cosmopolitan/libc/crypto/rijndael.c

74 lines
3.4 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ This program is free software; you can redistribute it and/or modify │
│ it under the terms of the GNU General Public License as published by │
│ the Free Software Foundation; version 2 of the License. │
│ │
│ This program is distributed in the hope that it will be useful, but │
│ WITHOUT ANY WARRANTY; without even the implied warranty of │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
│ General Public License for more details. │
│ │
│ You should have received a copy of the GNU General Public License │
│ along with this program; if not, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/emmintrin.internal.h"
#include "libc/crypto/rijndael.h"
#include "libc/nexgen32e/x86feature.h"
forceinline aes_block_t rijndael$westmere(uint32_t n, aes_block_t x,
const struct Rijndael *ctx) {
uint32_t i;
x ^= ctx->rk[0].xmm;
for (i = 1; i < n; ++i) {
asm("aesenc\t%2,%0" : "=x"(x) : "0"(x), "m"(ctx->rk[i].xmm));
}
asm("aesenclast\t%2,%0" : "=x"(x) : "0"(x), "m"(ctx->rk[i].xmm));
return x;
}
static noinline aes_block_t rijndael$pure(uint32_t n, aes_block_t x,
const struct Rijndael *ctx) {
uint32_t i, j;
__v16qu b1, b2;
aes_block_t u1, u2, u3, u4;
x ^= ctx->rk[0].xmm;
for (i = 1; i < n + 1; ++i) {
b2 = b1 = (__v16qu)x;
for (j = 0; j < 16; ++j) {
b2[j % 4 + 13 * j / 4 % 4 * 4] = kAesSbox[b1[j]];
}
u1 = (aes_block_t)b2;
if (i != n) {
u2 = u1 >> 010 | u1 << 030;
u3 = u1 ^ u2;
u4 = u3 & 0x80808080;
u3 = ((u3 ^ u4) << 1) ^ ((u4 >> 7) * 0x1b);
u1 = u3 ^ u2 ^ (u1 >> 020 | u1 << 020) ^ (u1 >> 030 | u1 << 010);
}
x = ctx->rk[i].xmm ^ u1;
}
return x;
}
/**
* Encrypts paragraph w/ AES.
*
* @param n is 14 for AES-256, 12 for AES-192, and 10 for AES-128
* @param x is 128-bit chunk of plaintext to encrypt
* @param ctx was initialized by rijndaelinit()
* @return result of transformation
*/
aes_block_t rijndael(uint32_t n, aes_block_t x, const struct Rijndael *ctx) {
if (X86_HAVE(AES)) {
return rijndael$westmere(n, x, ctx);
} else {
return rijndael$pure(n, x, ctx);
}
}