diff --git a/ChangeLog b/ChangeLog
index df9e1a7da..96fca0226 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -25,6 +25,13 @@ Security
      being leaked to memory after release.
    * Fix dhm_check_range() failing to detect trivial subgroups and potentially
      leaking 1 bit of the private key. Reported by prashantkspatil.
+   * Make mbedtls_mpi_read_binary constant-time with respect to
+     the input data. Previously, trailing zero bytes were detected
+     and omitted for the sake of saving memory, but potentially
+     leading to slight timing differences.
+     Reported by Marco Macchetti, Kudelski Group.
+   * Wipe stack buffer temporarily holding EC private exponent
+     after keypair generation.
 
 Features
    * Allow comments in test data files.
diff --git a/include/mbedtls/bignum.h b/include/mbedtls/bignum.h
index 456a80420..214e83c2d 100644
--- a/include/mbedtls/bignum.h
+++ b/include/mbedtls/bignum.h
@@ -683,6 +683,10 @@ int mbedtls_mpi_exp_mod( mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi
  *
  * \return         0 if successful,
  *                 MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
+ *
+ * \note           The bytes obtained from the PRNG are interpreted
+ *                 as a big-endian representation of an MPI; this can
+ *                 be relevant in applications like deterministic ECDSA.
  */
 int mbedtls_mpi_fill_random( mbedtls_mpi *X, size_t size,
                      int (*f_rng)(void *, unsigned char *, size_t),
diff --git a/library/bignum.c b/library/bignum.c
index bd8280b6f..d27c130bc 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -63,6 +63,7 @@ static void mbedtls_mpi_zeroize( mbedtls_mpi_uint *v, size_t n ) {
     volatile mbedtls_mpi_uint *p = v; while( n-- ) *p++ = 0;
 }
 
+/* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = v; while( n-- ) *p++ = 0;
 }
@@ -676,16 +677,20 @@ cleanup:
 int mbedtls_mpi_read_binary( mbedtls_mpi *X, const unsigned char *buf, size_t buflen )
 {
     int ret;
-    size_t i, j, n;
+    size_t i, j;
+    size_t const limbs = CHARS_TO_LIMBS( buflen );
 
-    for( n = 0; n < buflen; n++ )
-        if( buf[n] != 0 )
-            break;
+    /* Ensure that target MPI has exactly the necessary number of limbs */
+    if( X->n != limbs )
+    {
+        mbedtls_mpi_free( X );
+        mbedtls_mpi_init( X );
+        MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, limbs ) );
+    }
 
-    MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, CHARS_TO_LIMBS( buflen - n ) ) );
     MBEDTLS_MPI_CHK( mbedtls_mpi_lset( X, 0 ) );
 
-    for( i = buflen, j = 0; i > n; i--, j++ )
+    for( i = buflen, j = 0; i > 0; i--, j++ )
         X->p[j / ciL] |= ((mbedtls_mpi_uint) buf[i - 1]) << ((j % ciL) << 3);
 
 cleanup:
@@ -1887,7 +1892,6 @@ int mbedtls_mpi_fill_random( mbedtls_mpi *X, size_t size,
 
 cleanup:
     mbedtls_zeroize( buf, sizeof( buf ) );
-
     return( ret );
 }
 
diff --git a/library/ecp.c b/library/ecp.c
index 5ad686398..b41baef27 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -1953,7 +1953,6 @@ int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
     {
         /* SEC1 3.2.1: Generate d such that 1 <= n < N */
         int count = 0;
-        unsigned char rnd[MBEDTLS_ECP_MAX_BYTES];
 
         /*
          * Match the procedure given in RFC 6979 (deterministic ECDSA):
@@ -1964,8 +1963,7 @@ int mbedtls_ecp_gen_keypair_base( mbedtls_ecp_group *grp,
          */
         do
         {
-            MBEDTLS_MPI_CHK( f_rng( p_rng, rnd, n_size ) );
-            MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( d, rnd, n_size ) );
+            MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( d, n_size, f_rng, p_rng ) );
             MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( d, 8 * n_size - grp->nbits ) );
 
             /*