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Implemented multiplication

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This commit is contained in:
Manuel Pégourié-Gonnard 2012-11-06 21:34:35 +01:00 committed by Paul Bakker
parent b4ab8a8137
commit efaa31e9ae
2 changed files with 142 additions and 14 deletions
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155
library/ecp.c
View File

@ -308,8 +308,66 @@ int ecp_add( const ecp_group *grp, ecp_point *R,
return ret;
}
/*
* Integer multiplication: R = m * P
* Using Montgomery's Ladder to avoid leaking information about m
*/
int ecp_mul( const ecp_group *grp, ecp_point *R,
const mpi *m, const ecp_point *P )
{
int ret = 0;
size_t pos;
ecp_point A, B;
ecp_point_init( &A ); ecp_point_init( &B );
/*
* The general method works only for m >= 2
*/
if( mpi_cmp_int( m, 0 ) == 0 ) {
ecp_set_zero( R );
goto cleanup;
}
if( mpi_cmp_int( m, 1 ) == 0 ) {
MPI_CHK( ecp_copy( R, P ) );
goto cleanup;
}
MPI_CHK( ecp_copy( &A, P ) );
MPI_CHK( ecp_add( grp, &B, P, P ) );
for( pos = mpi_msb( m ) - 2; ; pos-- )
{
if( mpi_get_bit( m, pos ) == 0 )
{
MPI_CHK( ecp_add( grp, &B, &A, &B ) );
MPI_CHK( ecp_add( grp, &A, &A, &A ) ) ;
}
else
{
MPI_CHK( ecp_add( grp, &A, &A, &B ) );
MPI_CHK( ecp_add( grp, &B, &B, &B ) ) ;
}
if( pos == 0 )
break;
}
MPI_CHK( ecp_copy( R, &A ) );
cleanup:
ecp_point_free( &A ); ecp_point_free( &B );
return( ret );
}
#if defined(POLARSSL_SELF_TEST)
#include "polarssl/error.h"
/*
* Return true iff P and Q are the same point
*/
@ -333,6 +391,8 @@ static void ecp_point_print( const ecp_point *P )
printf( "(%lu, %lu)\n", P->X.p[0], P->Y.p[0] );
}
#define TEST_GROUP_ORDER 13
/*
* Checkup routine
*
@ -348,27 +408,50 @@ int ecp_self_test( int verbose )
ecp_point O, A, B, C, D, E, F, G, H, TMP;
ecp_point *add_tbl[][3] =
{
{&O, &O, &O}, {&O, &A, &A}, {&A, &O, &A},
{&A, &A, &O}, {&B, &C, &O}, {&C, &B, &O},
{&A, &D, &E}, {&D, &A, &E},
{&B, &D, &F}, {&D, &B, &F},
{&D, &D, &G}, {&B, &B, &H},
{ &O, &O, &O }, { &O, &A, &A }, { &A, &O, &A },
{ &A, &A, &O }, { &B, &C, &O }, { &C, &B, &O },
{ &A, &D, &E }, { &D, &A, &E },
{ &B, &D, &F }, { &D, &B, &F },
{ &D, &D, &G }, { &B, &B, &H },
};
mpi m;
ecp_point mul_tbl[TEST_GROUP_ORDER + 1];
char *mul_tbl_s[TEST_GROUP_ORDER - 1][2] =
{
{ "17", "42" },
{ "20", "01" },
{ "14", "11" },
{ "34", "33" },
{ "21", "32" },
{ "27", "30" },
{ "27", "17" },
{ "21", "15" },
{ "34", "14" },
{ "14", "36" },
{ "20", "46" },
{ "17", "05" },
};
ecp_group_init( &grp );
ecp_point_init( &O ); ecp_point_init( &A ); ecp_point_init( &B );
ecp_point_init( &C ); ecp_point_init( &D ); ecp_point_init( &E );
ecp_point_init( &F ); ecp_point_init( &G ); ecp_point_init( &H );
ecp_point_init( &TMP );
mpi_init( &m );
for( i = 0; i <= TEST_GROUP_ORDER; i++ )
