/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* 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.
*/
#include "inner.h"
/*
* During key schedule, we need to apply bit extraction PC-2 then permute
* things into our bitslice representation. PC-2 extracts 48 bits out
* of two 28-bit words (kl and kr), and we store these bits into two
* 32-bit words sk0 and sk1.
*
* -- bit 16+x of sk0 comes from bit QL0[x] of kl
* -- bit x of sk0 comes from bit QR0[x] of kr
* -- bit 16+x of sk1 comes from bit QL1[x] of kl
* -- bit x of sk1 comes from bit QR1[x] of kr
*/
static const unsigned char QL0[] = {
17, 4, 27, 23, 13, 22, 7, 18,
16, 24, 2, 20, 1, 8, 15, 26
};
static const unsigned char QR0[] = {
25, 19, 9, 1, 5, 11, 23, 8,
17, 0, 22, 3, 6, 20, 27, 24
};
static const unsigned char QL1[] = {
28, 28, 14, 11, 28, 28, 25, 0,
28, 28, 5, 9, 28, 28, 12, 21
};
static const unsigned char QR1[] = {
28, 28, 15, 4, 28, 28, 26, 16,
28, 28, 12, 7, 28, 28, 10, 14
};
/*
* 32-bit rotation. The C compiler is supposed to recognize it as a
* rotation and use the local architecture rotation opcode (if available).
*/
static inline uint32_t
rotl(uint32_t x, int n)
{
return (x << n) | (x >> (32 - n));
}
/*
* Compute key schedule for 8 key bytes (produces 32 subkey words).
*/
static void
keysched_unit(uint32_t *skey, const void *key)
{
int i;
br_des_keysched_unit(skey, key);
/*
* Apply PC-2 + bitslicing.
*/
for (i = 0; i < 16; i ++) {
uint32_t kl, kr, sk0, sk1;
int j;
kl = skey[(i << 1) + 0];
kr = skey[(i << 1) + 1];
sk0 = 0;
sk1 = 0;
for (j = 0; j < 16; j ++) {
sk0 <<= 1;
sk1 <<= 1;
sk0 |= ((kl >> QL0[j]) & (uint32_t)1) << 16;
sk0 |= (kr >> QR0[j]) & (uint32_t)1;
sk1 |= ((kl >> QL1[j]) & (uint32_t)1) << 16;
sk1 |= (kr >> QR1[j]) & (uint32_t)1;
}
skey[(i << 1) + 0] = sk0;
skey[(i << 1) + 1] = sk1;
}
#if 0
/*
* Speed-optimized version for PC-2 + bitslicing.
* (Unused. Kept for reference only.)
*/
sk0 = kl & (uint32_t)0x00100000;
sk0 |= (kl & (uint32_t)0x08008000) << 2;
sk0 |= (kl & (uint32_t)0x00400000) << 4;
sk0 |= (kl & (uint32_t)0x00800000) << 5;
sk0 |= (kl & (uint32_t)0x00040000) << 6;
sk0 |= (kl & (uint32_t)0x00010000) << 7;
sk0 |= (kl & (uint32_t)0x00000100) << 10;
sk0 |= (kl & (uint32_t)0x00022000) << 14;
sk0 |= (kl & (uint32_t)0x00000082) << 18;
sk0 |= (kl & (uint32_t)0x00000004) << 19;
sk0 |= (kl & (uint32_t)0x04000000) >> 10;
sk0 |= (kl & (uint32_t)0x00000010) << 26;
sk0 |= (kl & (uint32_t)0x01000000) >> 2;
sk0 |= kr & (uint32_t)0x00000100;
sk0 |= (kr & (uint32_t)0x00000008) << 1;
sk0 |= (kr & (uint32_t)0x00000200) << 4;
sk0 |= rotl(kr & (uint32_t)0x08000021, 6);
sk0 |= (kr & (uint32_t)0x01000000) >> 24;
sk0 |= (kr & (uint32_t)0x00000002) << 11;
sk0 |= (kr & (uint32_t)0x00100000) >> 18;
sk0 |= (kr & (uint32_t)0x00400000) >> 17;
sk0 |= (kr & (uint32_t)0x00800000) >> 14;
sk0 |= (kr & (uint32_t)0x02020000) >> 10;
sk0 |= (kr & (uint32_t)0x00080000) >> 5;
sk0 |= (kr & (uint32_t)0x00000040) >> 3;
sk0 |= (kr & (uint32_t)0x00000800) >> 1;
sk1 = kl & (uint32_t)0x02000000;
