diff --git a/library/ecp.c b/library/ecp.c index bf570fe16..db69e42c0 100644 --- a/library/ecp.c +++ b/library/ecp.c @@ -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" ); diff --git a/programs/test/selftest.c b/programs/test/selftest.c index 98cc90ca3..333e3a16d 100644 --- a/programs/test/selftest.c +++ b/programs/test/selftest.c @@ -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[] ) {