d3eed33709
The external representation before included more than just endianness (like reading in Mongtomery curve scalars or converting hashes to numbers in a standard compliant way). These are higher level concepts and are out of scope for Bignum and for the modulus structure. Passing endianness as a parameter is a step towards removing it from the modulus structure. Signed-off-by: Janos Follath <janos.follath@arm.com>
250 lines
9.7 KiB
C
250 lines
9.7 KiB
C
/**
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* Low-level modular bignum functions
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*
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* This interface should only be used by the higher-level modular bignum
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* module (bignum_mod.c) and the ECP module (ecp.c, ecp_curves.c). All other
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* modules should use the high-level modular bignum interface (bignum_mod.h)
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* or the legacy bignum interface (bignum.h).
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*
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* This is a low-level interface to operations on integers modulo which
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* has no protection against passing invalid arguments such as arrays of
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* the wrong size. The functions in bignum_mod.h provide a higher-level
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* interface that includes protections against accidental misuse, at the
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* expense of code size and sometimes more cumbersome memory management.
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*/
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/*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef MBEDTLS_BIGNUM_MOD_RAW_H
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#define MBEDTLS_BIGNUM_MOD_RAW_H
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#include "common.h"
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#if defined(MBEDTLS_BIGNUM_C)
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#include "mbedtls/bignum.h"
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#endif
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#include "bignum_mod.h"
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/**
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* \brief Perform a safe conditional copy of an MPI which doesn't reveal
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* whether the assignment was done or not.
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*
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* The size to copy is determined by \p N.
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*
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* \param[out] X The address of the destination MPI.
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* This must be initialized. Must have enough limbs to
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* store the full value of \p A.
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* \param[in] A The address of the source MPI. This must be initialized.
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* \param[in] N The address of the modulus related to \p X and \p A.
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* \param assign The condition deciding whether to perform the
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* assignment or not. Must be either 0 or 1:
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* * \c 1: Perform the assignment `X = A`.
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* * \c 0: Keep the original value of \p X.
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*
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* \note This function avoids leaking any information about whether
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* the assignment was done or not.
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*
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* \warning If \p assign is neither 0 nor 1, the result of this function
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* is indeterminate, and the resulting value in \p X might be
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* neither its original value nor the value in \p A.
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*/
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void mbedtls_mpi_mod_raw_cond_assign( mbedtls_mpi_uint *X,
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const mbedtls_mpi_uint *A,
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const mbedtls_mpi_mod_modulus *N,
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unsigned char assign );
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/**
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* \brief Perform a safe conditional swap of two MPIs which doesn't reveal
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* whether the swap was done or not.
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*
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* The size to swap is determined by \p N.
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*
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* \param[in,out] X The address of the first MPI. This must be initialized.
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* \param[in,out] Y The address of the second MPI. This must be initialized.
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* \param[in] N The address of the modulus related to \p X and \p Y.
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* \param swap The condition deciding whether to perform
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* the swap or not. Must be either 0 or 1:
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* * \c 1: Swap the values of \p X and \p Y.
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* * \c 0: Keep the original values of \p X and \p Y.
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*
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* \note This function avoids leaking any information about whether
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* the swap was done or not.
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*
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* \warning If \p swap is neither 0 nor 1, the result of this function
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* is indeterminate, and both \p X and \p Y might end up with
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* values different to either of the original ones.
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*/
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void mbedtls_mpi_mod_raw_cond_swap( mbedtls_mpi_uint *X,
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mbedtls_mpi_uint *Y,
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const mbedtls_mpi_mod_modulus *N,
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unsigned char swap );
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/** Import X from unsigned binary data.
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*
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* The MPI needs to have enough limbs to store the full value (including any
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* most significant zero bytes in the input).
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*
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* \param[out] X The address of the MPI. The size is determined by \p m.
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* (In particular, it must have at least as many limbs as
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* the modulus \p m.)
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* \param[in] m The address of the modulus related to \p X.
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* \param[in] input The input buffer to import from.
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* \param input_length The length in bytes of \p input.
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* \param ext_rep The endianness of the number in the input buffer.
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*
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* \return \c 0 if successful.
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* \return #MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if \p X isn't
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* large enough to hold the value in \p input.
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* \return #MBEDTLS_ERR_MPI_BAD_INPUT_DATA if the external representation
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* of \p m is invalid or \p X is not less than \p m.
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*/
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int mbedtls_mpi_mod_raw_read( mbedtls_mpi_uint *X,
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const mbedtls_mpi_mod_modulus *m,
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const unsigned char *input,
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size_t input_length,
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mbedtls_mpi_mod_ext_rep ext_rep );
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/** Export A into unsigned binary data.
