mbedtls/tests/suites/test_suite_bignum_mod_raw.function

/* BEGIN_HEADER */
#include "mbedtls/bignum.h"
#include "mbedtls/entropy.h"
#include "bignum_core.h"
#include "bignum_mod_raw.h"
#include "constant_time_internal.h"
#include "test/constant_flow.h"

/* END_HEADER */

/* BEGIN_DEPENDENCIES
 * depends_on:MBEDTLS_BIGNUM_C
 * END_DEPENDENCIES
 */

/* BEGIN_CASE */
void mpi_mod_raw_io( data_t *input, int nb_int, int nx_32_int,
                     int iendian, int iret, int oret )
{
    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    if( iret != 0 )
        TEST_ASSERT( oret == 0 );

    TEST_LE_S( 0, nb_int );
    size_t nb = nb_int;

    unsigned char buf[1024];
    TEST_LE_U( nb, sizeof( buf ) );

    /* nx_32_int is the number of 32 bit limbs, if we have 64 bit limbs we need
     * to halve the number of limbs to have the same size. */
    size_t nx;
    TEST_LE_S( 0, nx_32_int );
    if( sizeof( mbedtls_mpi_uint ) == 8 )
        nx = nx_32_int / 2 + nx_32_int % 2;
    else
        nx = nx_32_int;

    mbedtls_mpi_uint X[sizeof( buf ) / sizeof( mbedtls_mpi_uint )];
    TEST_LE_U( nx, sizeof( X ) / sizeof( X[0] ) );

    int endian;
    if( iendian == MBEDTLS_MPI_MOD_EXT_REP_INVALID )
        endian = MBEDTLS_MPI_MOD_EXT_REP_LE;
    else
        endian = iendian;

    mbedtls_mpi_uint init[sizeof( X ) / sizeof( X[0] )];
    memset( init, 0xFF, sizeof( init ) );
    int ret = mbedtls_mpi_mod_modulus_setup( &m, init, nx,
                                             MBEDTLS_MPI_MOD_REP_MONTGOMERY );
    TEST_EQUAL( ret, 0 );

    if( iendian == MBEDTLS_MPI_MOD_EXT_REP_INVALID && iret != 0 )
       endian = MBEDTLS_MPI_MOD_EXT_REP_INVALID;

    ret = mbedtls_mpi_mod_raw_read( X, &m, input->x, input->len, endian );
    TEST_EQUAL( ret, iret );

    if( iret == 0 )
    {
        if( iendian == MBEDTLS_MPI_MOD_EXT_REP_INVALID && oret != 0 )
            endian = MBEDTLS_MPI_MOD_EXT_REP_INVALID;

        ret = mbedtls_mpi_mod_raw_write( X, &m, buf, nb, endian );
        TEST_EQUAL( ret, oret );
    }

    if( ( iret == 0 ) && ( oret == 0 ) )
    {
        if( nb > input->len )
        {
            if( endian == MBEDTLS_MPI_MOD_EXT_REP_BE )
            {
                size_t leading_zeroes = nb - input->len;
                TEST_ASSERT( memcmp( buf + nb - input->len, input->x, input->len ) == 0 );
                for( size_t i = 0; i < leading_zeroes; i++ )
                    TEST_EQUAL( buf[i], 0 );
            }
            else
            {
                TEST_ASSERT( memcmp( buf, input->x, input->len ) == 0 );
                for( size_t i = input->len; i < nb; i++ )
                    TEST_EQUAL( buf[i], 0 );
            }
        }
        else
        {
            if( endian == MBEDTLS_MPI_MOD_EXT_REP_BE )
            {
                size_t leading_zeroes = input->len - nb;
                TEST_ASSERT( memcmp( input->x + input->len - nb, buf, nb ) == 0 );
                for( size_t i = 0; i < leading_zeroes; i++ )
                    TEST_EQUAL( input->x[i], 0 );
            }
            else
            {
                TEST_ASSERT( memcmp( input->x, buf, nb ) == 0 );
                for( size_t i = nb; i < input->len; i++ )
                    TEST_EQUAL( input->x[i], 0 );
            }
        }
    }

exit:
    mbedtls_mpi_mod_modulus_free( &m );
}
/* END_CASE */

/* BEGIN_CASE */
void mpi_mod_raw_cond_assign( char * input_X,
                              char * input_Y,
                              int input_bytes )
{
    mbedtls_mpi_uint *X = NULL;
    mbedtls_mpi_uint *Y = NULL;
    mbedtls_mpi_uint *buff_m = NULL;
    size_t limbs_X;
    size_t limbs_Y;

