diff --git a/library/ecp.c b/library/ecp.c
index 506f0cb..584e024 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -3059,32 +3059,32 @@
 
 #if defined(MBEDTLS_ECP_MONTGOMERY_ENABLED)
 MBEDTLS_STATIC_TESTABLE
-int mbedtls_ecp_gen_privkey_mx( size_t n_bits,
+int mbedtls_ecp_gen_privkey_mx( size_t high_bit,
                                 mbedtls_mpi *d,
                                 int (*f_rng)(void *, unsigned char *, size_t),
                                 void *p_rng )
 {
     int ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
     size_t b;
-    size_t n_bytes = ( n_bits + 7 ) / 8;
+    size_t n_bytes = ( high_bit + 7 ) / 8;
 
     /* [Curve25519] page 5 */
     do {
         MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( d, n_bytes, f_rng, p_rng ) );
     } while( mbedtls_mpi_bitlen( d ) == 0);
 
-    /* Make sure the most significant bit is n_bits */
-    b = mbedtls_mpi_bitlen( d ) - 1; /* mbedtls_mpi_bitlen is one-based */
-    if( b > n_bits )
-        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( d, b - n_bits ) );
+    /* Make sure the most significant bit is high_bit */
+    b = mbedtls_mpi_bitlen( d ) - 1; /* position of the highest bit in d */
+    if( b > high_bit )
+        MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( d, b - high_bit ) );
     else
-        MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, n_bits, 1 ) );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, high_bit, 1 ) );
 
     /* Make sure the last two bits are unset for Curve448, three bits for
        Curve25519 */
     MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 0, 0 ) );
     MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 1, 0 ) );
-    if( n_bits == 254 )
+    if( high_bit == 254 )
     {
         MBEDTLS_MPI_CHK( mbedtls_mpi_set_bit( d, 2, 0 ) );
     }