sk1 |= (kl & (uint32_t)0x00001000) << 5;
sk1 |= (kl & (uint32_t)0x00000200) << 11;
sk1 |= (kl & (uint32_t)0x00004000) << 15;
sk1 |= (kl & (uint32_t)0x00000020) << 16;
sk1 |= (kl & (uint32_t)0x00000800) << 17;
sk1 |= (kl & (uint32_t)0x00000001) << 24;
sk1 |= (kl & (uint32_t)0x00200000) >> 5;
sk1 |= (kr & (uint32_t)0x00000010) << 8;
sk1 |= (kr & (uint32_t)0x04000000) >> 17;
sk1 |= (kr & (uint32_t)0x00004000) >> 14;
sk1 |= (kr & (uint32_t)0x00000400) >> 9;
sk1 |= (kr & (uint32_t)0x00010000) >> 8;
sk1 |= (kr & (uint32_t)0x00001000) >> 7;
sk1 |= (kr & (uint32_t)0x00000080) >> 3;
sk1 |= (kr & (uint32_t)0x00008000) >> 2;
#endif
}
/* see inner.h */
unsigned
br_des_ct_keysched(uint32_t *skey, const void *key, size_t key_len)
{
switch (key_len) {
case 8:
keysched_unit(skey, key);
return 1;
case 16:
keysched_unit(skey, key);
keysched_unit(skey + 32, (const unsigned char *)key + 8);
br_des_rev_skey(skey + 32);
memcpy(skey + 64, skey, 32 * sizeof *skey);
return 3;
default:
keysched_unit(skey, key);
keysched_unit(skey + 32, (const unsigned char *)key + 8);
br_des_rev_skey(skey + 32);
keysched_unit(skey + 64, (const unsigned char *)key + 16);
return 3;
}
}
/*
* DES confusion function. This function performs expansion E (32 to
* 48 bits), XOR with subkey, S-boxes, and permutation P.
*/
static inline uint32_t
Fconf(uint32_t r0, const uint32_t *sk)
{
/*
* Each 6->4 S-box is virtually turned into four 6->1 boxes; we
* thus end up with 32 boxes that we call "T-boxes" here. We will
* evaluate them with bitslice code.
*
* Each T-box is a circuit of multiplexers (sort of) and thus
* takes 70 inputs: the 6 actual T-box inputs, and 64 constants
* that describe the T-box output for all combinations of the
* 6 inputs. With this model, all T-boxes are identical (with
* distinct inputs) and thus can be executed in parallel with
* bitslice code.
*
* T-boxes are numbered from 0 to 31, in least-to-most
* significant order. Thus, S-box S1 corresponds to T-boxes 31,
* 30, 29 and 28, in that order. T-box 'n' is computed with the
* bits at rank 'n' in the 32-bit words.
*
* Words x0 to x5 contain the T-box inputs 0 to 5.
*/
uint32_t x0, x1, x2, x3, x4, x5, z0;
uint32_t y0, y1, y2, y3, y4, y5, y6, y7, y8, y9;
uint32_t y10, y11, y12, y13, y14, y15, y16, y17, y18, y19;
uint32_t y20, y21, y22, y23, y24, y25, y26, y27, y28, y29;
uint32_t y30;
/*
* Spread input bits over the 6 input words x*.
*/
x1 = r0 & (uint32_t)0x11111111;
x2 = (r0 >> 1) & (uint32_t)0x11111111;
x3 = (r0 >> 2) & (uint32_t)0x11111111;
x4 = (r0 >> 3) & (uint32_t)0x11111111;
x1 = (x1 << 4) - x1;
x2 = (x2 << 4) - x2;
x3 = (x3 << 4) - x3;
x4 = (x4 << 4) - x4;
x0 = (x4 << 4) | (x4 >> 28);
x5 = (x1 >> 4) | (x1 << 28);
/*
* XOR with the subkey for this round.
*/
x0 ^= sk[0];
x1 ^= sk[1];
x2 ^= sk[2];
x3 ^= sk[3];
x4 ^= sk[4];
x5 ^= sk[5];
/*
* The T-boxes are done in parallel, since they all use a
* "tree of multiplexer". We use "fake multiplexers":
*
* y = a ^ (x & b)
*
* computes y as either 'a' (if x == 0) or 'a ^ b' (if x == 1).
