2 * Utilities for constant-time cryptography.
4 * Author: Emilia Kasper (emilia@openssl.org)
5 * Based on previous work by Bodo Moeller, Emilia Kasper, Adam Langley
7 * ====================================================================
8 * Copyright (c) 2014 The OpenSSL Project. All rights reserved.
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 * must display the following acknowledgement:
20 * "This product includes cryptographic software written by
21 * Eric Young (eay@cryptsoft.com)"
22 * The word 'cryptographic' can be left out if the rouines from the library
23 * being used are not cryptographic related :-).
24 * 4. If you include any Windows specific code (or a derivative thereof) from
25 * the apps directory (application code) you must include an acknowledgement:
26 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
28 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
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30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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40 * The licence and distribution terms for any publically available version or
41 * derivative of this code cannot be changed. i.e. this code cannot simply be
42 * copied and put under another distribution licence
43 * [including the GNU Public Licence.]
46 #include "internal/constant_time_locl.h"
53 static const unsigned int CONSTTIME_TRUE = (unsigned)(~0);
54 static const unsigned int CONSTTIME_FALSE = 0;
55 static const unsigned char CONSTTIME_TRUE_8 = 0xff;
56 static const unsigned char CONSTTIME_FALSE_8 = 0;
58 static int test_binary_op(unsigned int (*op) (unsigned int a, unsigned int b),
59 const char *op_name, unsigned int a, unsigned int b,
62 unsigned c = op(a, b);
63 if (is_true && c != CONSTTIME_TRUE) {
64 fprintf(stderr, "Test failed for %s(%du, %du): expected %du "
65 "(TRUE), got %du\n", op_name, a, b, CONSTTIME_TRUE, c);
67 } else if (!is_true && c != CONSTTIME_FALSE) {
68 fprintf(stderr, "Test failed for %s(%du, %du): expected %du "
69 "(FALSE), got %du\n", op_name, a, b, CONSTTIME_FALSE, c);
75 static int test_binary_op_8(unsigned
76 char (*op) (unsigned int a, unsigned int b),
77 const char *op_name, unsigned int a,
78 unsigned int b, int is_true)
80 unsigned char c = op(a, b);
81 if (is_true && c != CONSTTIME_TRUE_8) {
82 fprintf(stderr, "Test failed for %s(%du, %du): expected %u "
83 "(TRUE), got %u\n", op_name, a, b, CONSTTIME_TRUE_8, c);
85 } else if (!is_true && c != CONSTTIME_FALSE_8) {
86 fprintf(stderr, "Test failed for %s(%du, %du): expected %u "
87 "(FALSE), got %u\n", op_name, a, b, CONSTTIME_FALSE_8, c);
93 static int test_is_zero(unsigned int a)
95 unsigned int c = constant_time_is_zero(a);
96 if (a == 0 && c != CONSTTIME_TRUE) {
97 fprintf(stderr, "Test failed for constant_time_is_zero(%du): "
98 "expected %du (TRUE), got %du\n", a, CONSTTIME_TRUE, c);
100 } else if (a != 0 && c != CONSTTIME_FALSE) {
101 fprintf(stderr, "Test failed for constant_time_is_zero(%du): "
102 "expected %du (FALSE), got %du\n", a, CONSTTIME_FALSE, c);
108 static int test_is_zero_8(unsigned int a)
110 unsigned char c = constant_time_is_zero_8(a);
111 if (a == 0 && c != CONSTTIME_TRUE_8) {
112 fprintf(stderr, "Test failed for constant_time_is_zero(%du): "
113 "expected %u (TRUE), got %u\n", a, CONSTTIME_TRUE_8, c);
115 } else if (a != 0 && c != CONSTTIME_FALSE) {
116 fprintf(stderr, "Test failed for constant_time_is_zero(%du): "
117 "expected %u (FALSE), got %u\n", a, CONSTTIME_FALSE_8, c);
123 static int test_select(unsigned int a, unsigned int b)
125 unsigned int selected = constant_time_select(CONSTTIME_TRUE, a, b);
127 fprintf(stderr, "Test failed for constant_time_select(%du, %du,"
128 "%du): expected %du(first value), got %du\n",
129 CONSTTIME_TRUE, a, b, a, selected);
132 selected = constant_time_select(CONSTTIME_FALSE, a, b);
134 fprintf(stderr, "Test failed for constant_time_select(%du, %du,"
135 "%du): expected %du(second value), got %du\n",
136 CONSTTIME_FALSE, a, b, b, selected);
142 static int test_select_8(unsigned char a, unsigned char b)
144 unsigned char selected = constant_time_select_8(CONSTTIME_TRUE_8, a, b);
