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1 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
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2 * |
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3 * LibTomMath is a library that provides multiple-precision |
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4 * integer arithmetic as well as number theoretic functionality. |
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5 * |
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6 * The library was designed directly after the MPI library by |
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7 * Michael Fromberger but has been written from scratch with |
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8 * additional optimizations in place. |
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9 * |
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10 * The library is free for all purposes without any express |
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11 * guarantee it works. |
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12 * |
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13 * Tom St Denis, [email protected], http://math.libtomcrypt.org |
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14 */ |
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15 #include <tommath.h> |
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16 |
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17 /* this table gives the # of rabin miller trials for a prob of failure lower than 2^-96 */ |
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18 static const struct { |
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19 int k, t; |
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20 } sizes[] = { |
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21 { 128, 28 }, |
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22 { 256, 16 }, |
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23 { 384, 10 }, |
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24 { 512, 7 }, |
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25 { 640, 6 }, |
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26 { 768, 5 }, |
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27 { 896, 4 }, |
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28 { 1024, 4 }, |
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29 { 1152, 3 }, |
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30 { 1280, 3 }, |
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31 { 1408, 3 }, |
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32 { 1536, 3 }, |
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33 { 1664, 3 }, |
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34 { 1792, 2 } }; |
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35 |
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36 /* returns # of RM trials required for a given bit size */ |
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37 int mp_prime_rabin_miller_trials(int size) |
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38 { |
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39 int x; |
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40 |
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41 for (x = 0; x < (int)(sizeof(sizes)/(sizeof(sizes[0]))); x++) { |
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42 if (sizes[x].k == size) { |
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43 return sizes[x].t; |
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44 } else if (sizes[x].k > size) { |
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45 return (x == 0) ? sizes[0].t : sizes[x - 1].t; |
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46 } |
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47 } |
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48 return 1; |
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49 } |
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50 |
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51 |