    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    TEST_EQUAL( mbedtls_test_read_mpi_core( &X, &limbs_X, input_X ), 0 );
    TEST_EQUAL( mbedtls_test_read_mpi_core( &Y, &limbs_Y, input_Y ), 0 );

    size_t limbs = limbs_X;
    size_t copy_limbs = CHARS_TO_LIMBS( input_bytes );
    size_t bytes = limbs * sizeof( mbedtls_mpi_uint );
    size_t copy_bytes = copy_limbs * sizeof( mbedtls_mpi_uint );

    TEST_EQUAL( limbs_X, limbs_Y );
    TEST_ASSERT( copy_limbs <= limbs );

    ASSERT_ALLOC( buff_m, copy_limbs );
    memset( buff_m, 0xFF, copy_limbs );
    TEST_EQUAL( mbedtls_mpi_mod_modulus_setup(
                        &m, buff_m, copy_limbs,
                        MBEDTLS_MPI_MOD_REP_MONTGOMERY ), 0 );

    /* condition is false */
    TEST_CF_SECRET( X, bytes );
    TEST_CF_SECRET( Y, bytes );

    mbedtls_mpi_mod_raw_cond_assign( X, Y, &m, 0 );

    TEST_CF_PUBLIC( X, bytes );
    TEST_CF_PUBLIC( Y, bytes );

    TEST_ASSERT( memcmp( X, Y, bytes ) != 0 );

    /* condition is true */
    TEST_CF_SECRET( X, bytes );
    TEST_CF_SECRET( Y, bytes );

    mbedtls_mpi_mod_raw_cond_assign( X, Y, &m, 1 );

    TEST_CF_PUBLIC( X, bytes );
    TEST_CF_PUBLIC( Y, bytes );

    /* Check if the given length is copied even it is smaller
       than the length of the given MPIs. */
    if( copy_limbs <limbs )
    {
        ASSERT_COMPARE( X, copy_bytes, Y, copy_bytes );
        TEST_ASSERT( memcmp( X, Y, bytes ) != 0 );
    }
    else
        ASSERT_COMPARE( X, bytes, Y, bytes );

exit:
    mbedtls_free( X );
    mbedtls_free( Y );

    mbedtls_mpi_mod_modulus_free( &m );
    mbedtls_free( buff_m );
}
/* END_CASE */

/* BEGIN_CASE */
void mpi_mod_raw_cond_swap( char * input_X,
                            char * input_Y,
                            int input_bytes )
{
    mbedtls_mpi_uint *tmp_X = NULL;
    mbedtls_mpi_uint *tmp_Y = NULL;
    mbedtls_mpi_uint *X = NULL;
    mbedtls_mpi_uint *Y = NULL;
    mbedtls_mpi_uint *buff_m = NULL;
    size_t limbs_X;
    size_t limbs_Y;

    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    TEST_EQUAL( mbedtls_test_read_mpi_core( &tmp_X, &limbs_X, input_X ), 0 );
    TEST_EQUAL( mbedtls_test_read_mpi_core( &tmp_Y, &limbs_Y, input_Y ), 0 );

    size_t limbs = limbs_X;
    size_t copy_limbs = CHARS_TO_LIMBS( input_bytes );
    size_t bytes = limbs * sizeof( mbedtls_mpi_uint );
    size_t copy_bytes = copy_limbs * sizeof( mbedtls_mpi_uint );

    TEST_EQUAL( limbs_X, limbs_Y );
    TEST_ASSERT( copy_limbs <= limbs );

    ASSERT_ALLOC( buff_m, copy_limbs );
    memset( buff_m, 0xFF, copy_limbs );
    TEST_EQUAL( mbedtls_mpi_mod_modulus_setup(
                        &m, buff_m, copy_limbs,
                        MBEDTLS_MPI_MOD_REP_MONTGOMERY ), 0 );

    ASSERT_ALLOC( X, limbs );
    memcpy( X, tmp_X, bytes );

    ASSERT_ALLOC( Y, bytes );
    memcpy( Y, tmp_Y, bytes );

    /* condition is false */
    TEST_CF_SECRET( X, bytes );
    TEST_CF_SECRET( Y, bytes );

    mbedtls_mpi_mod_raw_cond_swap( X, Y, &m, 0 );

