summaryrefslogtreecommitdiff
path: root/srtp/tables/aes_tables.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/tables/aes_tables.c
parentsatp internet draft 00 final ietf version (diff)
added libsrtp to svn
Diffstat (limited to 'srtp/tables/aes_tables.c')
-rw-r--r--srtp/tables/aes_tables.c346
1 files changed, 346 insertions, 0 deletions
diff --git a/srtp/tables/aes_tables.c b/srtp/tables/aes_tables.c
new file mode 100644
index 0000000..b2bc1d7
--- /dev/null
+++ b/srtp/tables/aes_tables.c
@@ -0,0 +1,346 @@
+/*
+ * aes_tables.c
+ *
+ * generate tables for the AES cipher
+ *
+ * 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 <stdio.h>
+#include "gf2_8.h"
+#include "crypto_math.h"
+
+
+unsigned char aes_sbox[256];
+
+unsigned char aes_inv_sbox[256];
+
+uint32_t T0[256], T1[256], T2[256], T3[256], T4[256];
+
+
+#define AES_INVERSE_TEST 0 /* set to 1 to test forward/backwards aes */
+
+/* functions for precomputing AES values */
+
+/*
+ * A[] is the 8 x 8 binary matrix (represented as an array of columns,
+ * where each column is an octet) which defines the affine
+ * transformation used in the AES substitution table (Section
+ * 4.2.1 of the spec).
+ */
+
+uint8_t A[8] = { 31, 62, 124, 248, 241, 227, 199, 143 };
+
+/*
+ * b is the 8 bit vector (represented as an octet) used in the affine
+ * transform described above.
+ */
+
+uint8_t b = 99;
+
+
+void
+aes_init_sbox(void) {
+ unsigned int i;
+ uint8_t x;
+
+ for (i=0; i < 256; i++) {
+ x = gf2_8_compute_inverse((gf2_8)i);
+ x = A_times_x_plus_b(A, x, b);
+ aes_sbox[i] = x;
+ aes_inv_sbox[x] = i;
+ }
+}
+
+void
+aes_compute_tables(void) {
+ int i;
+ uint32_t x1, x2, x3;
+ v32_t tmp;
+
+ /* initialize substitution table */
+ aes_init_sbox();
+
+ /* combine sbox with linear operations to form 8-bit to 32-bit tables */
+ for (i=0; i < 256; i++) {
+ x1 = aes_sbox[i];
+ x2 = gf2_8_shift(x1);
+ x3 = x2 ^ x1;
+
+ tmp.v8[0] = x2;
+ tmp.v8[1] = x1;
+ tmp.v8[2] = x1;
+ tmp.v8[3] = x3;
+ T0[i] = tmp.value;
+
+ tmp.v8[0] = x3;
+ tmp.v8[1] = x2;
+ tmp.v8[2] = x1;
+ tmp.v8[3] = x1;
+ T1[i] = tmp.value;
+
+ tmp.v8[0] = x1;
+ tmp.v8[1] = x3;
+ tmp.v8[2] = x2;
+ tmp.v8[3] = x1;
+ T2[i] = tmp.value;
+
+ tmp.v8[0] = x1;
+ tmp.v8[1] = x1;
+ tmp.v8[2] = x3;
+ tmp.v8[3] = x2;
+ T3[i] = tmp.value;
+
+ }
+}
+
+
+/*
+ * the tables U0, U1, U2, U3 implement the aes operations invSubBytes,
+ * invMixColumns, and invShiftRows
+ */
+
+uint32_t U0[256], U1[256], U2[256], U3[256], U4[256];
+
+extern uint8_t aes_inv_sbox[256];
+
+void
+aes_compute_inv_tables(void) {
+ int i;
+ uint8_t x, xe, x9, xd, xb;
+ v32_t tmp;
+
+ /* combine sbox with linear operations to form 8-bit to 32-bit tables */
+ for (i=0; i < 256; i++) {
+ x = aes_inv_sbox[i];
+
+ xe = gf2_8_multiply(0x0e, x);
+ x9 = gf2_8_multiply(0x09, x);
+ xd = gf2_8_multiply(0x0d, x);
+ xb = gf2_8_multiply(0x0b, x);
+
+ tmp.v8[0] = xe;
+ tmp.v8[1] = x9;
+ tmp.v8[2] = xd;
+ tmp.v8[3] = xb;
+ U0[i] = tmp.value;
+
+ tmp.v8[0] = xb;
+ tmp.v8[1] = xe;
+ tmp.v8[2] = x9;
+ tmp.v8[3] = xd;
