1  /*
 2   *  Copyright (C) 2017 - This file is part of libecc project
 3   *
 4   *  Authors:
 5   *      Ryad BENADJILA <ryadbenadjila@gmail.com>
 6   *      Arnaud EBALARD <arnaud.ebalard@ssi.gouv.fr>
 7   *      Jean-Pierre FLORI <jean-pierre.flori@ssi.gouv.fr>
 8   *
 9   *  Contributors:
10   *      Nicolas VIVET <nicolas.vivet@ssi.gouv.fr>
11   *      Karim KHALFALLAH <karim.khalfallah@ssi.gouv.fr>
12   *
13   *  This software is licensed under a dual BSD and GPL v2 license.
14   *  See LICENSE file at the root folder of the project.
15   */
16  #ifndef __FP_H__
17  #define __FP_H__
18  
19  #include <libecc/nn/nn.h>
20  #include <libecc/nn/nn_div_public.h>
21  #include <libecc/nn/nn_modinv.h>
22  #include <libecc/nn/nn_mul_public.h>
23  #include <libecc/nn/nn_mul_redc1.h>
24  #include <libecc/fp/fp_config.h>
25  
26  /*
27   * First, definition of our Fp context, containing all the elements
28   * needed to efficiently implement Fp operations.
29   */
30  
31  typedef struct {
32  	/*
33  	 * Value of p (extended by one word to handle
34  	 * overflows in Fp). p_bitlen provides its
35  	 * length in bit.
36  	 */
37  	nn p;
38  	bitcnt_t p_bitlen;
39  
40  	/* -p^-1 mod 2^(bitsizeof(word_t)) */
41  	word_t mpinv;
42  
43  	/* 2^bitsizeof(p) mod p */
44  	nn r;
45  
46  	/* 2^(2*bitsizeof(p)) mod p */
47  	nn r_square;
48  
49  	/* clz(p) */
50  	bitcnt_t p_shift;
51  	/* p << p_shift */
52  	nn p_normalized;
53  	/* floor(B^3/(DMSW(p_normalized) + 1)) - B */
54  	word_t p_reciprocal;
55  
56  	word_t magic;
57  } fp_ctx;
58  
59  typedef fp_ctx *fp_ctx_t;
60  typedef const fp_ctx *fp_ctx_src_t;
61  
62  ATTRIBUTE_WARN_UNUSED_RET int fp_ctx_check_initialized(fp_ctx_src_t ctx);
63  ATTRIBUTE_WARN_UNUSED_RET int fp_ctx_init(fp_ctx_t ctx, nn_src_t p, bitcnt_t p_bitlen,
64  		nn_src_t r, nn_src_t r_square,
65  		word_t mpinv,
66  		bitcnt_t p_shift, nn_src_t p_normalized, word_t p_reciprocal);
67  ATTRIBUTE_WARN_UNUSED_RET int fp_ctx_init_from_p(fp_ctx_t ctx, nn_src_t p);
68  
69  /*
70   * Then the definition of our Fp elements
71   */
72  
73  typedef struct {
74  	nn fp_val;
75  	fp_ctx_src_t ctx;
76  	word_t magic;
77  } fp;
78  
79  typedef fp *fp_t;
80  typedef const fp *fp_src_t;
81  
82  ATTRIBUTE_WARN_UNUSED_RET int fp_check_initialized(fp_src_t in);
83  ATTRIBUTE_WARN_UNUSED_RET int fp_init(fp_t A, fp_ctx_src_t fpctx);
84  ATTRIBUTE_WARN_UNUSED_RET int fp_init_from_buf(fp_t A, fp_ctx_src_t fpctx, const u8 *buf, u16 buflen);
85  void fp_uninit(fp_t A);
86  ATTRIBUTE_WARN_UNUSED_RET int fp_set_nn(fp_t out, nn_src_t in);
87  ATTRIBUTE_WARN_UNUSED_RET int fp_zero(fp_t out);
88  ATTRIBUTE_WARN_UNUSED_RET int fp_one(fp_t out);
89  ATTRIBUTE_WARN_UNUSED_RET int fp_set_word_value(fp_t out, word_t val);
90  ATTRIBUTE_WARN_UNUSED_RET int fp_cmp(fp_src_t in1, fp_src_t in2, int *cmp);
91  ATTRIBUTE_WARN_UNUSED_RET int fp_iszero(fp_src_t in, int *iszero);
92  ATTRIBUTE_WARN_UNUSED_RET int fp_copy(fp_t out, fp_src_t in);
93  ATTRIBUTE_WARN_UNUSED_RET int fp_tabselect(fp_t out, u8 idx, fp_src_t *tab, u8 tabsize);
94  ATTRIBUTE_WARN_UNUSED_RET int fp_eq_or_opp(fp_src_t in1, fp_src_t in2, int *eq_or_opp);
95  ATTRIBUTE_WARN_UNUSED_RET int fp_import_from_buf(fp_t out_fp, const u8 *buf, u16 buflen);
96  ATTRIBUTE_WARN_UNUSED_RET int fp_export_to_buf(u8 *buf, u16 buflen, fp_src_t in_fp);
97  
98  #endif /* __FP_H__ */