- Make A only smaller if it is larger than |X| - 1

2011-01-05 15:53:06 +00:00 · 2011-01-05 15:53:06 +00:00 · b94081bfc1
commit b94081bfc1
parent ccba9bc42d
1 changed files with 5 additions and 2 deletions
--- a/library/bignum.c
+++ b/library/bignum.c
@ -1746,8 +1746,11 @@ int mpi_is_prime( mpi *X, int (*f_rng)(void *), void *p_rng )
        for( j = 0; j < A.n * ciL; j++ )
            *p++ = (unsigned char) f_rng( p_rng );

-        j = mpi_msb( &A ) - mpi_msb( &W );
-        MPI_CHK( mpi_shift_r( &A, j + 1 ) );
+        if( mpi_cmp_mpi( &A, &W ) >= 0 )
+        {
+            j = mpi_msb( &A ) - mpi_msb( &W );
+            MPI_CHK( mpi_shift_r( &A, j + 1 ) );
+        }
        A.p[0] |= 3;

        /*