| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * FIPS140 randomness tests |
| 4 | * |
| 5 | * (c) 2000 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of Catacomb. |
| 11 | * |
| 12 | * Catacomb is free software; you can redistribute it and/or modify |
| 13 | * it under the terms of the GNU Library General Public License as |
| 14 | * published by the Free Software Foundation; either version 2 of the |
| 15 | * License, or (at your option) any later version. |
| 16 | * |
| 17 | * Catacomb is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU Library General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU Library General Public |
| 23 | * License along with Catacomb; if not, write to the Free |
| 24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
| 25 | * MA 02111-1307, USA. |
| 26 | */ |
| 27 | |
| 28 | /*----- Header files ------------------------------------------------------*/ |
| 29 | |
| 30 | #include <mLib/bits.h> |
| 31 | |
| 32 | #include "fipstest.h" |
| 33 | |
| 34 | /*----- Main code ---------------------------------------------------------*/ |
| 35 | |
| 36 | /* --- @monobit@ --- * |
| 37 | * |
| 38 | * Arguments: @const octet *p@ = pointer to buffer |
| 39 | * |
| 40 | * Returns: Zero if OK, @FIPSTEST_MONOBIT@ on failure. |
| 41 | * |
| 42 | * Use: Performs the monobit test on a buffer of data. If %$n_1$% is |
| 43 | * the number of 1 bits in the buffer, then the monobit test is |
| 44 | * passed when %$9654 < n_1 < 10346$%. |
| 45 | */ |
| 46 | |
| 47 | static unsigned monobit(const octet *p) |
| 48 | { |
| 49 | unsigned n1 = 0; |
| 50 | unsigned i, j; |
| 51 | |
| 52 | for (i = 0; i < FIPSTEST_BUFSZ; i++) { |
| 53 | octet x = p[i]; |
| 54 | for (j = 0; j < 8; j++) { |
| 55 | if (x & 1) |
| 56 | n1++; |
| 57 | x >>= 1; |
| 58 | } |
| 59 | } |
| 60 | |
| 61 | if (9725 >= n1 || n1 >= 10275) |
| 62 | return (FIPSTEST_MONOBIT); |
| 63 | return (0); |
| 64 | } |
| 65 | |
| 66 | /* --- @poker@ --- * |
| 67 | * |
| 68 | * Arguments: @const octet *p@ = pointer to buffer |
| 69 | * |
| 70 | * Returns: Zero if OK, @FIPSTEST_POKER@ on failure. |
| 71 | * |
| 72 | * Use: Performs the poker test on a buffer of data. The buffer is |
| 73 | * divided into 4-bit nibbles %$x_i$%. If |
| 74 | * %$f(x) = \sum_{x_i = x} 1$% is the frequency of each nibble, |
| 75 | * then the test is passed if |
| 76 | * %$2.16 < 16/5000 \sum_i f(i)^2 - 5000 < 46.17$%. |
| 77 | */ |
| 78 | |
| 79 | static unsigned poker(const octet *p) |
| 80 | { |
| 81 | unsigned long f[16] = { 0 }; |
| 82 | unsigned i; |
| 83 | unsigned long q = 0; |
| 84 | |
| 85 | /* --- Compute the frequencies --- */ |
| 86 | |
| 87 | for (i = 0; i < FIPSTEST_BUFSZ; i++) { |
| 88 | octet x = p[i]; |
| 89 | f[x & 0xf]++; |
| 90 | f[(x >> 4) & 0xf]++; |
| 91 | } |
| 92 | |
| 93 | /* --- Now do the comparison --- * |
| 94 | * |