*/
y0 = (uint32_t)0xEFA72C4D ^ (x0 & (uint32_t)0xEC7AC69C);
y1 = (uint32_t)0xAEAAEDFF ^ (x0 & (uint32_t)0x500FB821);
y2 = (uint32_t)0x37396665 ^ (x0 & (uint32_t)0x40EFA809);
y3 = (uint32_t)0x68D7B833 ^ (x0 & (uint32_t)0xA5EC0B28);
y4 = (uint32_t)0xC9C755BB ^ (x0 & (uint32_t)0x252CF820);
y5 = (uint32_t)0x73FC3606 ^ (x0 & (uint32_t)0x40205801);
y6 = (uint32_t)0xA2A0A918 ^ (x0 & (uint32_t)0xE220F929);
y7 = (uint32_t)0x8222BD90 ^ (x0 & (uint32_t)0x44A3F9E1);
y8 = (uint32_t)0xD6B6AC77 ^ (x0 & (uint32_t)0x794F104A);
y9 = (uint32_t)0x3069300C ^ (x0 & (uint32_t)0x026F320B);
y10 = (uint32_t)0x6CE0D5CC ^ (x0 & (uint32_t)0x7640B01A);
y11 = (uint32_t)0x59A9A22D ^ (x0 & (uint32_t)0x238F1572);
y12 = (uint32_t)0xAC6D0BD4 ^ (x0 & (uint32_t)0x7A63C083);
y13 = (uint32_t)0x21C83200 ^ (x0 & (uint32_t)0x11CCA000);
y14 = (uint32_t)0xA0E62188 ^ (x0 & (uint32_t)0x202F69AA);
/* y15 = (uint32_t)0x00000000 ^ (x0 & (uint32_t)0x00000000); */
y16 = (uint32_t)0xAF7D655A ^ (x0 & (uint32_t)0x51B33BE9);
y17 = (uint32_t)0xF0168AA3 ^ (x0 & (uint32_t)0x3B0FE8AE);
y18 = (uint32_t)0x90AA30C6 ^ (x0 & (uint32_t)0x90BF8816);
y19 = (uint32_t)0x5AB2750A ^ (x0 & (uint32_t)0x09E34F9B);
y20 = (uint32_t)0x5391BE65 ^ (x0 & (uint32_t)0x0103BE88);
y21 = (uint32_t)0x93372BAF ^ (x0 & (uint32_t)0x49AC8E25);
y22 = (uint32_t)0xF288210C ^ (x0 & (uint32_t)0x922C313D);
y23 = (uint32_t)0x920AF5C0 ^ (x0 & (uint32_t)0x70EF31B0);
y24 = (uint32_t)0x63D312C0 ^ (x0 & (uint32_t)0x6A707100);
y25 = (uint32_t)0x537B3006 ^ (x0 & (uint32_t)0xB97C9011);
y26 = (uint32_t)0xA2EFB0A5 ^ (x0 & (uint32_t)0xA320C959);
y27 = (uint32_t)0xBC8F96A5 ^ (x0 & (uint32_t)0x6EA0AB4A);
y28 = (uint32_t)0xFAD176A5 ^ (x0 & (uint32_t)0x6953DDF8);
y29 = (uint32_t)0x665A14A3 ^ (x0 & (uint32_t)0xF74F3E2B);
y30 = (uint32_t)0xF2EFF0CC ^ (x0 & (uint32_t)0xF0306CAD);
/* y31 = (uint32_t)0x00000000 ^ (x0 & (uint32_t)0x00000000); */
y0 = y0 ^ (x1 & y1);
y1 = y2 ^ (x1 & y3);
y2 = y4 ^ (x1 & y5);
y3 = y6 ^ (x1 & y7);
y4 = y8 ^ (x1 & y9);
y5 = y10 ^ (x1 & y11);
y6 = y12 ^ (x1 & y13);
y7 = y14; /* was: y14 ^ (x1 & y15) */
y8 = y16 ^ (x1 & y17);
y9 = y18 ^ (x1 & y19);
y10 = y20 ^ (x1 & y21);
y11 = y22 ^ (x1 & y23);
y12 = y24 ^ (x1 & y25);
y13 = y26 ^ (x1 & y27);
y14 = y28 ^ (x1 & y29);
y15 = y30; /* was: y30 ^ (x1 & y31) */
y0 = y0 ^ (x2 & y1);
y1 = y2 ^ (x2 & y3);
y2 = y4 ^ (x2 & y5);
y3 = y6 ^ (x2 & y7);
y4 = y8 ^ (x2 & y9);
y5 = y10 ^ (x2 & y11);
y6 = y12 ^ (x2 & y13);
y7 = y14 ^ (x2 & y15);
y0 = y0 ^ (x3 & y1);
y1 = y2 ^ (x3 & y3);
y2 = y4 ^ (x3 & y5);
y3 = y6 ^ (x3 & y7);
y0 = y0 ^ (x4 & y1);
y1 = y2 ^ (x4 & y3);
y0 = y0 ^ (x5 & y1);
/*
* The P permutation:
* -- Each bit move is converted into a mask + left rotation.
