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