| // SPDX-License-Identifier: BSD-2-Clause |
| /* LibTomCrypt, modular cryptographic library -- Tom St Denis |
| * |
| * LibTomCrypt is a library that provides various cryptographic |
| * algorithms in a highly modular and flexible manner. |
| * |
| * The library is free for all purposes without any express |
| * guarantee it works. |
| */ |
| |
| /** |
| @file gcm_mult_h.c |
| GCM implementation, do the GF mult, by Tom St Denis |
| */ |
| #include "tomcrypt_private.h" |
| |
| #if defined(LTC_GCM_MODE) |
| /** |
| GCM multiply by H |
| @param gcm The GCM state which holds the H value |
| @param I The value to multiply H by |
| */ |
| void gcm_mult_h(const gcm_state *gcm, unsigned char *I) |
| { |
| unsigned char T[16]; |
| #ifdef LTC_GCM_TABLES |
| int x; |
| #ifdef LTC_GCM_TABLES_SSE2 |
| asm("movdqa (%0),%%xmm0"::"r"(&gcm->PC[0][I[0]][0])); |
| for (x = 1; x < 16; x++) { |
| asm("pxor (%0),%%xmm0"::"r"(&gcm->PC[x][I[x]][0])); |
| } |
| asm("movdqa %%xmm0,(%0)"::"r"(&T)); |
| #else |
| int y; |
| XMEMCPY(T, &gcm->PC[0][I[0]][0], 16); |
| for (x = 1; x < 16; x++) { |
| #ifdef LTC_FAST |
| for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) { |
| *(LTC_FAST_TYPE_PTR_CAST(T + y)) ^= *(LTC_FAST_TYPE_PTR_CAST(&gcm->PC[x][I[x]][y])); |
| } |
| #else |
| for (y = 0; y < 16; y++) { |
| T[y] ^= gcm->PC[x][I[x]][y]; |
| } |
| #endif /* LTC_FAST */ |
| } |
| #endif /* LTC_GCM_TABLES_SSE2 */ |
| #else |
| gcm_gf_mult(gcm->H, I, T); |
| #endif |
| XMEMCPY(I, T, 16); |
| } |
| #endif |
| |
| /* ref: $Format:%D$ */ |
| /* git commit: $Format:%H$ */ |
| /* commit time: $Format:%ai$ */ |