/*      $NetBSD: aes_ct64.c,v 1.1 2025/11/23 22:44:13 riastradh Exp $   */

/*
 * 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 <sys/cdefs.h>
__KERNEL_RCSID(1, "$NetBSD: aes_ct64.c,v 1.1 2025/11/23 22:44:13 riastradh Exp $");

#include <sys/types.h>

#ifdef _KERNEL
#include <lib/libkern/libkern.h>
#else
#include <string.h>
#endif

#include <crypto/aes/aes_bear64.h>

static void
br_range_dec32le(uint32_t *p32, size_t nwords, const void *v)
{
        const uint8_t *p8 = v;

        while (nwords --> 0) {
                uint32_t x0 = *p8++;
                uint32_t x1 = *p8++;
                uint32_t x2 = *p8++;
                uint32_t x3 = *p8++;

                *p32++ = x0 | (x1 << 8) | (x2 << 16) | (x3 << 24);
        }
}

/* see inner.h */
void
br_aes_ct64_bitslice_Sbox(uint64_t q[static 8])
{
        /*
         * 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).
         */

        uint64_t x0, x1, x2, x3, x4, x5, x6, x7;
        uint64_t y1, y2, y3, y4, y5, y6, y7, y8, y9;
        uint64_t y10, y11, y12, y13, y14, y15, y16, y17, y18, y19;
        uint64_t y20, y21;
        uint64_t z0, z1, z2, z3, z4, z5, z6, z7, z8, z9;
        uint64_t z10, z11, z12, z13, z14, z15, z16, z17;
        uint64_t t0, t1, t2, t3, t4, t5, t6, t7, t8, t9;
        uint64_t t10, t11, t12, t13, t14, t15, t16, t17, t18, t19;
        uint64_t t20, t21, t22, t23, t24, t25, t26, t27, t28, t29;
        uint64_t t30, t31, t32, t33, t34, t35, t36, t37, t38, t39;
        uint64_t t40, t41, t42, t43, t44, t45, t46, t47, t48, t49;
        uint64_t t50, t51, t52, t53, t54, t55, t56, t57, t58, t59;
        uint64_t t60, t61, t62, t63, t64, t65, t66, t67;
        uint64_t s0, s1, s2, s3, s4, s5, s6, 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;
}

/* see inner.h */
void
br_aes_ct64_ortho(uint64_t q[static 8])
{
#define SWAPN(cl, ch, s, x, y)   do { \
                uint64_t a, b; \
                a = (x); \
                b = (y); \
                (x) = (a & (uint64_t)cl) | ((b & (uint64_t)cl) << (s)); \
                (y) = ((a & (uint64_t)ch) >> (s)) | (b & (uint64_t)ch); \
        } while (0)

#define SWAP2(x, y)    SWAPN(0x5555555555555555, 0xAAAAAAAAAAAAAAAA,  1, x, y)
#define SWAP4(x, y)    SWAPN(0x3333333333333333, 0xCCCCCCCCCCCCCCCC,  2, x, y)
#define SWAP8(x, y)    SWAPN(0x0F0F0F0F0F0F0F0F, 0xF0F0F0F0F0F0F0F0,  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]);
}

/* see inner.h */
void
br_aes_ct64_interleave_in(uint64_t q0[static 1], uint64_t q1[static 1],
        const uint32_t w[static 4])
{
        uint64_t x0, x1, x2, x3;

        x0 = w[0];
        x1 = w[1];
        x2 = w[2];
        x3 = w[3];
        x0 |= (x0 << 16);
        x1 |= (x1 << 16);
        x2 |= (x2 << 16);
        x3 |= (x3 << 16);
        x0 &= (uint64_t)0x0000FFFF0000FFFF;
        x1 &= (uint64_t)0x0000FFFF0000FFFF;
        x2 &= (uint64_t)0x0000FFFF0000FFFF;
        x3 &= (uint64_t)0x0000FFFF0000FFFF;
        x0 |= (x0 << 8);
        x1 |= (x1 << 8);
        x2 |= (x2 << 8);
        x3 |= (x3 << 8);
        x0 &= (uint64_t)0x00FF00FF00FF00FF;
        x1 &= (uint64_t)0x00FF00FF00FF00FF;
        x2 &= (uint64_t)0x00FF00FF00FF00FF;
        x3 &= (uint64_t)0x00FF00FF00FF00FF;
        *q0 = x0 | (x2 << 8);
        *q1 = x1 | (x3 << 8);
}

/* see inner.h */
void
br_aes_ct64_interleave_out(uint32_t w[static 4], uint64_t q0, uint64_t q1)
{
        uint64_t x0, x1, x2, x3;

        x0 = q0 & (uint64_t)0x00FF00FF00FF00FF;
        x1 = q1 & (uint64_t)0x00FF00FF00FF00FF;
        x2 = (q0 >> 8) & (uint64_t)0x00FF00FF00FF00FF;
        x3 = (q1 >> 8) & (uint64_t)0x00FF00FF00FF00FF;
        x0 |= (x0 >> 8);
        x1 |= (x1 >> 8);
        x2 |= (x2 >> 8);
        x3 |= (x3 >> 8);
        x0 &= (uint64_t)0x0000FFFF0000FFFF;
        x1 &= (uint64_t)0x0000FFFF0000FFFF;
        x2 &= (uint64_t)0x0000FFFF0000FFFF;
        x3 &= (uint64_t)0x0000FFFF0000FFFF;
        w[0] = (uint32_t)x0 | (uint32_t)(x0 >> 16);
        w[1] = (uint32_t)x1 | (uint32_t)(x1 >> 16);
        w[2] = (uint32_t)x2 | (uint32_t)(x2 >> 16);
        w[3] = (uint32_t)x3 | (uint32_t)(x3 >> 16);
}

static const unsigned char Rcon[] = {
        0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36
};

static uint32_t
sub_word(uint32_t x)
{
        uint64_t q[8];

        memset(q, 0, sizeof q);
        q[0] = x;
        br_aes_ct64_ortho(q);
        br_aes_ct64_bitslice_Sbox(q);
        br_aes_ct64_ortho(q);
        return (uint32_t)q[0];
}

