Implemented multiplication
diff --git a/library/ecp.c b/library/ecp.c
index bf570fe..db69e42 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -308,8 +308,66 @@
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 @@
printf( "(%lu, %lu)\n", P->X.p[0], P->Y.p[0] );
}
+#define TEST_GROUP_ORDER 13
+
/*
* Checkup routine
*
@@ -348,27 +408,50 @@
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 @@
{
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 @@
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" );