X-Git-Url: https://git.distorted.org.uk/u/mdw/catacomb/blobdiff_plain/ba6e6b64033b1f9de49feccb5c9cd438354481f7..0f00dc4c8eb47e67bc0f148c2dd109f73a451e0a:/rand/fipstest.c

diff --git a/rand/fipstest.c b/rand/fipstest.c
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+/* -*-c-*-
+ *
+ * FIPS140 randomness tests
+ *
+ * (c) 2000 Straylight/Edgeware
+ */
+
+/*----- Licensing notice --------------------------------------------------*
+ *
+ * This file is part of Catacomb.
+ *
+ * Catacomb is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Library General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Catacomb is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with Catacomb; if not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+/*----- Header files ------------------------------------------------------*/
+
+#include <mLib/bits.h>
+
+#include "fipstest.h"
+
+/*----- Main code ---------------------------------------------------------*/
+
+/* --- @monobit@ --- *
+ *
+ * Arguments:	@const octet *p@ = pointer to buffer
+ *
+ * Returns:	Zero if OK, @FIPSTEST_MONOBIT@ on failure.
+ *
+ * Use:		Performs the monobit test on a buffer of data.  If %$n_1$% is
+ *		the number of 1 bits in the buffer, then the monobit test is
+ *		passed when %$9654 < n_1 < 10346$%.
+ */
+
+static unsigned monobit(const octet *p)
+{
+  unsigned n1 = 0;
+  unsigned i, j;
+
+  for (i = 0; i < FIPSTEST_BUFSZ; i++) {
+    octet x = p[i];
+    for (j = 0; j < 8; j++) {
+      if (x & 1)
+	n1++;
+      x >>= 1;
+    }
+  }
+
+  if (9725 >= n1 || n1 >= 10275)
+    return (FIPSTEST_MONOBIT);
+  return (0);
+}
+
+/* --- @poker@ --- *
+ *
+ * Arguments:	@const octet *p@ = pointer to buffer
+ *
+ * Returns:	Zero if OK, @FIPSTEST_POKER@ on failure.
+ *
+ * Use:		Performs the poker test on a buffer of data.  The buffer is
+ *		divided into 4-bit nibbles %$x_i$%.  If
+ *		%$f(x) = \sum_{x_i = x} 1$% is the frequency of each nibble,
+ *		then the test is passed if
+ *		%$2.16 < 16/5000 \sum_i f(i)^2 - 5000 < 46.17$%.
+ */
+
+static unsigned poker(const octet *p)
+{
+  unsigned long f[16] = { 0 };
+  unsigned i;
+  unsigned long q = 0;
+
+  /* --- Compute the frequencies --- */
+
+  for (i = 0; i < FIPSTEST_BUFSZ; i++) {
+    octet x = p[i];
+    f[x & 0xf]++;
+    f[(x >> 4) & 0xf]++;
+  }
+
+  /* --- Now do the comparison --- *
+   *
+   * This can be simplified.  Multiply through the inequality by 5000 and
+   * we get %$5150 < 16 \sum_i f(i)^2 - 5000^2 < 287000$%.
+   */
+
+  for (i = 0; i < 16; i++)
+    q += f[i] * f[i];
+  q <<= 4;
+  q -= 5000ul * 5000ul;
+
+  if (10800 >= q || q >= 230850)
+    return (FIPSTEST_POKER);
+  return (0);
+}
+
+/* --- @runs@ --- *
+ *
+ * Arguments:	@const octet *p@ = pointer to buffer
+ *
+ * Returns:	Zero for success, @FIPSTEST_RUNS@ or @FIPSTEST_LONGRUNS@ on
+ *		failure.
+ *
+ * Use:		Performs the runs and long runs tests.  The frequency of each
+ *		`run', or sequence of equal bits, is counted and tested.
+ */
+
+static unsigned runs(const octet *p)
+{
+  unsigned rc = 0;
+  unsigned i, j;
+  unsigned r = 0;
+  unsigned bb = 0;
+  unsigned f[2][6] = { { 0 } };
+
+  /* --- Count the run lengths --- */
+
+  for (i = 0; i < FIPSTEST_BUFSZ; i++) {
+    octet x = p[i];
+    for (j = 0; j < 8; j++) {
+      unsigned b = x & 1;
+      x >>= 1;
+      if (b == bb)
+	r++;
+      else {
+	if (r) {
+	  if (r >= 34)
+	    rc |= FIPSTEST_LONGRUNS;
+	  if (r > 6)
+	    r = 6;
+	  f[bb][r - 1]++;
+	}
+	r = 1;
+	bb = b;
+      }
+    }
+  }
+
+  if (r >= 26)
+    rc |= FIPSTEST_LONGRUNS;
+  if (r > 6)
+    r = 6;
+  f[bb][r - 1]++;
+
+  /* --- Check the results --- */
+
+  if (2343 > f[0][0] || f[0][0] > 2657 || 2343 > f[1][0] || f[1][0] > 2657 ||
+      1135 > f[0][1] || f[0][1] > 1365 || 1135 > f[1][1] || f[1][1] > 1365 ||
+       542 > f[0][2] || f[0][2] >  708 ||  542 > f[1][2] || f[1][2] >  708 ||
+       251 > f[0][3] || f[0][3] >  373 ||  251 > f[1][3] || f[1][3] >  373 ||
+       111 > f[0][4] || f[0][4] >  201 ||  111 > f[1][4] || f[1][4] >  201 ||
+       111 > f[0][5] || f[0][5] >  201 ||  111 > f[1][5] || f[1][5] >  201)
+    rc |= FIPSTEST_RUNS;
+
+  return (rc);
+}
+
+/* --- @fipstest@ --- *
+ *
+ * Arguments:	@const octet *p@ = pointer to a buffer of @FIPSTEST_BUFSZ@
+ *			bytes
+ *
+ * Returns:	Zero if OK, or a bitmask of failed tests.
+ *
+ * Use:		Performs the FIPS140 randomness tests on a block of data.
+ */
+
+unsigned fipstest(const octet *p)
+{
+  unsigned rc = 0;
+  rc |= monobit(p);
+  rc |= poker(p);
+  rc |= runs(p);
+  return (rc);
+}
+
+/*----- That's all, folks -------------------------------------------------*/