/* * aes_cbc.c * * AES Cipher Block Chaining Mode * * David A. McGrew * Cisco Systems, Inc. */ /* * * Copyright (c) 2001-2006, Cisco Systems, Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * * Neither the name of the Cisco Systems, Inc. nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED * OF THE POSSIBILITY OF SUCH DAMAGE. * */ #include "aes_cbc.h" #include "alloc.h" debug_module_t mod_aes_cbc = { 0, /* debugging is off by default */ "aes cbc" /* printable module name */ }; err_status_t aes_cbc_alloc(cipher_t **c, int key_len, int tlen) { extern cipher_type_t aes_cbc; uint8_t *pointer; int tmp; debug_print(mod_aes_cbc, "allocating cipher with key length %d", key_len); if (key_len != 16 && key_len != 24 && key_len != 32) return err_status_bad_param; /* allocate memory a cipher of type aes_cbc */ tmp = (sizeof(aes_cbc_ctx_t) + sizeof(cipher_t)); pointer = (uint8_t*)crypto_alloc(tmp); if (pointer == NULL) return err_status_alloc_fail; /* set pointers */ *c = (cipher_t *)pointer; (*c)->type = &aes_cbc; (*c)->state = pointer + sizeof(cipher_t); /* increment ref_count */ aes_cbc.ref_count++; /* set key size */ (*c)->key_len = key_len; return err_status_ok; } err_status_t aes_cbc_dealloc(cipher_t *c) { extern cipher_type_t aes_cbc; /* zeroize entire state*/ octet_string_set_to_zero((uint8_t *)c, sizeof(aes_cbc_ctx_t) + sizeof(cipher_t)); /* free memory */ crypto_free(c); /* decrement ref_count */ aes_cbc.ref_count--; return err_status_ok; } err_status_t aes_cbc_context_init(aes_cbc_ctx_t *c, const uint8_t *key, int key_len) { debug_print(mod_aes_cbc, "key: %s", octet_string_hex_string(key, key_len)); /* * Save the key until we have the IV later. We don't * know the direction until the IV is set. */ c->key_len = (key_len <= 32 ? key_len : 32); memcpy(c->key, key, c->key_len); return err_status_ok; } err_status_t aes_cbc_set_iv(aes_cbc_ctx_t *c, void *iv, int direction) { err_status_t status; int i; /* v128_t *input = iv; */ uint8_t *input = (uint8_t*) iv; /* set state and 'previous' block to iv */ for (i=0; i < 16; i++) c->previous.v8[i] = c->state.v8[i] = input[i]; debug_print(mod_aes_cbc, "setting iv: %s", v128_hex_string(&c->state)); /* expand key for the appropriate direction */ switch (direction) { case (direction_encrypt): status = aes_expand_encryption_key(c->key, c->key_len, &c->expanded_key); memset(c->key, 0, 32); if (status) return status; break; case (direction_decrypt): status = aes_expand_decryption_key(c->key, c->key_len, &c->expanded_key); memset(c->key, 0, 32); if (status) return status; break; default: return err_status_bad_param; } return err_status_ok; } err_status_t aes_cbc_encrypt(aes_cbc_ctx_t *c, unsigned char *data, unsigned int *bytes_in_data) { int i; unsigned char *input = data; /* pointer to data being read */ unsigned char *output = data; /* pointer to data being written */ int bytes_to_encr = *bytes_in_data; /* * verify that we're 16-octet aligned */ if (*bytes_in_data & 0xf) return err_status_bad_param; /* * note that we assume that the initialization vector has already * been set, e.g. by calling aes_cbc_set_iv() */ debug_print(mod_aes_cbc, "iv: %s", v128_hex_string(&c->state)); /* * loop over plaintext