146 fprintf(stderr, "Test failed for constant_time_select(%u, %u,"
147 "%u): expected %u(first value), got %u\n",
148 CONSTTIME_TRUE, a, b, a, selected);
151 selected = constant_time_select_8(CONSTTIME_FALSE_8, a, b);
153 fprintf(stderr, "Test failed for constant_time_select(%u, %u,"
154 "%u): expected %u(second value), got %u\n",
155 CONSTTIME_FALSE, a, b, b, selected);
161 static int test_select_int(int a, int b)
163 int selected = constant_time_select_int(CONSTTIME_TRUE, a, b);
165 fprintf(stderr, "Test failed for constant_time_select(%du, %d,"
166 "%d): expected %d(first value), got %d\n",
167 CONSTTIME_TRUE, a, b, a, selected);
170 selected = constant_time_select_int(CONSTTIME_FALSE, a, b);
172 fprintf(stderr, "Test failed for constant_time_select(%du, %d,"
173 "%d): expected %d(second value), got %d\n",
174 CONSTTIME_FALSE, a, b, b, selected);
180 static int test_eq_int(int a, int b)
182 unsigned int equal = constant_time_eq_int(a, b);
183 if (a == b && equal != CONSTTIME_TRUE) {
184 fprintf(stderr, "Test failed for constant_time_eq_int(%d, %d): "
185 "expected %du(TRUE), got %du\n", a, b, CONSTTIME_TRUE, equal);
187 } else if (a != b && equal != CONSTTIME_FALSE) {
188 fprintf(stderr, "Test failed for constant_time_eq_int(%d, %d): "
189 "expected %du(FALSE), got %du\n",
190 a, b, CONSTTIME_FALSE, equal);
196 static int test_eq_int_8(int a, int b)
198 unsigned char equal = constant_time_eq_int_8(a, b);
199 if (a == b && equal != CONSTTIME_TRUE_8) {
200 fprintf(stderr, "Test failed for constant_time_eq_int_8(%d, %d): "
201 "expected %u(TRUE), got %u\n", a, b, CONSTTIME_TRUE_8, equal);
203 } else if (a != b && equal != CONSTTIME_FALSE_8) {
204 fprintf(stderr, "Test failed for constant_time_eq_int_8(%d, %d): "
205 "expected %u(FALSE), got %u\n",
206 a, b, CONSTTIME_FALSE_8, equal);
212 static unsigned int test_values[] =
213 { 0, 1, 1024, 12345, 32000, UINT_MAX / 2 - 1,
214 UINT_MAX / 2, UINT_MAX / 2 + 1, UINT_MAX - 1,
218 static unsigned char test_values_8[] =
219 { 0, 1, 2, 20, 32, 127, 128, 129, 255 };
221 static int signed_test_values[] = { 0, 1, -1, 1024, -1024, 12345, -12345,
222 32000, -32000, INT_MAX, INT_MIN, INT_MAX - 1,
226 int main(int argc, char *argv[])
228 unsigned int a, b, i, j;
231 int num_failed = 0, num_all = 0;
232 fprintf(stdout, "Testing constant time operations...\n");
234 for (i = 0; i < OSSL_NELEM(test_values); ++i) {
236 num_failed += test_is_zero(a);
237 num_failed += test_is_zero_8(a);
239 for (j = 0; j < OSSL_NELEM(test_values); ++j) {
241 num_failed += test_binary_op(&constant_time_lt,
242 "constant_time_lt", a, b, a < b);
243 num_failed += test_binary_op_8(&constant_time_lt_8,
244 "constant_time_lt_8", a, b, a < b);
245 num_failed += test_binary_op(&constant_time_lt,
246 "constant_time_lt_8", b, a, b < a);
247 num_failed += test_binary_op_8(&constant_time_lt_8,
248 "constant_time_lt_8", b, a, b < a);
249 num_failed += test_binary_op(&constant_time_ge,
250 "constant_time_ge", a, b, a >= b);
251 num_failed += test_binary_op_8(&constant_time_ge_8,
252 "constant_time_ge_8", a, b,
255 test_binary_op(&constant_time_ge, "constant_time_ge", b, a,
258 test_binary_op_8(&constant_time_ge_8, "constant_time_ge_8", b,
261 test_binary_op(&constant_time_eq, "constant_time_eq", a, b,
264 test_binary_op_8(&constant_time_eq_8, "constant_time_eq_8", a,
267 test_binary_op(&constant_time_eq, "constant_time_eq", b, a,
270 test_binary_op_8(&constant_time_eq_8, "constant_time_eq_8", b,
272 num_failed += test_select(a, b);
277 for (i = 0; i < OSSL_NELEM(signed_test_values); ++i) {
278 c = signed_test_values[i];
279 for (j = 0; j < OSSL_NELEM(signed_test_values); ++j) {
280 d = signed_test_values[j];
281 num_failed += test_select_int(c, d);
282 num_failed += test_eq_int(c, d);
283 num_failed += test_eq_int_8(c, d);
288 for (i = 0; i < sizeof(test_values_8); ++i) {
289 e = test_values_8[i];
290 for (j = 0; j < sizeof(test_values_8); ++j) {
291 f = test_values_8[j];
292 num_failed += test_select_8(e, f);
298 fprintf(stdout, "success (ran %d tests)\n", num_all);
301 fprintf(stdout, "%d of %d tests failed!\n", num_failed, num_all);