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1 #include <tommath.h> |
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2 #ifdef BN_MP_INVMOD_C |
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3 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
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4 * |
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5 * LibTomMath is a library that provides multiple-precision |
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6 * integer arithmetic as well as number theoretic functionality. |
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7 * |
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8 * The library was designed directly after the MPI library by |
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9 * Michael Fromberger but has been written from scratch with |
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10 * additional optimizations in place. |
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11 * |
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12 * The library is free for all purposes without any express |
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13 * guarantee it works. |
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14 * |
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15 * Tom St Denis, [email protected], http://math.libtomcrypt.com |
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16 */ |
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17 |
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18 /* hac 14.61, pp608 */ |
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19 int mp_invmod (mp_int * a, mp_int * b, mp_int * c) |
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20 { |
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21 /* b cannot be negative */ |
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22 if (b->sign == MP_NEG || mp_iszero(b) == 1) { |
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23 return MP_VAL; |
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24 } |
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25 |
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26 #ifdef BN_FAST_MP_INVMOD_C |
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27 /* if the modulus is odd we can use a faster routine instead */ |
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28 if (mp_isodd (b) == 1) { |
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29 return fast_mp_invmod (a, b, c); |
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30 } |
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31 #endif |
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32 |
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33 #ifdef BN_MP_INVMOD_SLOW_C |
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34 return mp_invmod_slow(a, b, c); |
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35 #endif |
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36 |
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37 return MP_VAL; |
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38 } |
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39 #endif |
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40 |
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41 /* $Source: /cvs/libtom/libtommath/bn_mp_invmod.c,v $ */ |
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42 /* $Revision: 1.3 $ */ |
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43 /* $Date: 2006/03/31 14:18:44 $ */ |