blocks, exoring state into plaintext then * encrypting and writing to output */ while (bytes_to_encr > 0) { /* exor plaintext into state */ for (i=0; i < 16; i++) c->state.v8[i] ^= *input++; debug_print(mod_aes_cbc, "inblock: %s", v128_hex_string(&c->state)); aes_encrypt(&c->state, &c->expanded_key); debug_print(mod_aes_cbc, "outblock: %s", v128_hex_string(&c->state)); /* copy ciphertext to output */ for (i=0; i < 16; i++) *output++ = c->state.v8[i]; bytes_to_encr -= 16; } return err_status_ok; } err_status_t aes_cbc_decrypt(aes_cbc_ctx_t *c, unsigned char *data, unsigned int *bytes_in_data) { int i; v128_t state, previous; unsigned char *input = data; /* pointer to data being read */ unsigned char *output = data; /* pointer to data being written */ int bytes_to_encr = *bytes_in_data; uint8_t tmp; /* * verify that we're 16-octet aligned */ if (*bytes_in_data & 0x0f) return err_status_bad_param; /* set 'previous' block to iv*/ for (i=0; i < 16; i++) { previous.v8[i] = c->previous.v8[i]; } debug_print(mod_aes_cbc, "iv: %s", v128_hex_string(&previous)); /* * loop over ciphertext blocks, decrypting then exoring with state * then writing plaintext to output */ while (bytes_to_encr > 0) { /* set state to ciphertext input block */ for (i=0; i < 16; i++) { state.v8[i] = *input++; } debug_print(mod_aes_cbc, "inblock: %s", v128_hex_string(&state)); /* decrypt state */ aes_decrypt(&state, &c->expanded_key); debug_print(mod_aes_cbc, "outblock: %s", v128_hex_string(&state)); /* * exor previous ciphertext block out of plaintext, and write new * plaintext block to output, while copying old ciphertext block * to the 'previous' block */ for (i=0; i < 16; i++) { tmp = *output; *output++ = state.v8[i] ^ previous.v8[i]; previous.v8[i] = tmp; } bytes_to_encr -= 16; } return err_status_ok; } err_status_t aes_cbc_nist_encrypt(aes_cbc_ctx_t *c, unsigned char *data, unsigned int *bytes_in_data) { int i; unsigned char *pad_start; int num_pad_bytes; err_status_t status; /* * determine the number of padding bytes that we need to add - * this value is always between 1 and 16, inclusive. */ num_pad_bytes = 16 - (*bytes_in_data & 0xf); pad_start = data; pad_start += *bytes_in_data; *pad_start++ = 0xa0; for (i=0; i < num_pad_bytes; i++) *pad_start++ = 0x00; /* * increment the data size */ *bytes_in_data += num_pad_bytes; /* * now cbc encrypt the padded data */ status = aes_cbc_encrypt(c, data, bytes_in_data); if (status) return status; return err_status_ok; } err_status_t aes_cbc_nist_decrypt(aes_cbc_ctx_t *c, unsigned char *data, unsigned int *bytes_in_data) { unsigned char *pad_end; int num_pad_bytes; err_status_t status; /* * cbc decrypt the padded data */ status = aes_cbc_decrypt(c, data, bytes_in_data); if (status) return status; /* * determine the number of padding bytes in the decrypted plaintext * - this value is always between 1 and 16, inclusive. */ num_pad_bytes = 1; pad_end = data + (*bytes_in_data - 1); while (*pad_end != 0xa0) { /* note: should check padding correctness */ pad_end--; num_pad_bytes++; } /* decrement data size */ *bytes_in_data -= num_pad_bytes; return err_status_ok; } char aes_cbc_description[] = "aes cipher block chaining (cbc) mode"; /* * Test case 0 is derived from FIPS 197 Appendix C; it uses an * all-zero IV, so that the first block encryption matches the test * case in that appendix. This property provides a check of the base * AES encryption and decryption algorithms; if CBC fails on some * particular platform, then you should print out AES intermediate * data and compare with the detailed info provided in that appendix. * */ uint8_t aes_cbc_test_case_0_key[16] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f }; uint8_t aes_cbc_test_case_0_plaintext[64] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }; uint8_t aes_cbc_test_case_0_ciphertext[80] = { 0x69, 0xc4, 0xe0, 0xd8, 0x6a, 0x7b, 0x04, 0x30, 0xd8, 0xcd, 0xb7, 0x80, 0x70, 0xb4, 0xc5, 0x5a, 0x03, 0x35, 0xed, 0x27, 0x67, 0xf2, 0x6d, 0xf1, 0x64, 0x83, 0x2e, 0x23, 0x44, 0x38, 0x70, 0x8b }; uint8_t aes_cbc_test_case_0_iv[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; cipher_test_case_t aes_cbc_test_case_0 = { 16, /* octets in key */ aes_cbc_test_case_0_key, /* key */ aes_cbc_test_case_0_iv, /* initialization vector */ 16, /* octets in plaintext */ aes_cbc_test_case_0_plaintext, /* plaintext */ 32, /* octets in ciphertext */ aes_cbc_test_case_0_ciphertext, /* ciphertext */ 0, NULL, 0, NULL /* pointer to next testcase */ }; /* * this test case is taken directly from Appendix F.2 of NIST Special * Publication SP 800-38A */ uint8_t aes_cbc_test_case_1_key[16] = { 0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6, 0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c, }; uint8_t aes_cbc_test_case_1_plaintext[64] = { 0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96, 0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a, 0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c, 0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51, 0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11, 0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef, 0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17, 0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10 }; uint8_t aes_cbc_test_case_1_ciphertext[80] = { 0x76, 0x49, 0xab, 0xac, 0x81, 0x19, 0xb2, 0x46, 0xce, 0xe9, 0x8e, 0x9b, 0x12, 0xe9, 0x19, 0x7d, 0x50, 0x86, 0xcb, 0x9b, 0x50, 0x72, 0x19, 0xee, 0x95, 0xdb, 0x11, 0x3a, 0x91, 0x76, 0x78, 0xb2, 0x73, 0xbe, 0xd6, 0xb8, 0xe3, 0xc1, 0x74, 0x3b, 0x71, 0x16, 0xe6, 0x9e, 0x22, 0x22, 0x95, 0x16, 0x3f, 0xf1, 0xca, 0xa1, 0x68, 0x1f, 0xac, 0x09, 0x12, 0x0e, 0xca, 0x30, 0x75, 0x86, 0xe1, 0xa7, 0x39, 0x34, 0x07, 0x03, 0x36, 0xd0, 0x77, 0x99, 0xe0, 0xc4, 0x2f, 0xdd, 0xa8, 0xdf, 0x4c, 0xa3 }; uint8_t aes_cbc_test_case_1_iv[16] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f }; cipher_test_case_t aes_cbc_test_case_1 = { 16, /* octets in key */ aes_cbc_test_case_1_key, /* key */ aes_cbc_test_case_1_iv, /* initialization vector */ 64, /* octets in plaintext */ aes_cbc_test_case_1_plaintext, /* plaintext */ 80, /* octets in ciphertext */ aes_cbc_test_case_1_ciphertext, /* ciphertext */ 0, NULL, 0, &aes_cbc_test_case_0 /* pointer to next testcase */ }; /* * Test case 2 is like test case 0, but for 256-bit keys. (FIPS 197 * appendix C.3). */ uint8_t aes_cbc_test_case_2_key[32] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f }; uint8_t aes_cbc_test_case_2_plaintext[64] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff }; uint8_t aes_cbc_test_case_2_ciphertext[80] = { 0x8e, 0xa2, 0xb7, 0xca, 0x51, 0x67, 0x45, 0xbf, 0xea, 0xfc, 0x49, 0x90, 0x4b, 0x49, 0x60, 0x89, 0x72, 0x72, 0x6e, 0xe7, 0x71, 0x39, 0xbf, 0x11, 0xe5, 0x40, 0xe2, 0x7c, 0x54, 0x65, 0x1d, 0xee }; uint8_t aes_cbc_test_case_2_iv[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 }; cipher_test_case_t aes_cbc_test_case_2 = { 32, /* octets in key */ aes_cbc_test_case_2_key, /* key */ aes_cbc_test_case_2_iv, /* initialization vector */ 16, /* octets in plaintext */ aes_cbc_test_case_2_plaintext, /* plaintext */ 32, /* octets in ciphertext */ aes_cbc_test_case_2_ciphertext, /* ciphertext */ 0, NULL, 0, &aes_cbc_test_case_1 /* pointer to next testcase */ }; /* * this test case is taken directly from Appendix F.2 of NIST Special * Publication SP 800-38A */ uint8_t aes_cbc_test_case_3_key[32] = { 0x60, 0x3d, 0xeb, 0x10, 0x15, 0xca, 0x71, 0xbe, 0x2b, 0x73, 0xae, 0xf0, 0x85, 0x7d, 0x77, 0x81, 0x1f, 0x35, 0x2c, 0x07, 0x3b, 0x61, 0x08, 0xd7, 0x2d, 0x98, 0x10, 0xa3, 0x09, 0x14, 0xdf, 0xf4 }; uint8_t aes_cbc_test_case_3_plaintext[64] = { 0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96, 0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a, 0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c, 0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51, 0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11, 0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef, 0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17, 0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10 }; uint8_t aes_cbc_test_case_3_ciphertext[80] = { 0xf5, 0x8c, 0x4c, 0x04, 0xd6, 0xe5, 0xf1, 0xba, 0x77, 0x9e, 0xab, 0xfb, 0x5f, 0x7b, 0xfb, 0xd6, 0x9c, 0xfc, 0x4e, 0x96, 0x7e, 0xdb, 0x80, 0x8d, 0x67, 0x9f, 0x77, 0x7b, 0xc6, 0x70, 0x2c, 0x7d, 0x39, 0xf2, 0x33, 0x69, 0xa9, 0xd9, 0xba, 0xcf, 0xa5, 0x30, 0xe2, 0x63, 0x04, 0x23, 0x14, 0x61, 0xb2, 0xeb, 0x05, 0xe2, 0xc3, 0x9b, 0xe9, 0xfc, 0xda, 0x6c, 0x19, 0x07, 0x8c, 0x6a, 0x9d, 0x1b, 0xfb, 0x98, 0x20, 0x2c, 0x45, 0xb2, 0xe4, 0xa0, 0x63, 0xc4, 0x68, 0xba, 0x84, 0x39, 0x16, 0x5a }; uint8_t aes_cbc_test_case_3_iv[16] = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f }; cipher_test_case_t aes_cbc_test_case_3 = { 32, /* octets in key */ aes_cbc_test_case_3_key, /* key */ aes_cbc_test_case_3_iv, /* initialization vector */ 64, /* octets in plaintext */ aes_cbc_test_case_3_plaintext, /* plaintext */ 80, /* octets in ciphertext */ aes_cbc_test_case_3_ciphertext, /* ciphertext */ 0, NULL, 0, &aes_cbc_test_case_2 /* pointer to next testcase */ }; cipher_type_t aes_cbc = { (cipher_alloc_func_t) aes_cbc_alloc, (cipher_dealloc_func_t) aes_cbc_dealloc, (cipher_init_func_t) aes_cbc_context_init, (cipher_set_aad_func_t) 0, (cipher_encrypt_func_t) aes_cbc_nist_encrypt, (cipher_decrypt_func_t) aes_cbc_nist_decrypt, (cipher_set_iv_func_t) aes_cbc_set_iv, (cipher_get_tag_func_t) 0, (char *) aes_cbc_description, (int) 0, /* instance count */ (cipher_test_case_t *) &aes_cbc_test_case_3, (debug_module_t *) &mod_aes_cbc, (cipher_type_id_t) AES_CBC };