    TEST_CF_PUBLIC( X, bytes );
    TEST_CF_PUBLIC( Y, bytes );

    ASSERT_COMPARE( X, bytes, tmp_X, bytes );
    ASSERT_COMPARE( Y, bytes, tmp_Y, bytes );

    /* condition is true */
    TEST_CF_SECRET( X, bytes );
    TEST_CF_SECRET( Y, bytes );

    mbedtls_mpi_mod_raw_cond_swap( X, Y, &m, 1 );

    TEST_CF_PUBLIC( X, bytes );
    TEST_CF_PUBLIC( Y, bytes );

    /* Check if the given length is copied even it is smaller
       than the length of the given MPIs. */
    if( copy_limbs < limbs )
    {
        ASSERT_COMPARE( X, copy_bytes, tmp_Y, copy_bytes );
        ASSERT_COMPARE( Y, copy_bytes, tmp_X, copy_bytes );
        TEST_ASSERT( memcmp( X, tmp_X, bytes ) != 0 );
        TEST_ASSERT( memcmp( X, tmp_Y, bytes ) != 0 );
        TEST_ASSERT( memcmp( Y, tmp_X, bytes ) != 0 );
        TEST_ASSERT( memcmp( Y, tmp_Y, bytes ) != 0 );
    }
    else
    {
        ASSERT_COMPARE( X, bytes, tmp_Y, bytes );
        ASSERT_COMPARE( Y, bytes, tmp_X, bytes );
    }

exit:
    mbedtls_free( tmp_X );
    mbedtls_free( tmp_Y );
    mbedtls_free( X );
    mbedtls_free( Y );

    mbedtls_mpi_mod_modulus_free( &m );
    mbedtls_free( buff_m );
}
/* END_CASE */

/* BEGIN MERGE SLOT 1 */

/* END MERGE SLOT 1 */

/* BEGIN MERGE SLOT 2 */

/* BEGIN_CASE */
void mpi_mod_raw_sub( char * input_A,
                      char * input_B,
                      char * input_N,
                      char * result )
{
    mbedtls_mpi_uint *A = NULL;
    mbedtls_mpi_uint *B = NULL;
    mbedtls_mpi_uint *N = NULL;
    mbedtls_mpi_uint *X = NULL;
    mbedtls_mpi_uint *res = NULL;
    size_t limbs_A;
    size_t limbs_B;
    size_t limbs_N;
    size_t limbs_res;

    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    TEST_EQUAL( mbedtls_test_read_mpi_core( &A,   &limbs_A,   input_A ), 0 );
    TEST_EQUAL( mbedtls_test_read_mpi_core( &B,   &limbs_B,   input_B ), 0 );
    TEST_EQUAL( mbedtls_test_read_mpi_core( &N,   &limbs_N,   input_N ), 0 );
    TEST_EQUAL( mbedtls_test_read_mpi_core( &res, &limbs_res, result  ), 0 );

    size_t limbs = limbs_N;
    size_t bytes = limbs * sizeof( mbedtls_mpi_uint );

    TEST_EQUAL( limbs_A,   limbs );
    TEST_EQUAL( limbs_B,   limbs );
    TEST_EQUAL( limbs_res, limbs );

    ASSERT_ALLOC( X, limbs );

    TEST_EQUAL( mbedtls_mpi_mod_modulus_setup(
                        &m, N, limbs,
                        MBEDTLS_MPI_MOD_REP_MONTGOMERY ), 0 );

    mbedtls_mpi_mod_raw_sub( X, A, B, &m );
    ASSERT_COMPARE( X, bytes, res, bytes );

    /* alias X to A */
    memcpy( X, A, bytes );
    mbedtls_mpi_mod_raw_sub( X, X, B, &m );
    ASSERT_COMPARE( X, bytes, res, bytes );

    /* alias X to B */
    memcpy( X, B, bytes );
    mbedtls_mpi_mod_raw_sub( X, A, X, &m );
    ASSERT_COMPARE( X, bytes, res, bytes );

    /* A == B: alias A and B */
    if( memcmp( A, B, bytes ) == 0 )
    {
        mbedtls_mpi_mod_raw_sub( X, A, A, &m );
        ASSERT_COMPARE( X, bytes, res, bytes );

