42 lines
1.0 KiB
C
42 lines
1.0 KiB
C
#include <tommath_private.h>
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#ifdef BN_MP_DR_IS_MODULUS_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis
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*
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* LibTomMath is a library that provides multiple-precision
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* integer arithmetic as well as number theoretic functionality.
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*
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* The library was designed directly after the MPI library by
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* Michael Fromberger but has been written from scratch with
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* additional optimizations in place.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*/
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/* determines if a number is a valid DR modulus */
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int mp_dr_is_modulus(const mp_int *a)
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{
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int ix;
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/* must be at least two digits */
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if (a->used < 2) {
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return 0;
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}
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/* must be of the form b**k - a [a <= b] so all
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* but the first digit must be equal to -1 (mod b).
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*/
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for (ix = 1; ix < a->used; ix++) {
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if (a->dp[ix] != MP_MASK) {
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return 0;
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}
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}
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return 1;
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}
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#endif
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/* ref: $Format:%D$ */
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/* git commit: $Format:%H$ */
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/* commit time: $Format:%ai$ */
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