+ U1[i] = tmp.value;
+
+ tmp.v8[0] = xd;
+ tmp.v8[1] = xb;
+ tmp.v8[2] = xe;
+ tmp.v8[3] = x9;
+ U2[i] = tmp.value;
+
+ tmp.v8[0] = x9;
+ tmp.v8[1] = xd;
+ tmp.v8[2] = xb;
+ tmp.v8[3] = xe;
+ U3[i] = tmp.value;
+
+ tmp.v8[0] = tmp.v8[1] = tmp.v8[2] = tmp.v8[3] = x;
+ U4[i] = tmp.value;
+ }
+}
+
+
+/*
+ * aes_test_inverse() returns err_status_ok if aes
+ * encryption and decryption are true inverses of each other, and
+ * returns err_status_algo_fail otherwise
+ */
+
+#include "err.h"
+
+err_status_t
+aes_test_inverse(void);
+
+#define TABLES_32BIT 1
+
+int
+main(void) {
+ int i;
+
+ aes_init_sbox();
+ aes_compute_inv_tables();
+
+#if TABLES_32BIT
+ printf("uint32_t U0 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%0x, ", U0[i]);
+ }
+ printf("\n}\n");
+
+ printf("uint32_t U1 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%x, ", U1[i]);
+ }
+ printf("\n}\n");
+
+ printf("uint32_t U2 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%x, ", U2[i]);
+ }
+ printf("\n}\n");
+
+ printf("uint32_t U3 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%x, ", U3[i]);
+ }
+ printf("\n}\n");
+
+ printf("uint32_t U4 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%x, ", U4[i]);
+ }
+ printf("\n}\n");
+
+#else
+
+ printf("uint32_t U0 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%lx, ", U0[i]);
+ }
+ printf("\n}\n");
+
+ printf("uint32_t U1 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%lx, ", U1[i]);
+ }
+ printf("\n}\n");
+
+ printf("uint32_t U2 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%lx, ", U2[i]);
+ }
+ printf("\n}\n");
+
+ printf("uint32_t U3 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%lx, ", U3[i]);
+ }
+ printf("\n}\n");
+
+ printf("uint32_t U4 = {");
+ for (i=0; i < 256; i++) {
+ if ((i % 4) == 0)
+ printf("\n");
+ printf("0x%lx, ", U4[i]);
+ }
+ printf("\n}\n");
+
+
+#endif /* TABLES_32BIT */
+
+
+#if AES_INVERSE_TEST
+ /*
+ * test that aes_encrypt and aes_decrypt are actually
+ * inverses of each other
+ */
+
+ printf("aes inverse test: ");
+ if (aes_test_inverse() == err_status_ok)
+ printf("passed\n");
+ else {
+ printf("failed\n");
+ exit(1);
+ }
+#endif
+
+ return 0;
+}
+
+#if AES_INVERSE_TEST
+
+err_status_t
+aes_test_inverse(void) {
+ v128_t x, y;
+ aes_expanded_key_t expanded_key, decrypt_key;
+ uint8_t plaintext[16] = {
+ 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
+ 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
+ };
+ uint8_t key[16] = {
+ 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+ 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
+ };
+ v128_t k;
+ v128_set_to_zero(&x);
+
+ v128_copy_octet_string(&k, key);
+ v128_copy_octet_string(&x, plaintext);
+ aes_expand_encryption_key(k, expanded_key);
+ aes_expand_decryption_key(k, decrypt_key);
+ aes_encrypt(&x, expanded_key);
+ aes_decrypt(&x, decrypt_key);
+
+ /* compare to expected value then report */
+ v128_copy_octet_string(&y, plaintext);
+
+ if (v128_is_eq(&x, &y))
+ return err_status_ok;
+ return err_status_algo_fail;
+
+}
+
+#endif