        /* X, A, B all aliased together */
        memcpy( X, A, bytes );
        mbedtls_mpi_mod_raw_sub( X, X, X, &m );
        ASSERT_COMPARE( X, bytes, res, bytes );
    }
exit:
    mbedtls_free( A );
    mbedtls_free( B );
    mbedtls_free( X );
    mbedtls_free( res );

    mbedtls_mpi_mod_modulus_free( &m );
    mbedtls_free( N );
}
/* END_CASE */

/* BEGIN_CASE */
void mpi_mod_raw_mul( char * input_A,
                      char * input_B,
                      char * input_N,
                      char * result )
{
    mbedtls_mpi_uint *A = NULL;
    mbedtls_mpi_uint *B = NULL;
    mbedtls_mpi_uint *N = NULL;
    mbedtls_mpi_uint *X = NULL;
    mbedtls_mpi_uint *R = NULL;
    mbedtls_mpi_uint *T = NULL;
    size_t limbs_A;
    size_t limbs_B;
    size_t limbs_N;
    size_t limbs_R;

    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    TEST_EQUAL( mbedtls_test_read_mpi_core( &A, &limbs_A, input_A ), 0 );
    TEST_EQUAL( mbedtls_test_read_mpi_core( &B, &limbs_B, input_B ), 0 );
    TEST_EQUAL( mbedtls_test_read_mpi_core( &N, &limbs_N, input_N ), 0 );
    TEST_EQUAL( mbedtls_test_read_mpi_core( &R, &limbs_R, result  ), 0 );

    const size_t limbs = limbs_N;
    const size_t bytes = limbs * sizeof( mbedtls_mpi_uint );

    TEST_EQUAL( limbs_A, limbs );
    TEST_EQUAL( limbs_B, limbs );
    TEST_EQUAL( limbs_R, limbs );

    ASSERT_ALLOC( X, limbs );

    TEST_EQUAL( mbedtls_mpi_mod_modulus_setup(
                        &m, N, limbs,
                        MBEDTLS_MPI_MOD_REP_MONTGOMERY ), 0 );

    const size_t limbs_T = limbs * 2 + 1;
    ASSERT_ALLOC( T, limbs_T );

    /* Convert to Montgomery representation */
    TEST_EQUAL( mbedtls_mpi_mod_raw_to_mont_rep( A, &m ), 0 );
    TEST_EQUAL( mbedtls_mpi_mod_raw_to_mont_rep( B, &m ), 0 );

    mbedtls_mpi_mod_raw_mul( X, A, B, &m, T );
    TEST_EQUAL( mbedtls_mpi_mod_raw_from_mont_rep( X, &m ), 0 );
    ASSERT_COMPARE( X, bytes, R, bytes );

    /* alias X to A */
    memcpy( X, A, bytes );
    mbedtls_mpi_mod_raw_mul( X, X, B, &m, T );
    TEST_EQUAL( mbedtls_mpi_mod_raw_from_mont_rep( X, &m ), 0 );
    ASSERT_COMPARE( X, bytes, R, bytes );

    /* alias X to B */
    memcpy( X, B, bytes );
    mbedtls_mpi_mod_raw_mul( X, A, X, &m, T );
    TEST_EQUAL( mbedtls_mpi_mod_raw_from_mont_rep( X, &m ), 0 );
    ASSERT_COMPARE( X, bytes, R, bytes );

    /* A == B: alias A and B */
    if( memcmp( A, B, bytes ) == 0 )
    {
        mbedtls_mpi_mod_raw_mul( X, A, A, &m, T );
        TEST_EQUAL( mbedtls_mpi_mod_raw_from_mont_rep( X, &m ), 0 );
        ASSERT_COMPARE( X, bytes, R, bytes );

        /* X, A, B all aliased together */
        memcpy( X, A, bytes );
        mbedtls_mpi_mod_raw_mul( X, X, X, &m, T );
        TEST_EQUAL( mbedtls_mpi_mod_raw_from_mont_rep( X, &m ), 0 );
        ASSERT_COMPARE( X, bytes, R, bytes );
    }

    /* A != B: test B * A */
    else
    {
        mbedtls_mpi_mod_raw_mul( X, B, A, &m, T );
        TEST_EQUAL( mbedtls_mpi_mod_raw_from_mont_rep( X, &m ), 0 );
        ASSERT_COMPARE( X, bytes, R, bytes );

