2];
|
|
q3 = q[3];
|
|
q4 = q[4];
|
|
q5 = ~q[5];
|
|
q6 = ~q[6];
|
|
q7 = q[7];
|
|
q[7] = q1 ^ q4 ^ q6;
|
|
q[6] = q0 ^ q3 ^ q5;
|
|
q[5] = q7 ^ q2 ^ q4;
|
|
q[4] = q6 ^ q1 ^ q3;
|
|
q[3] = q5 ^ q0 ^ q2;
|
|
q[2] = q4 ^ q7 ^ q1;
|
|
q[1] = q3 ^ q6 ^ q0;
|
|
q[0] = q2 ^ q5 ^ q7;
|
|
|
|
aes_ct_bitslice_sbox(q);
|
|
|
|
q0 = ~q[0];
|
|
q1 = ~q[1];
|
|
q2 = q[2];
|
|
q3 = q[3];
|
|
q4 = q[4];
|
|
q5 = ~q[5];
|
|
q6 = ~q[6];
|
|
q7 = q[7];
|
|
q[7] = q1 ^ q4 ^ q6;
|
|
q[6] = q0 ^ q3 ^ q5;
|
|
q[5] = q7 ^ q2 ^ q4;
|
|
q[4] = q6 ^ q1 ^ q3;
|
|
q[3] = q5 ^ q0 ^ q2;
|
|
q[2] = q4 ^ q7 ^ q1;
|
|
q[1] = q3 ^ q6 ^ q0;
|
|
q[0] = q2 ^ q5 ^ q7;
|
|
}
|
|
|
|
static inline void inv_shift_rows(FAR uint32_t *q)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 8; i++)
|
|
{
|
|
uint32_t x;
|
|
|
|
x = q[i];
|
|
q[i] = (x & 0x000000ff)
|
|
| ((x & 0x00003f00) << 2) | ((x & 0x0000c000) >> 6)
|
|
| ((x & 0x000f0000) << 4) | ((x & 0x00f00000) >> 4)
|
|
| ((x & 0x03000000) << 6) | ((x & 0xfc000000) >> 2);
|
|
}
|
|
}
|
|
|
|
static void inv_mix_columns(FAR uint32_t *q)
|
|
{
|
|
uint32_t q0;
|
|
uint32_t q1;
|
|
uint32_t q2;
|
|
uint32_t q3;
|
|
uint32_t q4;
|
|
uint32_t q5;
|
|
uint32_t q6;
|
|
uint32_t q7;
|
|
uint32_t r0;
|
|
uint32_t r1;
|
|
uint32_t r2;
|
|
uint32_t r3;
|
|
uint32_t r4;
|
|
uint32_t r5;
|
|
uint32_t r6;
|
|
uint32_t r7;
|
|
|
|
q0 = q[0];
|
|
q1 = q[1];
|
|
q2 = q[2];
|
|
q3 = q[3];
|
|
q4 = q[4];
|
|
q5 = q[5];
|
|
q6 = q[6];
|
|
q7 = q[7];
|
|
r0 = (q0 >> 8) | (q0 << 24);
|
|
r1 = (q1 >> 8) | (q1 << 24);
|
|
r2 = (q2 >> 8) | (q2 << 24);
|
|
r3 = (q3 >> 8) | (q3 << 24);
|
|
r4 = (q4 >> 8) | (q4 << 24);
|
|
r5 = (q5 >> 8) | (q5 << 24);
|
|
r6 = (q6 >> 8) | (q6 << 24);
|
|
r7 = (q7 >> 8) | (q7 << 24);
|
|
|
|
q[0] = q5 ^ q6 ^ q7 ^ r0 ^ r5 ^
|
|
r7 ^ rotr16(q0 ^ q5 ^ q6 ^ r0 ^ r5);
|
|
|
|
q[1] = q0 ^ q5 ^ r0 ^ r1 ^ r5 ^
|
|
r6 ^ r7 ^ rotr16(q1 ^ q5 ^ q7 ^ r1 ^ r5 ^ r6);
|
|
|
|
q[2] = q0 ^ q1 ^ q6 ^ r1 ^ r2 ^
|
|
r6 ^ r7 ^ rotr16(q0 ^ q2 ^ q6 ^ r2 ^ r6 ^ r7);
|
|
|
|
q[3] = q0 ^ q1 ^ q2 ^ q5 ^ q6 ^
|
|
r0 ^ r2 ^ r3 ^ r5 ^
|
|
rotr16(q0 ^ q1 ^ q3 ^ q5 ^ q6 ^ q7 ^ r0 ^ r3 ^ r5 ^ r7);