/* see inner.h */
unsigned
br_aes_ct64_keysched(uint64_t comp_skey[static 30],
        const void *key, size_t key_len)
{
        unsigned num_rounds;
        int i, j, k, nk, nkf;
        uint32_t tmp;
        uint32_t skey[60];

        switch (key_len) {
        case 16:
                num_rounds = 10;
                break;
        case 24:
                num_rounds = 12;
                break;
        case 32:
                num_rounds = 14;
                break;
        default:
                /* abort(); */
                return 0;
        }
        nk = (int)(key_len >> 2);
        nkf = (int)((num_rounds + 1) << 2);
        br_range_dec32le(skey, (key_len >> 2), key);
        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 ++;
                }
        }

        for (i = 0, j = 0; i < nkf; i += 4, j += 2) {
                uint64_t q[8];

                br_aes_ct64_interleave_in(&q[0], &q[4], skey + i);
                q[1] = q[0];
                q[2] = q[0];
                q[3] = q[0];
                q[5] = q[4];
                q[6] = q[4];
                q[7] = q[4];
                br_aes_ct64_ortho(q);
                comp_skey[j + 0] =
                          (q[0] & (uint64_t)0x1111111111111111)
                        | (q[1] & (uint64_t)0x2222222222222222)
                        | (q[2] & (uint64_t)0x4444444444444444)
                        | (q[3] & (uint64_t)0x8888888888888888);
                comp_skey[j + 1] =
                          (q[4] & (uint64_t)0x1111111111111111)
                        | (q[5] & (uint64_t)0x2222222222222222)
                        | (q[6] & (uint64_t)0x4444444444444444)
                        | (q[7] & (uint64_t)0x8888888888888888);
        }
        return num_rounds;
}

/* see inner.h */
void
br_aes_ct64_skey_expand(uint64_t skey[static 120],
        unsigned num_rounds, const uint64_t comp_skey[static 30])
{
        unsigned u, v, n;

        n = (num_rounds + 1) << 1;
        for (u = 0, v = 0; u < n; u ++, v += 4) {
                uint64_t x0, x1, x2, x3;

                x0 = x1 = x2 = x3 = comp_skey[u];
                x0 &= (uint64_t)0x1111111111111111;
                x1 &= (uint64_t)0x2222222222222222;
                x2 &= (uint64_t)0x4444444444444444;
                x3 &= (uint64_t)0x8888888888888888;
                x1 >>= 1;
                x2 >>= 2;
                x3 >>= 3;
                skey[v + 0] = (x0 << 4) - x0;
                skey[v + 1] = (x1 << 4) - x1;
                skey[v + 2] = (x2 << 4) - x2;
                skey[v + 3] = (x3 << 4) - x3;
        }
}

/* NetBSD additions, for computing the standard AES key schedule */

unsigned
br_aes_ct64_keysched_stdenc(uint32_t *skey, const void *key, size_t key_len)
{
        unsigned num_rounds;
        int i, j, k, nk, 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:
                /* abort(); */
                return 0;
        }
        nk = (int)(key_len >> 2);
        nkf = (int)((num_rounds + 1) << 2);
        tmp = 0;
        for (i = 0; i < nk; i ++) {
                tmp = br_dec32le((const unsigned char *)key + (i << 2));
                skey[i] = tmp;
        }
        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;
}

unsigned
br_aes_ct64_keysched_stddec(uint32_t *skey, const void *key, size_t key_len)
{
        uint32_t tkey[60];
        uint64_t q[8];
        unsigned num_rounds;
        unsigned i;

        num_rounds = br_aes_ct64_keysched_stdenc(skey, key, key_len);
        if (num_rounds == 0)
                return 0;

        q[1] = q[2] = q[3] = 0;
        q[5] = q[6] = q[7] = 0;

        tkey[0] = skey[4*num_rounds + 0];
        tkey[1] = skey[4*num_rounds + 1];
        tkey[2] = skey[4*num_rounds + 2];
        tkey[3] = skey[4*num_rounds + 3];
        for (i = 1; i < num_rounds; i++) {
                br_aes_ct64_interleave_in(&q[0], &q[4], skey + 4*i);
                br_aes_ct64_ortho(q);
                br_aes_ct64_inv_mix_columns(q);
                br_aes_ct64_ortho(q);
                br_aes_ct64_interleave_out(&tkey[4*(num_rounds - i)],
                    q[0], q[4]);
        }
        tkey[4*num_rounds + 0] = skey[0];
        tkey[4*num_rounds + 1] = skey[1];
        tkey[4*num_rounds + 2] = skey[2];
        tkey[4*num_rounds + 3] = skey[3];

        memcpy(skey, tkey, 4*(num_rounds + 1)*sizeof(uint32_t));
        explicit_memset(tkey, 0, 4*(num_rounds + 1)*sizeof(uint32_t));
        return num_rounds;
}