        /* B * A: alias X to A */
        memcpy( X, A, bytes );
        mbedtls_mpi_mod_raw_mul( X, B, X, &m, T );
        TEST_EQUAL( mbedtls_mpi_mod_raw_from_mont_rep( X, &m ), 0 );
        ASSERT_COMPARE( X, bytes, R, bytes );

        /* B + A: alias X to B */
        memcpy( X, B, bytes );
        mbedtls_mpi_mod_raw_mul( X, X, A, &m, T );
        TEST_EQUAL( mbedtls_mpi_mod_raw_from_mont_rep( X, &m ), 0 );
        ASSERT_COMPARE( X, bytes, R, bytes );
    }

exit:
    mbedtls_free( A );
    mbedtls_free( B );
    mbedtls_free( X );
    mbedtls_free( R );
    mbedtls_free( T );

    mbedtls_mpi_mod_modulus_free( &m );
    mbedtls_free( N );
}
/* END_CASE */

/* END MERGE SLOT 2 */

/* BEGIN MERGE SLOT 3 */

/* BEGIN_CASE */
void mpi_mod_raw_inv_prime( char * input_N, char * input_A, char * input_X )
{
    mbedtls_mpi_uint *A = NULL;
    mbedtls_mpi_uint *N = NULL;
    mbedtls_mpi_uint *X = NULL;
    size_t A_limbs, N_limbs, X_limbs;
    mbedtls_mpi_uint *Y = NULL;
    mbedtls_mpi_uint *T = NULL;
    const mbedtls_mpi_uint *R2 = NULL;

    /* Legacy MPIs for computing R2 */
    mbedtls_mpi N_mpi;  /* gets set up manually, aliasing N, so no need to free */
    mbedtls_mpi R2_mpi;
    mbedtls_mpi_init( &R2_mpi );

    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &A, &A_limbs, input_A ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &N, &N_limbs, input_N ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &X, &X_limbs, input_X ) );
    ASSERT_ALLOC( Y, N_limbs );

    TEST_EQUAL( A_limbs, N_limbs );
    TEST_EQUAL( X_limbs, N_limbs );

    N_mpi.s = 1;
    N_mpi.p = N;
    N_mpi.n = N_limbs;
    TEST_EQUAL( 0, mbedtls_mpi_core_get_mont_r2_unsafe( &R2_mpi, &N_mpi ) );
    TEST_EQUAL( 0, mbedtls_mpi_grow( &R2_mpi, N_limbs ) );
    R2 = R2_mpi.p;

    size_t working_limbs = mbedtls_mpi_mod_raw_inv_prime_working_limbs( N_limbs );

    /* No point exactly duplicating the code in mbedtls_mpi_mod_raw_inv_prime_working_limbs()
     * to see if the output is correct, but we can check that it's in a
     * reasonable range.  The current calculation works out as
     * `1 + N_limbs * (welem + 4)`, where welem is the number of elements in
     * the window (1 << 1 up to 1 << 6).
     */
    size_t min_expected_working_limbs = 1 + N_limbs * 5;
    size_t max_expected_working_limbs = 1 + N_limbs * 68;

    TEST_LE_U( min_expected_working_limbs, working_limbs );
    TEST_LE_U( working_limbs, max_expected_working_limbs );

    ASSERT_ALLOC( T, working_limbs );

    mbedtls_mpi_mod_raw_inv_prime( Y, A, N, N_limbs, R2, T );

    TEST_EQUAL( 0, memcmp( X, Y, N_limbs * sizeof( mbedtls_mpi_uint ) ) );

    /* Check when output aliased to input */

    mbedtls_mpi_mod_raw_inv_prime( A, A, N, N_limbs, R2, T );

    TEST_EQUAL( 0, memcmp( X, A, N_limbs * sizeof( mbedtls_mpi_uint ) ) );

exit:
    mbedtls_free( T );
    mbedtls_free( A );
    mbedtls_free( N );
    mbedtls_free( X );
    mbedtls_free( Y );
    mbedtls_mpi_free( &R2_mpi );
    // R2 doesn't need to be freed as it is only aliasing R2_mpi
    // N_mpi doesn't need to be freed as it is only aliasing N
}
/* END_CASE */

