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 #include <libecc/fp/fp.h> 17 #include <libecc/fp/fp_add.h> 18 #include <libecc/fp/fp_mul.h> 19 #include <libecc/fp/fp_mul_redc1.h> 20 #include <libecc/fp/fp_montgomery.h> 21 22 /* Compute out = in1 + in2 mod p in the Montgomery form. 23 * Inputs and outputs are in their Montgomery form. 24 * Returns 0 on success, -1 on error. 25 * 26 * Aliasing is supported. 27 */ 28 int fp_add_monty(fp_t out, fp_src_t in1, fp_src_t in2) 29 { 30 return fp_add(out, in1, in2); 31 } 32 33 /* Compute out = in1 - in2 mod p in the Montgomery form. 34 * Inputs and outputs are in their Montgomery form. 35 * Returns 0 on success, -1 on error. 36 * 37 * Aliasing is supported. 38 */ 39 int fp_sub_monty(fp_t out, fp_src_t in1, fp_src_t in2) 40 { 41 return fp_sub(out, in1, in2); 42 } 43 44 /* Compute out = in1 * in2 mod p in the Montgomery form. 45 * Inputs and outputs are in their Montgomery form. 46 * Returns 0 on success, -1 on error. 47 * 48 * Aliasing is supported. 49 */ 50 int fp_mul_monty(fp_t out, fp_src_t in1, fp_src_t in2) 51 { 52 return fp_mul_redc1(out, in1, in2); 53 } 54 55 /* Compute out = in * in mod p in the Montgomery form. 56 * Inputs and outputs are in their Montgomery form. 57 * Returns 0 on success, -1 on error. 58 * 59 * Aliasing is supported. 60 */ 61 int fp_sqr_monty(fp_t out, fp_src_t in) 62 { 63 return fp_sqr_redc1(out, in); 64 } 65 66 /* 67 * Compute out such that in1 = out * in2 mod p in the Montgomery form. 68 * Inputs and outputs are in their Montgomery form. 69 * Returns 0 on success, -1 on error. out must be initialized by the caller. 70 * 71 * Aliasing is supported. 72 */ 73 int fp_div_monty(fp_t out, fp_src_t in1, fp_src_t in2) 74 { 75 int ret, iszero; 76 77 ret = fp_check_initialized(in1); EG(ret, err); 78 ret = fp_check_initialized(in2); EG(ret, err); 79 ret = fp_check_initialized(out); EG(ret, err); 80 81 MUST_HAVE((out->ctx == in1->ctx), ret, err); 82 MUST_HAVE((out->ctx == in2->ctx), ret, err); 83 FORCE_USED_VAR(iszero); /* silence warning when macro results in nothing */ 84 MUST_HAVE(!fp_iszero(in2, &iszero) && (!iszero), ret, err); 85 86 ret = fp_div(out, in1, in2); EG(ret, err); 87 ret = fp_redcify(out, out); 88 89 err: 90 return ret; 91 } 92