|
|
|
|
q[4] = q1 ^ q2 ^ q3 ^ q5 ^ r1 ^
|
|
r3 ^ r4 ^ r5 ^ r6 ^ r7 ^
|
|
rotr16(q1 ^ q2 ^ q4 ^ q5 ^ q7 ^ r1 ^ r4 ^ r5 ^ r6);
|
|
|
|
q[5] = q2 ^ q3 ^ q4 ^ q6 ^ r2 ^
|
|
r4 ^ r5 ^ r6 ^ r7 ^
|
|
rotr16(q2 ^ q3 ^ q5 ^ q6 ^ r2 ^ r5 ^ r6 ^ r7);
|
|
|
|
q[6] = q3 ^ q4 ^ q5 ^ q7 ^ r3 ^
|
|
r5 ^ r6 ^ r7 ^
|
|
rotr16(q3 ^ q4 ^ q6 ^ q7 ^ r3 ^ r6 ^ r7);
|
|
|
|
q[7] = q4 ^ q5 ^ q6 ^ r4 ^ r6 ^
|
|
r7 ^ rotr16(q4 ^ q5 ^ q7 ^ r4 ^ r7);
|
|
}
|
|
|
|
/* Compute AES decryption on bitsliced data.
|
|
* Since input is stored on
|
|
* eight 32-bit words, two block decryptions
|
|
* are actually performed in parallel.
|
|
*/
|
|
|
|
void aes_ct_bitslice_decrypt(unsigned num_rounds,
|
|
FAR const uint32_t *skey,
|
|
FAR uint32_t *q)
|
|
{
|
|
unsigned u;
|
|
|
|
add_round_key(q, skey + (num_rounds << 3));
|
|
for (u = num_rounds - 1; u > 0; u--)
|
|
{
|
|
inv_shift_rows(q);
|
|
aes_ct_bitslice_invsbox(q);
|
|
add_round_key(q, skey + (u << 3));
|
|
inv_mix_columns(q);
|
|
}
|
|
|
|
inv_shift_rows(q);
|
|
aes_ct_bitslice_invsbox(q);
|
|
add_round_key(q, skey);
|
|
}
|
|
|
|
int aes_setkey(FAR AES_CTX *ctx, FAR const uint8_t *key, int len)
|
|
{
|
|
ctx->num_rounds = aes_ct_keysched(ctx->sk, key, len);
|
|
if (ctx->num_rounds == 0)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
aes_ct_skey_expand(ctx->sk_exp, ctx->num_rounds, ctx->sk);
|
|
return 0;
|
|
}
|
|
|
|
void aes_encrypt_ecb(FAR AES_CTX *ctx, FAR const uint8_t *src,
|
|
FAR uint8_t *dst, size_t num_blocks)
|
|
{
|
|
while (num_blocks > 0)
|
|
{
|
|
uint32_t q[8];
|
|
|
|
q[0] = dec32le(src);
|
|
q[2] = dec32le(src + 4);
|
|
q[4] = dec32le(src + 8);
|
|
q[6] = dec32le(src + 12);
|
|
if (num_blocks > 1)
|
|
{
|
|
q[1] = dec32le(src + 16);
|
|
q[3] = dec32le(src + 20);
|
|
q[5] = dec32le(src + 24);
|
|
q[7] = dec32le(src + 28);
|
|
}
|
|
else
|
|
{
|
|
q[1] = 0;
|
|
q[3] = 0;
|
|
q[5] = 0;
|
|
q[7] = 0;
|
|
}
|
|
|
|
aes_ct_ortho(q);
|
|
aes_ct_bitslice_encrypt(ctx->num_rounds, ctx->sk_exp, q);
|
|
aes_ct_ortho(q);
|
|
enc32le(dst, q[0]);
|
|
enc32le(dst + 4, q[2]);
|
|
enc32le(dst + 8, q[4]);
|
|
enc32le(dst + 12, q[6]);
|
|
if (num_blocks > 1)