* -- Rotations that use the same movement are coalesced together.
* -- Left and right shifts are used as alternatives to a rotation
* where appropriate (this will help architectures that do not have
* a rotation opcode).
*/
z0 = (y0 & (uint32_t)0x00000004) << 3;
z0 |= (y0 & (uint32_t)0x00004000) << 4;
z0 |= rotl(y0 & 0x12020120, 5);
z0 |= (y0 & (uint32_t)0x00100000) << 6;
z0 |= (y0 & (uint32_t)0x00008000) << 9;
z0 |= (y0 & (uint32_t)0x04000000) >> 22;
z0 |= (y0 & (uint32_t)0x00000001) << 11;
z0 |= rotl(y0 & 0x20000200, 12);
z0 |= (y0 & (uint32_t)0x00200000) >> 19;
z0 |= (y0 & (uint32_t)0x00000040) << 14;
z0 |= (y0 & (uint32_t)0x00010000) << 15;
z0 |= (y0 & (uint32_t)0x00000002) << 16;
z0 |= rotl(y0 & 0x40801800, 17);
z0 |= (y0 & (uint32_t)0x00080000) >> 13;
z0 |= (y0 & (uint32_t)0x00000010) << 21;
z0 |= (y0 & (uint32_t)0x01000000) >> 10;
z0 |= rotl(y0 & 0x88000008, 24);
z0 |= (y0 & (uint32_t)0x00000480) >> 7;
z0 |= (y0 & (uint32_t)0x00442000) >> 6;
return z0;
}
/*
* Process one block through 16 successive rounds, omitting the swap
* in the final round.
*/
static void
process_block_unit(uint32_t *pl, uint32_t *pr, const uint32_t *sk_exp)
{
int i;
uint32_t l, r;
l = *pl;
r = *pr;
for (i = 0; i < 16; i ++) {
uint32_t t;
t = l ^ Fconf(r, sk_exp);
l = r;
r = t;
sk_exp += 6;
}
*pl = r;
*pr = l;
}
/* see inner.h */
void
br_des_ct_process_block(unsigned num_rounds,
const uint32_t *sk_exp, void *block)
{
unsigned char *buf;
uint32_t l, r;
buf = block;
l = br_dec32be(buf);
r = br_dec32be(buf + 4);
br_des_do_IP(&l, &r);
while (num_rounds -- > 0) {
process_block_unit(&l, &r, sk_exp);
sk_exp += 96;
}
br_des_do_invIP(&l, &r);
br_enc32be(buf, l);
br_enc32be(buf + 4, r);
}
/* see inner.h */
void
br_des_ct_skey_expand(uint32_t *sk_exp,
unsigned num_rounds, const uint32_t *skey)
{
num_rounds <<= 4;
while (num_rounds -- > 0) {
uint32_t v, w0, w1, w2, w3;
v = *skey ++;
w0 = v & 0x11111111;
w1 = (v >> 1) & 0x11111111;
w2 = (v >> 2) & 0x11111111;
w3 = (v >> 3) & 0x11111111;
*sk_exp ++ = (w0 << 4) - w0;
*sk_exp ++ = (w1 << 4) - w1;
*sk_exp ++ = (w2 << 4) - w2;
*sk_exp ++ = (w3 << 4) - w3;
v = *skey ++;
w0 = v & 0x11111111;
w1 = (v >> 1) & 0x11111111;
*sk_exp ++ = (w0 << 4) - w0;
*sk_exp ++ = (w1 << 4) - w1;
}
}