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*
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* \param[in] A The address of the MPI. The size is determined by \p m.
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* (In particular, it must have at least as many limbs as
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* the modulus \p m.)
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* \param[in] m The address of the modulus related to \p A.
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* \param[out] output The output buffer to export to.
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* \param output_length The length in bytes of \p output.
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* \param ext_rep The endianness in which the number should be written into the output buffer.
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*
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* \return \c 0 if successful.
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* \return #MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if \p output isn't
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* large enough to hold the value of \p A.
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* \return #MBEDTLS_ERR_MPI_BAD_INPUT_DATA if the external representation
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* of \p m is invalid.
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*/
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int mbedtls_mpi_mod_raw_write( const mbedtls_mpi_uint *A,
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const mbedtls_mpi_mod_modulus *m,
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unsigned char *output,
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size_t output_length,
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mbedtls_mpi_mod_ext_rep ext_rep );
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/* BEGIN MERGE SLOT 1 */
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/* END MERGE SLOT 1 */
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/* BEGIN MERGE SLOT 2 */
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/** \brief Subtract two MPIs, returning the residue modulo the specified
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* modulus.
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*
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* The size of the operation is determined by \p N. \p A and \p B must have
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* the same number of limbs as \p N.
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*
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* \p X may be aliased to \p A or \p B, or even both, but may not overlap
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* either otherwise.
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*
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* \param[out] X The address of the result MPI.
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* This must be initialized. Must have enough limbs to
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* store the full value of the result.
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* \param[in] A The address of the first MPI. This must be initialized.
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* \param[in] B The address of the second MPI. This must be initialized.
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* \param[in] N The address of the modulus. Used to perform a modulo
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* operation on the result of the subtraction.
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*/
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void mbedtls_mpi_mod_raw_sub( mbedtls_mpi_uint *X,
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const mbedtls_mpi_uint *A,
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const mbedtls_mpi_uint *B,
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const mbedtls_mpi_mod_modulus *N );
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/* END MERGE SLOT 2 */
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/* BEGIN MERGE SLOT 3 */
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/* END MERGE SLOT 3 */
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/* BEGIN MERGE SLOT 4 */
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/* END MERGE SLOT 4 */
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/* BEGIN MERGE SLOT 5 */
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/**
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* \brief Perform a known-size modular addition.
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*
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* Calculate `A + B modulo N`.
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*
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* The number of limbs in each operand, and the result, is given by the
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* modulus \p N.
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*
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* \p X may be aliased to \p A or \p B, or even both, but may not overlap
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* either otherwise.
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*
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* \param[out] X The result of the modular addition.
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* \param[in] A Little-endian presentation of the left operand. This
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* must be smaller than \p N.
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* \param[in] B Little-endian presentation of the right operand. This
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* must be smaller than \p N.
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* \param[in] N The address of the modulus.
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*/
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void mbedtls_mpi_mod_raw_add( mbedtls_mpi_uint *X,
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const mbedtls_mpi_uint *A,
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const mbedtls_mpi_uint *B,
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const mbedtls_mpi_mod_modulus *N );
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/* END MERGE SLOT 5 */
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/* BEGIN MERGE SLOT 6 */
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/* END MERGE SLOT 6 */
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/* BEGIN MERGE SLOT 7 */
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/** Convert an MPI into Montgomery form.
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*
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* \param X The address of the MPI.
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* Must have the same number of limbs as \p m.
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* \param m The address of the modulus, which gives the size of
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* the base `R` = 2^(biL*m->limbs).
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*
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* \return \c 0 if successful.
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*/
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int mbedtls_mpi_mod_raw_to_mont_rep( mbedtls_mpi_uint *X,
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const mbedtls_mpi_mod_modulus *m );
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/** Convert an MPI back from Montgomery representation.
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*
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* \param X The address of the MPI.
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* Must have the same number of limbs as \p m.
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* \param m The address of the modulus, which gives the size of
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* the base `R`= 2^(biL*m->limbs).
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*
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* \return \c 0 if successful.
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*/
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int mbedtls_mpi_mod_raw_from_mont_rep( mbedtls_mpi_uint *X,
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const mbedtls_mpi_mod_modulus *m );
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/* END MERGE SLOT 7 */
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/* BEGIN MERGE SLOT 8 */
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/* END MERGE SLOT 8 */
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/* BEGIN MERGE SLOT 9 */
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/* END MERGE SLOT 9 */
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/* BEGIN MERGE SLOT 10 */
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/* END MERGE SLOT 10 */
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#endif /* MBEDTLS_BIGNUM_MOD_RAW_H */
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