|
|
{
|
|
enc32le(dst + 16, q[1]);
|
|
enc32le(dst + 20, q[3]);
|
|
enc32le(dst + 24, q[5]);
|
|
enc32le(dst + 28, q[7]);
|
|
src += 32;
|
|
dst += 32;
|
|
num_blocks -= 2;
|
|
}
|
|
else
|
|
{
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void aes_decrypt_ecb(FAR AES_CTX *ctx, FAR const uint8_t *src,
|
|
FAR uint8_t *dst, size_t num_blocks)
|
|
{
|
|
while (num_blocks > 0)
|
|
{
|
|
uint32_t q[8];
|
|
|
|
q[0] = dec32le(src);
|
|
q[2] = dec32le(src + 4);
|
|
q[4] = dec32le(src + 8);
|
|
q[6] = dec32le(src + 12);
|
|
if (num_blocks > 1)
|
|
{
|
|
q[1] = dec32le(src + 16);
|
|
q[3] = dec32le(src + 20);
|
|
q[5] = dec32le(src + 24);
|
|
q[7] = dec32le(src + 28);
|
|
}
|
|
else
|
|
{
|
|
q[1] = 0;
|
|
q[3] = 0;
|
|
q[5] = 0;
|
|
q[7] = 0;
|
|
}
|
|
|
|
aes_ct_ortho(q);
|
|
aes_ct_bitslice_decrypt(ctx->num_rounds, ctx->sk_exp, q);
|
|
aes_ct_ortho(q);
|
|
enc32le(dst, q[0]);
|
|
enc32le(dst + 4, q[2]);
|
|
enc32le(dst + 8, q[4]);
|
|
enc32le(dst + 12, q[6]);
|
|
if (num_blocks > 1)
|
|
{
|
|
enc32le(dst + 16, q[1]);
|
|
enc32le(dst + 20, q[3]);
|
|
enc32le(dst + 24, q[5]);
|
|
enc32le(dst + 28, q[7]);
|
|
src += 32;
|
|
dst += 32;
|
|
num_blocks -= 2;
|
|
}
|
|
else
|
|
{
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void aes_encrypt(FAR AES_CTX *ctx, FAR const uint8_t *src, FAR uint8_t *dst)
|
|
{
|
|
aes_encrypt_ecb(ctx, src, dst, 1);
|
|
}
|
|
|
|
void aes_decrypt(FAR AES_CTX *ctx, FAR const uint8_t *src, FAR uint8_t *dst)
|
|
{
|
|
aes_decrypt_ecb(ctx, src, dst, 1);
|
|
}
|
|
|
|
int aes_keysetup_encrypt(FAR uint32_t *skey, FAR const uint8_t *key, int len)
|
|
{
|
|
unsigned r;
|
|
unsigned u;
|
|
uint32_t tkey[60];
|
|
|
|
r = aes_keysched_base(tkey, key, len);
|
|
if (r == 0)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
for (u = 0; u < ((r + 1) << 2); u++)
|
|
{
|
|
uint32_t w;
|
|
|
|
w = tkey[u];
|
|
skey[u] = (w << 24)
|
|
| ((w & 0x0000ff00) << 8)
|
|
| ((w & 0x00ff0000) >> 8)
|
|
| (w >> 24);
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
/* Reduce value x modulo polynomial x^8+x^4+x^3+x+1. This works as
|
|
* long as x fits on 12 bits at most.
