/* * Copyright (C) 2015 Martin Willi * Copyright (C) 2015 revosec AG * * 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; either version 2 of the License, or (at your * option) any later version. See . * * 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. */ #include "aesni_cbc.h" #include "aesni_key.h" /** * Pipeline parallelism we use for CBC decryption */ #define CBC_DECRYPT_PARALLELISM 4 typedef struct private_aesni_cbc_t private_aesni_cbc_t; /** * CBC en/decryption method type */ typedef void (*aesni_cbc_fn_t)(aesni_key_t*, u_int, u_char*, u_char*, u_char*); /** * Private data of an aesni_cbc_t object. */ struct private_aesni_cbc_t { /** * Public aesni_cbc_t interface. */ aesni_cbc_t public; /** * Key size */ u_int key_size; /** * Encryption key schedule */ aesni_key_t *ekey; /** * Decryption key schedule */ aesni_key_t *dkey; /** * Encryption method */ aesni_cbc_fn_t encrypt; /** * Decryption method */ aesni_cbc_fn_t decrypt; }; /** * AES-128 CBC encryption */ static void encrypt_cbc128(aesni_key_t *key, u_int blocks, u_char *in, u_char *iv, u_char *out) { __m128i k0, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10; __m128i t, fb, *bi, *bo; int i; k0 = key->schedule[0]; k1 = key->schedule[1]; k2 = key->schedule[2]; k3 = key->schedule[3]; k4 = key->schedule[4]; k5 = key->schedule[5]; k6 = key->schedule[6]; k7 = key->schedule[7]; k8 = key->schedule[8]; k9 = key->schedule[9]; k10 = key->schedule[10]; bi = (__m128i*)in; bo = (__m128i*)out; fb = _mm_loadu_si128((__m128i*)iv); for (i = 0; i < blocks; i++) { t = _mm_loadu_si128(bi + i); fb = _mm_xor_si128(t, fb); fb = _mm_xor_si128(fb, k0); fb = _mm_aesenc_si128(fb, k1); fb = _mm_aesenc_si128(fb, k2); fb = _mm_aesenc_si128(fb, k3); fb = _mm_aesenc_si128(fb, k4); fb = _mm_aesenc_si128(fb, k5); fb = _mm_aesenc_si128(fb, k6); fb = _mm_aesenc_si128(fb, k7); fb = _mm_aesenc_si128(fb, k8); fb = _mm_aesenc_si128(fb, k9); fb = _mm_aesenclast_si128(fb, k10); _mm_storeu_si128(bo + i, fb); } } /** * AES-128 CBC decryption */ static void decrypt_cbc128(aesni_key_t *key, u_int blocks, u_char *in, u_char *iv, u_char *out) { __m128i k0, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10; __m128i last, *bi, *bo; __m128i t1, t2, t3, t4; __m128i f1, f2, f3, f4; u_int i, pblocks; k0 = key->schedule[0]; k1 = key->schedule[1]; k2 = key->schedule[2]; k3 = key->schedule[3]; k4 = key->schedule[4]; k5 = key->schedule[5]; k6 = key->schedule[6]; k7 = key->schedule[7]; k8 = key->schedule[8]; k9 = key->schedule[9]; k10 = key->schedule[10]; bi = (__m128i*)in; bo = (__m128i*)out; pblocks = blocks - (blocks % CBC_DECRYPT_PARALLELISM); f1 = _mm_loadu_si128((__m128i*)iv); for (i = 0; i < pblocks; i += CBC_DECRYPT_PARALLELISM) { t1 = _mm_loadu_si128(bi + i + 0); t2 = _mm_loadu_si128(bi + i + 1); t3 = _mm_loadu_si128(bi + i + 2); t4 = _mm_loadu_si128(bi + i + 3); f2 = t1; f3 = t2; f4 = t3; last = t4; t1 = _mm_xor_si128(t1, k0); t2 = _mm_xor_si128(t2, k0); t3 = _mm_xor_si128(t3, k0); t4 = _mm_xor_si128(t4, k0); t1 = _mm_aesdec_si128(t1, k1); t2 = _mm_aesdec_si128(t2, k1); t3 = _mm_aesdec_si128(t3, k1); t4 = _mm_aesdec_si128(t4, k1); t1 = _mm_aesdec_si128(t1, k2); t2 = _mm_aesdec_si128(t2, k2); t3 = _mm_aesdec_si128(t3, k2); t4 = _mm_aesdec_si128(t4, k2); t1 = _mm_aesdec_si128(t1, k3); t2 = _mm_aesdec_si128(t2, k3); t3 = _mm_aesdec_si128(t3, k3); t4 = _mm_aesdec_si128(t4, k3); t1 = _mm_aesdec_si128(t1, k4); t2 = _mm_aesdec_si128(t2, k4); t3 = _mm_aesdec_si128(t3, k4); t4 = _mm_aesdec_si128(t4, k4); t1 = _mm_aesdec_si128(t1, k5); t2 = _mm_aesdec_si128(t2, k5); t3 = _mm_aesdec_si128(t3, k5); t4 = _mm_aesdec_si128(t4, k5); t1 = _mm_aesdec_si128(t1, k6); t2 = _mm_aesdec_si128(t2, k6); t3 = _mm_aesdec_si128(t3, k6); t4 = _mm_aesdec_si128(t4, k6); t1 = _mm_aesdec_si128(t1, k7); t2 = _mm_aesdec_si128(t2, k7); t3 = _mm_aesdec_si128(t3, k7); t4 = _mm_aesdec_si128(t4, k7); t1 = _mm_aesdec_si128(t1, k8); t2 = _mm_aesdec_si128(t2, k8); t3 = _mm_aesdec_si128(t3, k8); t4 = _mm_aesdec_si128(t4, k8); t1 = _mm_aesdec_si128(t1, k9); t2 = _mm_aesdec_si128(t2, k9); t3 = _mm_aesdec_si128(t3, k9); t4 = _mm_aesdec_si128(t4, k9); t1 = _mm_aesdeclast_si128(t1, k10); t2 = _mm_aesdeclast_si128(t2, k10); t3 = _mm_aesdeclast_si128(t3, k10); t4 = _mm_aesdeclast_si128(t4, k10); t1 = _mm_xor_si128(t1, f1); t2 = _mm_xor_si128(t2, f2); t3 = _mm_xor_si128(t3, f3); t4 = _mm_xor_si128(t4, f4); _mm_storeu_si128(bo + i + 0, t1); _mm_storeu_si128(bo + i + 1, t2); _mm_storeu_si128(bo + i + 2, t3); _mm_storeu_si128(bo + i + 3, t4); f1 = last; } for (i = pblocks; i < blocks; i++) { last = _mm_loadu_si128(bi + i); t1 = _mm_xor_si128(last, k0); t1 = _mm_aesdec_si128(t1, k1); t1 = _mm_aesdec_si128(t1, k2); t1 = _mm_aesdec_si128(t1, k3); t1 = _mm_aesdec_si128(t1, k4); t1 = _mm_aesdec_si128(t1, k5); t1 = _mm_aesdec_si128(t1, k6); t1 = _mm_aesdec_si128(t1, k7); t1 = _mm_aesdec_si128(t1, k8); t1 = _mm_aesdec_si128(t1, k9); t1 = _mm_aesdeclast_si128(t1, k10); t1 = _mm_xor_si128(t1, f1); _mm_storeu_si128(bo + i, t1); f1 = last; } } /** * AES-192 CBC encryption */ static void encrypt_cbc192(aesni_key_t *key, u_int blocks, u_char *in, u_char *iv, u_char *out) { __m128i k0, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12; __m128i t, fb, *bi, *bo; int i; k0 = key->schedule[0]; k1 = key->schedule[1]; k2 = key->schedule[2]; k3 = key->schedule[3]; k4 = key->schedule[4]; k5 = key->schedule[5]; k6 = key->schedule[6]; k7 = key->schedule[7]; k8 = key->schedule[8]; k9 = key->schedule[9]; k10 = key->schedule[10]; k11 = key->schedule[11]; k12 = key->schedule[12]; bi = (__m128i*)in; bo = (__m128i*)out; fb = _mm_loadu_si128((__m128i*)iv); for (i = 0; i < blocks; i++) { t = _mm_loadu_si128(bi + i); fb = _mm_xor_si128(t, fb); fb = _mm_xor_si128(fb, k0); fb = _mm_aesenc_si128(fb, k1); fb = _mm_aesenc_si128(fb, k2); fb = _mm_aesenc_si128(fb, k3); fb = _mm_aesenc_si128(fb, k4); fb = _mm_aesenc_si128(fb, k5); fb = _mm_aesenc_si128(fb, k6); fb = _mm_aesenc_si128(fb, k7); fb = _mm_aesenc_si128(fb, k8); fb = _mm_aesenc_si128(fb, k9); fb = _mm_aesenc_si128(fb, k10); fb = _mm_aesenc_si128(fb, k11); fb = _mm_aesenclast_si128(fb, k12); _mm_storeu_si128(bo + i, fb); } } /** * AES-192 CBC decryption */ static void decrypt_cbc192(aesni_key_t *key, u_int blocks, u_char *in, u_char *iv, u_char *out) { __m128i k0, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12; __m128i last, *bi, *bo; __m128i t1, t2, t3, t4; __m128i f1, f2, f3, f4; u_int i, pblocks; k0 = key->schedule[0]; k1 = key->schedule[1]; k2 = key->schedule[2]; k3 = key->schedule[3]; k4 = key->schedule[4]; k5 = key->schedule[5]; k6 = key->schedule[6]; k7 = key->schedule[7]; k8 = key->schedule[8]; k9 = key->schedule[9]; k10 = key->schedule[10]; k11 = key->schedule[11]; k12 = key->schedule[12]; bi = (__m128i*)in; bo = (__m128i*)out; pblocks = blocks - (blocks % CBC_DECRYPT_PARALLELISM); f1 = _mm_loadu_si128((__m128i*)iv); for (i = 0; i < pblocks; i += CBC_DECRYPT_PARALLELISM) { t1 = _mm_loadu_si128(bi + i + 0); t2 = _mm_loadu_si128(bi + i + 1); t3 = _mm_loadu_si128(bi + i + 2); t4 = _mm_loadu_si128(bi + i + 3); f2 = t1; f3 = t2; f4 = t3; last = t4; t1 = _mm_xor_si128(t1, k0); t2 = _mm_xor_si128(t2, k0); t3 = _mm_xor_si128(t3, k0); t4 = _mm_xor_si128(t4, k0); t1 = _mm_aesdec_si128(t1, k1); t2 = _mm_aesdec_si128(t2, k1); t3 = _mm_aesdec_si128(t3, k1); t4 = _mm_aesdec_si128(t4, k1); t1 = _mm_aesdec_si128(t1, k2); t2 = _mm_aesdec_si128(t2, k2); t3 = _mm_aesdec_si128(t3, k2); t4 = _mm_aesdec_si128(t4, k2); t1 = _mm_aesdec_si128(t1, k3); t2 = _mm_aesdec_si128(t2, k3); t3 = _mm_aesdec_si128(t3, k3); t4 = _mm_aesdec_si128(t4, k3); t1 = _mm_aesdec_si128(t1, k4); t2 = _mm_aesdec_si128(t2, k4); t3 = _mm_aesdec_si128(t3, k4); t4 = _mm_aesdec_si128(t4, k4); t1 = _mm_aesdec_si128(t1, k5); t2 = _mm_aesdec_si128(t2, k5); t3 = _mm_aesdec_si128(t3, k5); t4 = _mm_aesdec_si128(t4, k5); t1 = _mm_aesdec_si128(t1, k6); t2 = _mm_aesdec_si128(t2, k6); t3 = _mm_aesdec_si128(t3, k6); t4 = _mm_aesdec_si128(t4, k6); t1 = _mm_aesdec_si128(t1, k7); t2 = _mm_aesdec_si128(t2, k7); t3 = _mm_aesdec_si128(t3, k7); t4 = _mm_aesdec_si128(t4, k7); t1 = _mm_aesdec_si128(t1, k8); t2 = _mm_aesdec_si128(t2, k8); t3 = _mm_aesdec_si128(t3, k8); t4 = _mm_aesdec_si128(t4, k8); t1 = _mm_aesdec_si128(t1, k9); t2 = _mm_aesdec_si128(t2, k9); t3 = _mm_aesdec_si128(t3, k9); t4 = _mm_aesdec_si128(t4, k9); t1 = _mm_aesdec_si128(t1, k10); t2 = _mm_aesdec_si128(t2, k10); t3 = _mm_aesdec_si128(t3, k10); t4 = _mm_aesdec_si128(t4, k10); t1 = _mm_aesdec_si128(t1, k11); t2 = _mm_aesdec_si128(t2, k11); t3 = _mm_aesdec_si128(t3, k11); t4 = _mm_aesdec_si128(t4, k11); t1 = _mm_aesdeclast_si128(t1, k12); t2 = _mm_aesdeclast_si128(t2, k12); t3 = _mm_aesdeclast_si128(t3, k12); t4 = _mm_aesdeclast_si128(t4, k12); t1 = _mm_xor_si128(t1, f1); t2 = _mm_xor_si128(t2, f2); t3 = _mm_xor_si128(t3, f3); t4 = _mm_xor_si128(t4, f4); _mm_storeu_si128(bo + i + 0, t1); _mm_storeu_si128(bo + i + 1, t2); _mm_storeu_si128(bo + i + 2, t3); _mm_storeu_si128(bo + i + 3, t4); f1 = last; } for (i = pblocks; i < blocks; i++) { last = _mm_loadu_si128(bi + i); t1 = _mm_xor_si128(last, k0); t1 = _mm_aesdec_si128(t1, k1); t1 = _mm_aesdec_si128(t1, k2); t1 = _mm_aesdec_si128(t1, k3); t1 = _mm_aesdec_si128(t1, k4); t1 = _mm_aesdec_si128(t1, k5); t1 = _mm_aesdec_si128(t1, k6); t1 = _mm_aesdec_si128(t1, k7); t1 = _mm_aesdec_si128(t1, k8); t1 = _mm_aesdec_si128(t1, k9); t1 = _mm_aesdec_si128(t1, k10); t1 = _mm_aesdec_si128(t1, k11); t1 = _mm_aesdeclast_si128(t1, k12); t1 = _mm_xor_si128(t1, f1); _mm_storeu_si128(bo + i, t1); f1 = last; } } /** * AES-256 CBC encryption */ static void encrypt_cbc256(aesni_key_t *key, u_int blocks, u_char *in, u_char *iv, u_char *out) { __m128i k0, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, k14; __m128i t, fb, *bi, *bo; int i; k0 = key->schedule[0]; k1 = key->schedule[1]; k2 = key->schedule[2]; k3 = key->schedule[3]; k4 = key->schedule[4]; k5 = key->schedule[5]; k6 = key->schedule[6]; k7 = key->schedule[7]; k8 = key->schedule[8]; k9 = key->schedule[9]; k10 = key->schedule[10]; k11 = key->schedule[11]; k12 = key->schedule[12]; k13 = key->schedule[13]; k14 = key->schedule[14]; bi = (__m128i*)in; bo = (__m128i*)out; fb = _mm_loadu_si128((__m128i*)iv); for (i = 0; i < blocks; i++) { t = _mm_loadu_si128(bi + i); fb = _mm_xor_si128(t, fb); fb = _mm_xor_si128(fb, k0); fb = _mm_aesenc_si128(fb, k1); fb = _mm_aesenc_si128(fb, k2); fb = _mm_aesenc_si128(fb, k3); fb = _mm_aesenc_si128(fb, k4); fb = _mm_aesenc_si128(fb, k5); fb = _mm_aesenc_si128(fb, k6); fb = _mm_aesenc_si128(fb, k7); fb = _mm_aesenc_si128(fb, k8); fb = _mm_aesenc_si128(fb, k9); fb = _mm_aesenc_si128(fb, k10); fb = _mm_aesenc_si128(fb, k11); fb = _mm_aesenc_si128(fb, k12); fb = _mm_aesenc_si128(fb, k13); fb = _mm_aesenclast_si128(fb, k14); _mm_storeu_si128(bo + i, fb); } } /** * AES-256 CBC decryption */ static void decrypt_cbc256(aesni_key_t *key, u_int blocks, u_char *in, u_char *iv, u_char *out) { __m128i k0, k1, k2, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, k14; __m128i last, *bi, *bo; __m128i t1, t2, t3, t4; __m128i f1, f2, f3, f4; u_int i, pblocks; k0 = key->schedule[0]; k1 = key->schedule[1]; k2 = key->schedule[2]; k3 = key->schedule[3]; k4 = key->schedule[4]; k5 = key->schedule[5]; k6 = key->schedule[6]; k7 = key->schedule[7]; k8 = key->schedule[8]; k9 = key->schedule[9]; k10 = key->schedule[10]; k11 = key->schedule[11]; k12 = key->schedule[12]; k13 = key->schedule[13]; k14 = key->schedule[14]; bi = (__m128i*)in; bo = (__m128i*)out; pblocks = blocks - (blocks % CBC_DECRYPT_PARALLELISM); f1 = _mm_loadu_si128((__m128i*)iv); for (i = 0; i < pblocks; i += CBC_DECRYPT_PARALLELISM) { t1 = _mm_loadu_si128(bi + i + 0); t2 = _mm_loadu_si128(bi + i + 1); t3 = _mm_loadu_si128(bi + i + 2); t4 = _mm_loadu_si128(bi + i + 3); f2 = t1; f3 = t2; f4 = t3; last = t4; t1 = _mm_xor_si128(t1, k0); t2 = _mm_xor_si128(t2, k0); t3 = _mm_xor_si128(t3, k0); t4 = _mm_xor_si128(t4, k0); t1 = _mm_aesdec_si128(t1, k1); t2 = _mm_aesdec_si128(t2, k1); t3 = _mm_aesdec_si128(t3, k1); t4 = _mm_aesdec_si128(t4, k1); t1 = _mm_aesdec_si128(t1, k2); t2 = _mm_aesdec_si128(t2, k2); t3 = _mm_aesdec_si128(t3, k2); t4 = _mm_aesdec_si128(t4, k2); t1 = _mm_aesdec_si128(t1, k3); t2 = _mm_aesdec_si128(t2, k3); t3 = _mm_aesdec_si128(t3, k3); t4 = _mm_aesdec_si128(t4, k3); t1 = _mm_aesdec_si128(t1, k4); t2 = _mm_aesdec_si128(t2, k4); t3 = _mm_aesdec_si128(t3, k4); t4 = _mm_aesdec_si128(t4, k4); t1 = _mm_aesdec_si128(t1, k5); t2 = _mm_aesdec_si128(t2, k5); t3 = _mm_aesdec_si128(t3, k5); t4 = _mm_aesdec_si128(t4, k5); t1 = _mm_aesdec_si128(t1, k6); t2 = _mm_aesdec_si128(t2, k6); t3 = _mm_aesdec_si128(t3, k6); t4 = _mm_aesdec_si128(t4, k6); t1 = _mm_aesdec_si128(t1, k7); t2 = _mm_aesdec_si128(t2, k7); t3 = _mm_aesdec_si128(t3, k7); t4 = _mm_aesdec_si128(t4, k7); t1 = _mm_aesdec_si128(t1, k8); t2 = _mm_aesdec_si128(t2, k8); t3 = _mm_aesdec_si128(t3, k8); t4 = _mm_aesdec_si128(t4, k8); t1 = _mm_aesdec_si128(t1, k9); t2 = _mm_aesdec_si128(t2, k9); t3 = _mm_aesdec_si128(t3, k9); t4 = _mm_aesdec_si128(t4, k9); t1 = _mm_aesdec_si128(t1, k10); t2 = _mm_aesdec_si128(t2, k10); t3 = _mm_aesdec_si128(t3, k10); t4 = _mm_aesdec_si128(t4, k10); t1 = _mm_aesdec_si128(t1, k11); t2 = _mm_aesdec_si128(t2, k11); t3 = _mm_aesdec_si128(t3, k11); t4 = _mm_aesdec_si128(t4, k11); t1 = _mm_aesdec_si128(t1, k12); t2 = _mm_aesdec_si128(t2, k12); t3 = _mm_aesdec_si128(t3, k12); t4 = _mm_aesdec_si128(t4, k12); t1 = _mm_aesdec_si128(t1, k13); t2 = _mm_aesdec_si128(t2, k13); t3 = _mm_aesdec_si128(t3, k13); t4 = _mm_aesdec_si128(t4, k13); t1 = _mm_aesdeclast_si128(t1, k14); t2 = _mm_aesdeclast_si128(t2, k14); t3 = _mm_aesdeclast_si128(t3, k14); t4 = _mm_aesdeclast_si128(t4, k14); t1 = _mm_xor_si128(t1, f1); t2 = _mm_xor_si128(t2, f2); t3 = _mm_xor_si128(t3, f3); t4 = _mm_xor_si128(t4, f4); _mm_storeu_si128(bo + i + 0, t1); _mm_storeu_si128(bo + i + 1, t2); _mm_storeu_si128(bo + i + 2, t3); _mm_storeu_si128(bo + i + 3, t4); f1 = last; } for (i = pblocks; i < blocks; i++) { last = _mm_loadu_si128(bi + i); t1 = _mm_xor_si128(last, k0); t1 = _mm_aesdec_si128(t1, k1); t1 = _mm_aesdec_si128(t1, k2); t1 = _mm_aesdec_si128(t1, k3); t1 = _mm_aesdec_si128(t1, k4); t1 = _mm_aesdec_si128(t1, k5); t1 = _mm_aesdec_si128(t1, k6); t1 = _mm_aesdec_si128(t1, k7); t1 = _mm_aesdec_si128(t1, k8); t1 = _mm_aesdec_si128(t1, k9); t1 = _mm_aesdec_si128(t1, k10); t1 = _mm_aesdec_si128(t1, k11); t1 = _mm_aesdec_si128(t1, k12); t1 = _mm_aesdec_si128(t1, k13); t1 = _mm_aesdeclast_si128(t1, k14); t1 = _mm_xor_si128(t1, f1); _mm_storeu_si128(bo + i, t1); f1 = last; } } /** * Do inline or allocated de/encryption using key schedule */ static bool crypt(aesni_cbc_fn_t fn, aesni_key_t *key, chunk_t data, chunk_t iv, chunk_t *out) { u_char *buf; if (!key || iv.len != AES_BLOCK_SIZE || data.len % AES_BLOCK_SIZE) { return FALSE; } if (out) { *out = chunk_alloc(data.len); buf = out->ptr; } else { buf = data.ptr; } fn(key, data.len / AES_BLOCK_SIZE, data.ptr, iv.ptr, buf); return TRUE; } METHOD(crypter_t, encrypt, bool, private_aesni_cbc_t *this, chunk_t data, chunk_t iv, chunk_t *encrypted) { return crypt(this->encrypt, this->ekey, data, iv, encrypted); } METHOD(crypter_t, decrypt, bool, private_aesni_cbc_t *this, chunk_t data, chunk_t iv, chunk_t *decrypted) { return crypt(this->decrypt, this->dkey, data, iv, decrypted); } METHOD(crypter_t, get_block_size, size_t, private_aesni_cbc_t *this) { return AES_BLOCK_SIZE; } METHOD(crypter_t, get_iv_size, size_t, private_aesni_cbc_t *this) { return AES_BLOCK_SIZE; } METHOD(crypter_t, get_key_size, size_t, private_aesni_cbc_t *this) { return this->key_size; } METHOD(crypter_t, set_key, bool, private_aesni_cbc_t *this, chunk_t key) { if (key.len != this->key_size) { return FALSE; } DESTROY_IF(this->ekey); DESTROY_IF(this->dkey); this->ekey = aesni_key_create(TRUE, key); this->dkey = aesni_key_create(FALSE, key); return this->ekey && this->dkey; } METHOD(crypter_t, destroy, void, private_aesni_cbc_t *this) { DESTROY_IF(this->ekey); DESTROY_IF(this->dkey); free(this); } /** * See header */ aesni_cbc_t *aesni_cbc_create(encryption_algorithm_t algo, size_t key_size) { private_aesni_cbc_t *this; if (algo != ENCR_AES_CBC) { return NULL; } switch (key_size) { case 0: key_size = 16; break; case 16: case 24: case 32: break; default: return NULL; } INIT(this, .public = { .crypter = { .encrypt = _encrypt, .decrypt = _decrypt, .get_block_size = _get_block_size, .get_iv_size = _get_iv_size, .get_key_size = _get_key_size, .set_key = _set_key, .destroy = _destroy, }, }, .key_size = key_size, ); switch (key_size) { case 16: this->encrypt = encrypt_cbc128; this->decrypt = decrypt_cbc128; break; case 24: this->encrypt = encrypt_cbc192; this->decrypt = decrypt_cbc192; break; case 32: this->encrypt = encrypt_cbc256; this->decrypt = decrypt_cbc256; break; } return &this->public; }