summaryrefslogtreecommitdiff
path: root/srtp/crypto/cipher/aes_cbc.c
diff options
context:
space:
mode:
authorErwin Nindl <nine@wirdorange.org>2007-06-22 13:59:20 +0000
committerErwin Nindl <nine@wirdorange.org>2007-06-22 13:59:20 +0000
commit0275479cb56c7f562f3513fef66c83fc44d1d8c9 (patch)
treef6fbb703cebf62d18b05e2a5e7591ac08c5b6702 /srtp/crypto/cipher/aes_cbc.c
parentsatp internet draft 00 final ietf version (diff)
added libsrtp to svn
Diffstat (limited to 'srtp/crypto/cipher/aes_cbc.c')
-rw-r--r--srtp/crypto/cipher/aes_cbc.c444
1 files changed, 444 insertions, 0 deletions
diff --git a/srtp/crypto/cipher/aes_cbc.c b/srtp/crypto/cipher/aes_cbc.c
new file mode 100644
index 0000000..8fc6a32
--- /dev/null
+++ b/srtp/crypto/cipher/aes_cbc.c
@@ -0,0 +1,444 @@
+/*
+ * 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) {
+ 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)
+ return err_status_bad_param;
+
+ /* allocate memory a cipher of type aes_icm */
+ 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,
+ cipher_direction_t dir) {
+ v128_t tmp_key;
+
+ /* set tmp_key (for alignment) */
+ v128_copy_octet_string(&tmp_key, key);
+
+ debug_print(mod_aes_cbc,
+ "key: %s", v128_hex_string(&tmp_key));
+
+ /* expand key for the appropriate direction */
+ switch (dir) {
+ case (direction_encrypt):
+ aes_expand_encryption_key(&tmp_key, c->expanded_key);
+ break;
+ case (direction_decrypt):
+ aes_expand_decryption_key(&tmp_key, c->expanded_key);
+ break;
+ default:
+ return err_status_bad_param;
+ }
+
+
+ return err_status_ok;
+}
+
+
+err_status_t
+aes_cbc_set_iv(aes_cbc_ctx_t *c, void *iv) {
+ 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));
+
+ 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 A; 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 */
+ 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 */
+ &aes_cbc_test_case_0 /* 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_encrypt_func_t) aes_cbc_nist_encrypt,
+ (cipher_decrypt_func_t) aes_cbc_nist_decrypt,
+ (cipher_set_iv_func_t) aes_cbc_set_iv,
+ (char *) aes_cbc_description,
+ (int) 0, /* instance count */
+ (cipher_test_case_t *) &aes_cbc_test_case_0,
+ (debug_module_t *) &mod_aes_cbc
+};
+
+