5 * Elliptic Curve Arithmetic Functions
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7 * Copyright (C) Lenka Fibikova 2000
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18 #include "bn_modfs.h"
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26 ret=(EC *)malloc(sizeof(EC));
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27 if (ret == NULL) return NULL;
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32 ret->is_in_mont = 0;
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34 if (ret->A == NULL || ret->B == NULL || ret->p == NULL || ret->h == NULL)
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36 if (ret->A != NULL) BN_free(ret->A);
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37 if (ret->B != NULL) BN_free(ret->B);
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38 if (ret->p != NULL) BN_free(ret->p);
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39 if (ret->h != NULL) BN_free(ret->h);
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47 void EC_clear_free(EC *E)
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49 if (E == NULL) return;
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51 if (E->A != NULL) BN_clear_free(E->A);
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52 if (E->B != NULL) BN_clear_free(E->B);
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53 if (E->p != NULL) BN_clear_free(E->p);
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54 if (E->h != NULL) BN_clear_free(E->h);
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61 int EC_to_montgomery(EC *E, BN_MONTGOMERY *mont, BN_CTX *ctx)
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64 assert(E->A != NULL && E->B != NULL && E->p != NULL && E->h != NULL);
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66 assert(mont != NULL);
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67 assert(mont->p != NULL);
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69 assert(ctx != NULL);
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71 if (E->is_in_mont) return 1;
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73 if (!BN_lshift(E->A, E->A, mont->R_num_bits)) return 0;
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74 if (!BN_mod(E->A, E->A, mont->p, ctx)) return 0;
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76 if (!BN_lshift(E->B, E->B, mont->R_num_bits)) return 0;
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77 if (!BN_mod(E->B, E->B, mont->p, ctx)) return 0;
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79 if (!BN_lshift(E->h, E->h, mont->R_num_bits)) return 0;
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80 if (!BN_mod(E->h, E->h, mont->p, ctx)) return 0;
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88 int EC_from_montgomery(EC *E, BN_MONTGOMERY *mont, BN_CTX *ctx)
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91 assert(E->A != NULL && E->B != NULL && E->p != NULL && E->h != NULL);
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93 assert(mont != NULL);
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94 assert(mont->p != NULL);
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96 assert(ctx != NULL);
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98 if (!E->is_in_mont) return 1;
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100 if (!BN_mont_red(E->A, mont, ctx)) return 0;
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101 if (!BN_mont_red(E->B, mont, ctx)) return 0;
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102 if (!BN_mont_red(E->h, mont, ctx)) return 0;
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107 #endif /* MONTGOMERY */
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109 int EC_set_half(EC *E)
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110 /* h <- 1/2 mod p = (p + 1)/2 */
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113 assert(E->p != NULL);
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114 assert(E->h != NULL);
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115 assert(!E->is_in_mont);
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117 if (BN_copy(E->h, E->p) == NULL) return 0;
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118 if (!BN_add_word(E->h, 1)) return 0;
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119 if (!BN_rshift1(E->h, E->h)) return 0;
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