Index: crypto/math/stat.c |
diff --git a/crypto/math/stat.c b/crypto/math/stat.c |
new file mode 100644 |
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+++ b/crypto/math/stat.c |
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+/* |
+ * stats.c |
+ * |
+ * statistical tests |
+ * |
+ * 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. |
+ * |
+ */ |
+ |
+#ifdef HAVE_CONFIG_H |
+ #include <config.h> |
+#endif |
+ |
+#include "stat.h" |
+ |
+srtp_debug_module_t mod_stat = { |
+ 0, /* debugging is off by default */ |
+ (char *)"stat test" /* printable module name */ |
+}; |
+ |
+/* |
+ * each test assumes that 20,000 bits (2500 octets) of data is |
+ * provided as input |
+ */ |
+ |
+#define STAT_TEST_DATA_LEN 2500 |
+ |
+srtp_err_status_t |
+stat_test_monobit(uint8_t *data) { |
+ uint8_t *data_end = data + STAT_TEST_DATA_LEN; |
+ uint16_t ones_count; |
+ |
+ ones_count = 0; |
+ while (data < data_end) { |
+ ones_count += octet_get_weight(*data); |
+ data++; |
+ } |
+ |
+ debug_print(mod_stat, "bit count: %d", ones_count); |
+ |
+ if ((ones_count < 9725) || (ones_count > 10275)) |
+ return srtp_err_status_algo_fail; |
+ |
+ return srtp_err_status_ok; |
+} |
+ |
+srtp_err_status_t |
+stat_test_poker(uint8_t *data) { |
+ int i; |
+ uint8_t *data_end = data + STAT_TEST_DATA_LEN; |
+ double poker; |
+ uint16_t f[16] = { |
+ 0, 0, 0, 0, 0, 0, 0, 0, |
+ 0, 0, 0, 0, 0, 0, 0, 0 |
+ }; |
+ |
+ while (data < data_end) { |
+ f[*data & 0x0f]++; /* increment freq. count for low nibble */ |
+ f[(*data) >> 4]++; /* increment freq. count for high nibble */ |
+ data++; |
+ } |
+ |
+ poker = 0.0; |
+ for (i=0; i < 16; i++) |
+ poker += (double) f[i] * f[i]; |
+ |
+ poker *= (16.0 / 5000.0); |
+ poker -= 5000.0; |
+ |
+ debug_print(mod_stat, "poker test: %f\n", poker); |
+ |
+ if ((poker < 2.16) || (poker > 46.17)) |
+ return srtp_err_status_algo_fail; |
+ |
+ return srtp_err_status_ok; |
+} |
+ |
+ |
+/* |
+ * runs[i] holds the number of runs of size (i-1) |
+ */ |
+ |
+srtp_err_status_t |
+stat_test_runs(uint8_t *data) { |
+ uint8_t *data_end = data + STAT_TEST_DATA_LEN; |
+ uint16_t runs[6] = { 0, 0, 0, 0, 0, 0 }; |
+ uint16_t gaps[6] = { 0, 0, 0, 0, 0, 0 }; |
+ uint16_t lo_value[6] = { 2315, 1114, 527, 240, 103, 103 }; |
+ uint16_t hi_value[6] = { 2685, 1386, 723, 384, 209, 209 }; |
+ int state = 0; |
+ uint16_t mask; |
+ int i; |
+ |
+ /* |
+ * the state variable holds the number of bits in the |
+ * current run (or gap, if negative) |
+ */ |
+ |
+ while (data < data_end) { |
+ |
+ /* loop over the bits of this byte */ |
+ for (mask = 1; mask < 256; mask <<= 1) { |
+ if (*data & mask) { |
+ |
+ /* next bit is a one */ |
+ if (state > 0) { |
+ |
+ /* prefix is a run, so increment the run-count */ |
+ state++; |
+ |
+ /* check for long runs */ |
+ if (state > 25) { |
+ debug_print(mod_stat, ">25 runs: %d", state); |
+ return srtp_err_status_algo_fail; |
+ } |
+ |
+ } else if (state < 0) { |
+ |
+ /* prefix is a gap */ |
+ if (state < -25) { |
+ debug_print(mod_stat, ">25 gaps: %d", state); |
+ return srtp_err_status_algo_fail; /* long-runs test failed */ |
+ } |
+ if (state < -6) { |
+ state = -6; /* group together gaps > 5 */ |
+ } |
+ gaps[-1-state]++; /* increment gap count */ |
+ state = 1; /* set state at one set bit */ |
+ } else { |
+ |
+ /* state is zero; this happens only at initialization */ |
+ state = 1; |
+ } |
+ } else { |
+ |
+ /* next bit is a zero */ |
+ if (state > 0) { |
+ |
+ /* prefix is a run */ |
+ if (state > 25) { |
+ debug_print(mod_stat, ">25 runs (2): %d", state); |
+ return srtp_err_status_algo_fail; /* long-runs test failed */ |
+ } |
+ if (state > 6) { |
+ state = 6; /* group together runs > 5 */ |
+ } |
+ runs[state-1]++; /* increment run count */ |
+ state = -1; /* set state at one zero bit */ |
+ } else if (state < 0) { |
+ |
+ /* prefix is a gap, so increment gap-count (decrement state) */ |
+ state--; |
+ |
+ /* check for long gaps */ |
+ if (state < -25) { |
+ debug_print(mod_stat, ">25 gaps (2): %d", state); |
+ return srtp_err_status_algo_fail; |
+ } |
+ |
+ } else { |
+ |
+ /* state is zero; this happens only at initialization */ |
+ state = -1; |
+ } |
+ } |
+ } |
+ |
+ /* move along to next octet */ |
+ data++; |
+ } |
+ |
+ if (mod_stat.on) { |
+ debug_print(mod_stat, "runs test", NULL); |
+ for (i=0; i < 6; i++) |
+ debug_print(mod_stat, " runs[]: %d", runs[i]); |
+ for (i=0; i < 6; i++) |
+ debug_print(mod_stat, " gaps[]: %d", gaps[i]); |
+ } |
+ |
+ /* check run and gap counts against the fixed limits */ |
+ for (i=0; i < 6; i++) |
+ if ( (runs[i] < lo_value[i] ) || (runs[i] > hi_value[i]) |
+ || (gaps[i] < lo_value[i] ) || (gaps[i] > hi_value[i])) |
+ return srtp_err_status_algo_fail; |
+ |
+ |
+ return srtp_err_status_ok; |
+} |
+ |
+ |