/* END MERGE SLOT 3 */

/* BEGIN MERGE SLOT 4 */

/* END MERGE SLOT 4 */

/* BEGIN MERGE SLOT 5 */

/* BEGIN_CASE */
void mpi_mod_raw_add( char * input_N,
                      char * input_A, char * input_B,
                      char * input_S )
{
    mbedtls_mpi_uint *A = NULL;
    mbedtls_mpi_uint *B = NULL;
    mbedtls_mpi_uint *S = NULL;
    mbedtls_mpi_uint *N = NULL;
    mbedtls_mpi_uint *X = NULL;
    size_t A_limbs, B_limbs, N_limbs, S_limbs;

    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &A, &A_limbs, input_A ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &B, &B_limbs, input_B ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &N, &N_limbs, input_N ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &S, &S_limbs, input_S ) );

    /* Modulus gives the number of limbs; all inputs must have the same. */
    size_t limbs = N_limbs;
    size_t bytes = limbs * sizeof( *A );

    TEST_EQUAL( A_limbs, limbs );
    TEST_EQUAL( B_limbs, limbs );
    TEST_EQUAL( S_limbs, limbs );

    ASSERT_ALLOC( X, limbs );

    TEST_EQUAL( mbedtls_mpi_mod_modulus_setup(
                        &m, N, limbs,
                        MBEDTLS_MPI_MOD_REP_MONTGOMERY
                ), 0 );

    /* A + B => Correct result */
    mbedtls_mpi_mod_raw_add( X, A, B, &m );
    ASSERT_COMPARE( X, bytes, S, bytes );

    /* A + B: alias X to A => Correct result */
    memcpy( X, A, bytes );
    mbedtls_mpi_mod_raw_add( X, X, B, &m );
    ASSERT_COMPARE( X, bytes, S, bytes );

    /* A + B: alias X to B => Correct result */
    memcpy( X, B, bytes );
    mbedtls_mpi_mod_raw_add( X, A, X, &m );
    ASSERT_COMPARE( X, bytes, S, bytes );

    if ( memcmp(A, B, bytes ) == 0 )
    {
        /* A == B: alias A and B */

        /* A + A => Correct result */
        mbedtls_mpi_mod_raw_add( X, A, A, &m );
        ASSERT_COMPARE( X, bytes, S, bytes );

        /* A + A: X, A, B all aliased together => Correct result */
        memcpy( X, A, bytes );
        mbedtls_mpi_mod_raw_add( X, X, X, &m );
        ASSERT_COMPARE( X, bytes, S, bytes );
    }
    else
    {
        /* A != B: test B + A */

        /* B + A => Correct result */
        mbedtls_mpi_mod_raw_add( X, B, A, &m );
        ASSERT_COMPARE( X, bytes, S, bytes );

        /* B + A: alias X to A => Correct result */
        memcpy( X, A, bytes );
        mbedtls_mpi_mod_raw_add( X, B, X, &m );
        ASSERT_COMPARE( X, bytes, S, bytes );

        /* B + A: alias X to B => Correct result */
        memcpy( X, B, bytes );
        mbedtls_mpi_mod_raw_add( X, X, A, &m );
        ASSERT_COMPARE( X, bytes, S, bytes );
    }

exit:
    mbedtls_mpi_mod_modulus_free( &m );

    mbedtls_free( A );
    mbedtls_free( B );
    mbedtls_free( S );
    mbedtls_free( N );
    mbedtls_free( X );
}
/* END_CASE */
/* END MERGE SLOT 5 */

/* BEGIN MERGE SLOT 6 */

/* END MERGE SLOT 6 */

/* BEGIN MERGE SLOT 7 */
/* BEGIN_CASE */
void mpi_mod_raw_to_mont_rep( char * input_N, char * input_A, char * input_X )
{
    mbedtls_mpi_uint *N = NULL;
    mbedtls_mpi_uint *A = NULL;
    mbedtls_mpi_uint *X = NULL;
    size_t n_limbs, a_limbs, x_limbs, x_bytes;

    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    /* Read inputs */
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &N, &n_limbs, input_N ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &A, &a_limbs, input_A ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &X, &x_limbs, input_X ) );
    x_bytes = x_limbs * sizeof(mbedtls_mpi_uint);

    /* Test that input does not require more limbs than modulo */
    TEST_LE_U(a_limbs, n_limbs);

    TEST_EQUAL( 0, mbedtls_mpi_mod_modulus_setup( &m, N, n_limbs,
                MBEDTLS_MPI_MOD_REP_MONTGOMERY ) );