ecp_point_init( &mul_tbl[i] );
ecp_set_zero( &O );
MPI_CHK( ecp_group_read_string( &grp, 10, "47", "4", "17", "42", "13" ) );
MPI_CHK( ecp_point_read_string( &A, 10, "13", "0" ) );
MPI_CHK( ecp_point_read_string( &A, 10, "13", "00" ) );
MPI_CHK( ecp_point_read_string( &B, 10, "14", "11" ) );
MPI_CHK( ecp_point_read_string( &C, 10, "14", "36" ) );
MPI_CHK( ecp_point_read_string( &D, 10, "37", "31" ) );
MPI_CHK( ecp_point_read_string( &E, 10, "34", "14" ) );
MPI_CHK( ecp_point_read_string( &F, 10, "45", "7" ) );
MPI_CHK( ecp_point_read_string( &F, 10, "45", "07" ) );
MPI_CHK( ecp_point_read_string( &G, 10, "21", "32" ) );
MPI_CHK( ecp_point_read_string( &H, 10, "27", "30" ) );
@ -382,7 +465,7 @@ int ecp_self_test( int verbose )
{
if( verbose != 0 )
{
printf(" failed (%u)\n", i );
printf( " failed (%u)\n", i );
printf( " GOT: " );
ecp_point_print( &TMP );
printf( " EXPECTED: " );
@ -396,16 +479,60 @@ int ecp_self_test( int verbose )
if (verbose != 0 )
printf( "passed\n" );
MPI_CHK( ecp_copy( &mul_tbl[0], &O ) );
for( i = 1; i <= TEST_GROUP_ORDER - 1; i++ )
MPI_CHK( ecp_point_read_string( &mul_tbl[i], 10,
mul_tbl_s[i-1][0], mul_tbl_s[i-1][1] ) );
MPI_CHK( ecp_copy( &mul_tbl[TEST_GROUP_ORDER], &O ) );
if( verbose != 0 )
printf( " ECP test #2 (ecp_mul): " );
for( i = 0; i <= TEST_GROUP_ORDER; i++ )
{
MPI_CHK( mpi_lset( &m, i ) );
MPI_CHK( ecp_mul( &grp, &TMP, &m, &grp.G ) );
if( ! ecp_point_eq( &TMP, &mul_tbl[i] ) )
{
if( verbose != 0 )
{
printf( " failed (%u)\n", i );
printf( " GOT: " );
ecp_point_print( &TMP );
printf( " EXPECTED: " );
ecp_point_print( &mul_tbl[i] );
}
return( 1 );
}
}
if (verbose != 0 )
printf( "passed\n" );
cleanup:
if( ret != 0 && verbose != 0 )
printf( "Unexpected error, return code = %08X\n", ret );
{
#if defined(POLARSSL_ERROR_C)
char error_buf[200];
error_strerror( ret, error_buf, 200 );
printf( "Unexpected error: %d - %s\n\n", ret, error_buf );
#else
printf( "Unexpected error: %08X\n", ret );
#endif
}
ecp_group_free( &grp );
ecp_point_free( &O ); ecp_point_free( &A ); ecp_point_free( &B );
ecp_point_free( &C ); ecp_point_free( &D ); ecp_point_free( &E );
ecp_point_free( &F ); ecp_point_free( &G ); ecp_point_free( &H );
ecp_point_free( &TMP );
ecp_group_free( &grp ); ecp_point_free( &O ); ecp_point_free( &TMP );
ecp_point_free( &A ); ecp_point_free( &B ); ecp_point_free( &C );
ecp_point_free( &D ); ecp_point_free( &E ); ecp_point_free( &F );
ecp_point_free( &G ); ecp_point_free( &H );
mpi_free( &m );
for( i = 0; i <= TEST_GROUP_ORDER; i++ )
ecp_point_free( &mul_tbl[i] );
if( verbose != 0 )
printf( "\n" );

1
programs/test/selftest.c
View File

@ -50,6 +50,7 @@
#include "polarssl/x509.h"
#include "polarssl/xtea.h"
#include "polarssl/pbkdf2.h"
#include "polarssl/ecp.h"
int main( int argc, char *argv[] )
{