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freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/crypto/libecc/src/fp/fp_montgomery.c
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/*

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 *  Copyright (C) 2017 - This file is part of libecc project

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 *

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 *  Authors:

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 *      Ryad BENADJILA <[email protected]>

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 *      Arnaud EBALARD <[email protected]>

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 *      Jean-Pierre FLORI <[email protected]>

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 *

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 *  Contributors:

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 *      Nicolas VIVET <[email protected]>

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 *      Karim KHALFALLAH <[email protected]>

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 *

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 *  This software is licensed under a dual BSD and GPL v2 license.

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 *  See LICENSE file at the root folder of the project.

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 */

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#include <libecc/fp/fp.h>

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#include <libecc/fp/fp_add.h>

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#include <libecc/fp/fp_mul.h>

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#include <libecc/fp/fp_mul_redc1.h>

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#include <libecc/fp/fp_montgomery.h>

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/* Compute out = in1 + in2 mod p in the Montgomery form.

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 * Inputs and outputs are in their Montgomery form.

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 * Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_add_monty(fp_t out, fp_src_t in1, fp_src_t in2)

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{

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	return fp_add(out, in1, in2);

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}

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/* Compute out = in1 - in2 mod p in the Montgomery form.

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 * Inputs and outputs are in their Montgomery form.

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 * Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_sub_monty(fp_t out, fp_src_t in1, fp_src_t in2)

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{

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	return fp_sub(out, in1, in2);

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}

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/* Compute out = in1 * in2 mod p in the Montgomery form.

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 * Inputs and outputs are in their Montgomery form.

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 * Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_mul_monty(fp_t out, fp_src_t in1, fp_src_t in2)

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{

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	return fp_mul_redc1(out, in1, in2);

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}

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/* Compute out = in * in mod p in the Montgomery form.

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 * Inputs and outputs are in their Montgomery form.

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 * Returns 0 on success, -1 on error.

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 *

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 * Aliasing is supported.

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 */

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int fp_sqr_monty(fp_t out, fp_src_t in)

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{

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	return fp_sqr_redc1(out, in);

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}

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/*

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 * Compute out such that in1 = out * in2 mod p in the Montgomery form.

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 * Inputs and outputs are in their Montgomery form.

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 * Returns 0 on success, -1 on error. out must be initialized by the caller.

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 *

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 * Aliasing is supported.

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 */

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int fp_div_monty(fp_t out, fp_src_t in1, fp_src_t in2)

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{

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	int ret, iszero;

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	ret = fp_check_initialized(in1); EG(ret, err);

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	ret = fp_check_initialized(in2); EG(ret, err);

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	ret = fp_check_initialized(out); EG(ret, err);

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	MUST_HAVE((out->ctx == in1->ctx), ret, err);

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	MUST_HAVE((out->ctx == in2->ctx), ret, err);

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        FORCE_USED_VAR(iszero); /* silence warning when macro results in nothing */

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	MUST_HAVE(!fp_iszero(in2, &iszero) && (!iszero), ret, err);

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	ret = fp_div(out, in1, in2); EG(ret, err);

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	ret = fp_redcify(out, out);

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err:

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	return ret;

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}

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