| 95 | * This can be simplified. Multiply through the inequality by 5000 and |
| 96 | * we get %$5150 < 16 \sum_i f(i)^2 - 5000^2 < 287000$%. |
| 97 | */ |
| 98 | |
| 99 | for (i = 0; i < 16; i++) |
| 100 | q += f[i] * f[i]; |
| 101 | q <<= 4; |
| 102 | q -= 5000ul * 5000ul; |
| 103 | |
| 104 | if (10800 >= q || q >= 230850) |
| 105 | return (FIPSTEST_POKER); |
| 106 | return (0); |
| 107 | } |
| 108 | |
| 109 | /* --- @runs@ --- * |
| 110 | * |
| 111 | * Arguments: @const octet *p@ = pointer to buffer |
| 112 | * |
| 113 | * Returns: Zero for success, @FIPSTEST_RUNS@ or @FIPSTEST_LONGRUNS@ on |
| 114 | * failure. |
| 115 | * |
| 116 | * Use: Performs the runs and long runs tests. The frequency of each |
| 117 | * `run', or sequence of equal bits, is counted and tested. |
| 118 | */ |
| 119 | |
| 120 | static unsigned runs(const octet *p) |
| 121 | { |
| 122 | unsigned rc = 0; |
| 123 | unsigned i, j; |
| 124 | unsigned r = 0; |
| 125 | unsigned bb = 0; |
| 126 | unsigned f[2][6] = { { 0 } }; |
| 127 | |
| 128 | /* --- Count the run lengths --- */ |
| 129 | |
| 130 | for (i = 0; i < FIPSTEST_BUFSZ; i++) { |
| 131 | octet x = p[i]; |
| 132 | for (j = 0; j < 8; j++) { |
| 133 | unsigned b = x & 1; |
| 134 | x >>= 1; |
| 135 | if (b == bb) |
| 136 | r++; |
| 137 | else { |
| 138 | if (r) { |
| 139 | if (r >= 34) |
| 140 | rc |= FIPSTEST_LONGRUNS; |
| 141 | if (r > 6) |
| 142 | r = 6; |
| 143 | f[bb][r - 1]++; |
| 144 | } |
| 145 | r = 1; |
| 146 | bb = b; |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | |
| 151 | if (r >= 26) |
| 152 | rc |= FIPSTEST_LONGRUNS; |
| 153 | if (r > 6) |
| 154 | r = 6; |
| 155 | f[bb][r - 1]++; |
| 156 | |
| 157 | /* --- Check the results --- */ |
| 158 | |
| 159 | if (2343 > f[0][0] || f[0][0] > 2657 || 2343 > f[1][0] || f[1][0] > 2657 || |
| 160 | 1135 > f[0][1] || f[0][1] > 1365 || 1135 > f[1][1] || f[1][1] > 1365 || |
| 161 | 542 > f[0][2] || f[0][2] > 708 || 542 > f[1][2] || f[1][2] > 708 || |
| 162 | 251 > f[0][3] || f[0][3] > 373 || 251 > f[1][3] || f[1][3] > 373 || |
| 163 | 111 > f[0][4] || f[0][4] > 201 || 111 > f[1][4] || f[1][4] > 201 || |
| 164 | 111 > f[0][5] || f[0][5] > 201 || 111 > f[1][5] || f[1][5] > 201) |
| 165 | rc |= FIPSTEST_RUNS; |
| 166 | |
| 167 | return (rc); |
| 168 | } |
| 169 | |
| 170 | /* --- @fipstest@ --- * |
| 171 | * |
| 172 | * Arguments: @const octet *p@ = pointer to a buffer of @FIPSTEST_BUFSZ@ |
| 173 | * bytes |
| 174 | * |
| 175 | * Returns: Zero if OK, or a bitmask of failed tests. |
| 176 | * |
| 177 | * Use: Performs the FIPS140 randomness tests on a block of data. |
| 178 | */ |
| 179 | |
| 180 | unsigned fipstest(const octet *p) |
| 181 | { |
| 182 | unsigned rc = 0; |
| 183 | rc |= monobit(p); |
| 184 | rc |= poker(p); |
| 185 | rc |= runs(p); |
| 186 | return (rc); |
| 187 | } |
| 188 | |
| 189 | /*----- That's all, folks -------------------------------------------------*/ |