|
|
*/
|
|
|
|
static inline uint32_t redgf256(uint32_t x)
|
|
{
|
|
uint32_t h;
|
|
|
|
h = x >> 8;
|
|
return (x ^ h ^ (h << 1) ^ (h << 3) ^ (h << 4)) & 0xff;
|
|
}
|
|
|
|
/* Multiplication by 0x09 in GF(256). */
|
|
|
|
static inline uint32_t mul9(uint32_t x)
|
|
{
|
|
return redgf256(x ^ (x << 3));
|
|
}
|
|
|
|
/* Multiplication by 0x0B in GF(256). */
|
|
|
|
static inline uint32_t mulb(uint32_t x)
|
|
{
|
|
return redgf256(x ^ (x << 1) ^ (x << 3));
|
|
}
|
|
|
|
/* Multiplication by 0x0D in GF(256). */
|
|
|
|
static inline uint32_t muld(uint32_t x)
|
|
{
|
|
return redgf256(x ^ (x << 2) ^ (x << 3));
|
|
}
|
|
|
|
/* Multiplication by 0x0E in GF(256). */
|
|
|
|
static inline uint32_t mule(uint32_t x)
|
|
{
|
|
return redgf256((x << 1) ^ (x << 2) ^ (x << 3));
|
|
}
|
|
|
|
int aes_keysetup_decrypt(FAR uint32_t *skey,
|
|
FAR const uint8_t *key,
|
|
int len)
|
|
{
|
|
unsigned r;
|
|
unsigned u;
|
|
uint32_t tkey[60];
|
|
|
|
/* Compute encryption subkeys. We get them in big-endian
|
|
* notation.
|
|
*/
|
|
|
|
r = aes_keysetup_encrypt(tkey, key, len);
|
|
if (r == 0)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
/* Copy the subkeys in reverse order. Also, apply InvMixColumns()
|
|
* on the subkeys (except first and last).
|
|
*/
|
|
|
|
memcpy(skey + (r << 2), tkey, 4 * sizeof(uint32_t));
|
|
memcpy(skey, tkey + (r << 2), 4 * sizeof(uint32_t));
|
|
for (u = 4; u < (r << 2); u++)
|
|
{
|
|
uint32_t sk;
|
|
uint32_t sk0;
|
|
uint32_t sk1;
|
|
uint32_t sk2;
|
|
uint32_t sk3;
|
|
uint32_t tk;
|
|
uint32_t tk0;
|
|
uint32_t tk1;
|
|
uint32_t tk2;
|
|
uint32_t tk3;
|
|
|
|
sk = tkey[u];
|
|
sk0 = sk >> 24;
|
|
sk1 = (sk >> 16) & 0xff;
|
|
sk2 = (sk >> 8) & 0xff;
|
|
sk3 = sk & 0xff;
|
|
tk0 = mule(sk0) ^ mulb(sk1) ^ muld(sk2) ^ mul9(sk3);
|
|
tk1 = mul9(sk0) ^ mule(sk1) ^ mulb(sk2) ^ muld(sk3);
|
|
tk2 = muld(sk0) ^ mul9(sk1) ^ mule(sk2) ^ mulb(sk3);
|
|
tk3 = mulb(sk0) ^ muld(sk1) ^ mul9(sk2) ^ mule(sk3);
|
|
tk = (tk0 << 24) ^ (tk1 << 16) ^ (tk2 << 8) ^ tk3;
|
|
skey[((r - (u >> 2)) << 2) + (u & 3)] = tk;
|
|
}
|
|
|
|
return r;
|
|
}
|