25 lines
873 B
C
25 lines
873 B
C
#include "amplify_tommath_private.h"
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#ifdef AMPLIFY_BN_MP_INVMOD_C
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/* LibTomMath, multiple-precision integer library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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/* Modifications Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. */
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/* hac 14.61, pp608 */
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amplify_mp_err amplify_mp_invmod(const amplify_mp_int *a, const amplify_mp_int *b, amplify_mp_int *c)
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{
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/* b cannot be negative and has to be >1 */
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if ((b->sign == AMPLIFY_MP_NEG) || (amplify_mp_cmp_d(b, 1uL) != AMPLIFY_MP_GT)) {
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return AMPLIFY_MP_VAL;
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}
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/* if the modulus is odd we can use a faster routine instead */
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if (AMPLIFY_MP_HAS(S_MP_INVMOD_FAST) && AMPLIFY_MP_IS_ODD(b)) {
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return amplify_s_mp_invmod_fast(a, b, c);
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}
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return AMPLIFY_MP_HAS(S_MP_INVMOD_SLOW)
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? amplify_s_mp_invmod_slow(a, b, c)
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: AMPLIFY_MP_VAL;
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}
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#endif
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