    /* Convert from cannonical into Montgomery representation */
    TEST_EQUAL(0, mbedtls_mpi_mod_raw_to_mont_rep( A, &m ) );

    /* The result matches expected value */
    ASSERT_COMPARE( A, x_bytes, X, x_bytes );
exit:
    mbedtls_mpi_mod_modulus_free( &m );
    mbedtls_free( N );
    mbedtls_free( A );
    mbedtls_free( X );
}
/* END_CASE */

/* BEGIN_CASE */
void mpi_mod_raw_from_mont_rep( char * input_N, char * input_A, char * input_X )
{
    mbedtls_mpi_uint *N = NULL;
    mbedtls_mpi_uint *A = NULL;
    mbedtls_mpi_uint *X = NULL;
    size_t n_limbs, a_limbs, x_limbs, x_bytes;

    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    /* Read inputs */
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &N, &n_limbs, input_N ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &A, &a_limbs, input_A ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &X, &x_limbs, input_X ) );
    x_bytes = x_limbs * sizeof(mbedtls_mpi_uint);

    /* Test that input does not require more limbs than modulo */
    TEST_LE_U(a_limbs, n_limbs);

    TEST_EQUAL( 0, mbedtls_mpi_mod_modulus_setup( &m, N, n_limbs,
                MBEDTLS_MPI_MOD_REP_MONTGOMERY ) );

    /* Convert from Montgomery into cannonical representation */
    TEST_EQUAL(0, mbedtls_mpi_mod_raw_from_mont_rep( A, &m ) );

    /* The result matches expected value */
    ASSERT_COMPARE( A, x_bytes, X, x_bytes );
exit:
    mbedtls_mpi_mod_modulus_free( &m );
    mbedtls_free( N );
    mbedtls_free( A );
    mbedtls_free( X );
}
/* END_CASE */

/* BEGIN_CASE */
void mpi_mod_raw_neg( char * input_N, char * input_A, char * input_X )
{
    mbedtls_mpi_uint *N = NULL;
    mbedtls_mpi_uint *A = NULL;
    mbedtls_mpi_uint *X = NULL;
    mbedtls_mpi_uint *R = NULL;
    mbedtls_mpi_uint *Z = NULL;
    size_t n_limbs, a_limbs, x_limbs, bytes;

    mbedtls_mpi_mod_modulus m;
    mbedtls_mpi_mod_modulus_init( &m );

    /* Read inputs */
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &N, &n_limbs, input_N ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &A, &a_limbs, input_A ) );
    TEST_EQUAL( 0, mbedtls_test_read_mpi_core( &X, &x_limbs, input_X ) );

    TEST_EQUAL( a_limbs, n_limbs );
    TEST_EQUAL( x_limbs, n_limbs );
    bytes = n_limbs * sizeof( mbedtls_mpi_uint );

    ASSERT_ALLOC( R, n_limbs );
    ASSERT_ALLOC( Z, n_limbs );

    TEST_EQUAL( 0, mbedtls_mpi_mod_modulus_setup( &m, N, n_limbs,
            MBEDTLS_MPI_MOD_REP_MONTGOMERY ) );

    /* Neg( A == 0 ) => Zero result */
    mbedtls_mpi_mod_raw_neg( R, Z, &m );
    ASSERT_COMPARE( R, bytes, Z, bytes );

    /* Neg( A == N ) => Zero result */
    mbedtls_mpi_mod_raw_neg( R, N, &m );
    ASSERT_COMPARE( R, bytes, Z, bytes );

    /* Neg( A ) => Correct result */
    mbedtls_mpi_mod_raw_neg( R, A, &m );
    ASSERT_COMPARE( R, bytes, X, bytes );

    /* Neg( A ): alias A to R => Correct result */
    mbedtls_mpi_mod_raw_neg( A, A, &m );
    ASSERT_COMPARE( A, bytes, X, bytes );
exit:
    mbedtls_mpi_mod_modulus_free( &m );
    mbedtls_free( N );
    mbedtls_free( A );
    mbedtls_free( X );
    mbedtls_free( R );
    mbedtls_free( Z );
}
/* END_CASE */

/* END MERGE SLOT 7 */

/* BEGIN MERGE SLOT 8 */

/* END MERGE SLOT 8 */

/* BEGIN MERGE SLOT 9 */

/* END MERGE SLOT 9 */

/* BEGIN MERGE SLOT 10 */

/* END MERGE SLOT 10 */