diff --git a/ChangeLog b/ChangeLog
index 7ef0342bc..169474280 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -20,6 +20,13 @@ Bugfix
      program programs/x509/cert_write. Fixes #1422.
    * Ignore iv in mbedtls_cipher_set_iv() when the cipher mode is MBEDTLS_MODE_ECB
      Fix for #1091 raised by ezdevelop
+    * Fix failure in hmac_drbg in the benchmark sample application, when
+      MBEDTLS_THREADING_C is defined. Found by TrinityTonic, #1095
+    * Fix a bug in the update function for SSL ticket keys which previously
+      invalidated keys of a lifetime of less than a 1s. Fixes #1968.
+    * Zeroize memory used for reassembling handshake messages after use.
+    * Use `mbedtls_zeroize()` instead of `memset()` for zeroization of
+      sensitive data in the example programs aescrypt2 and crypt_and_hash.
 
 Changes
    * "make apidoc" now generates the documentation for the current
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 56567565b..4d3aa91a1 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3212,6 +3212,7 @@ static int ssl_reassemble_dtls_handshake( mbedtls_ssl_context *ssl )
 
     memcpy( ssl->in_msg, ssl->handshake->hs_msg, ssl->in_hslen );
 
+    mbedtls_zeroize( ssl->handshake->hs_msg, ssl->in_hslen );
     mbedtls_free( ssl->handshake->hs_msg );
     ssl->handshake->hs_msg = NULL;
 
diff --git a/programs/aes/aescrypt2.c b/programs/aes/aescrypt2.c
index de9d422cd..939c927a9 100644
--- a/programs/aes/aescrypt2.c
+++ b/programs/aes/aescrypt2.c
@@ -69,6 +69,12 @@ int main( void )
     return( 0 );
 }
 #else
+
+/* 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;
+}
+
 int main( int argc, char *argv[] )
 {
     int ret = 1;
@@ -441,13 +447,13 @@ exit:
        the case when the user has missed or reordered some,
        in which case the key might not be in argv[4]. */
     for( i = 0; i < argc; i++ )
-        memset( argv[i], 0, strlen( argv[i] ) );
+        mbedtls_zeroize( argv[i], strlen( argv[i] ) );
 
-    memset( IV,     0, sizeof( IV ) );
-    memset( key,    0, sizeof( key ) );
-    memset( tmp,    0, sizeof( tmp ) );
-    memset( buffer, 0, sizeof( buffer ) );
-    memset( digest, 0, sizeof( digest ) );
+    mbedtls_zeroize( IV,     sizeof( IV ) );
+    mbedtls_zeroize( key,    sizeof( key ) );
+    mbedtls_zeroize( tmp,    sizeof( tmp ) );
+    mbedtls_zeroize( buffer, sizeof( buffer ) );
+    mbedtls_zeroize( digest, sizeof( digest ) );
 
     mbedtls_aes_free( &aes_ctx );
     mbedtls_md_free( &sha_ctx );
diff --git a/programs/aes/crypt_and_hash.c b/programs/aes/crypt_and_hash.c
index 5885bdb5a..caad604a8 100644
--- a/programs/aes/crypt_and_hash.c
+++ b/programs/aes/crypt_and_hash.c
@@ -71,6 +71,12 @@ int main( void )
     return( 0 );
 }
 #else
+
+/* 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;
+}
+
 int main( int argc, char *argv[] )
 {
     int ret = 1, i, n;
@@ -533,13 +539,13 @@ exit:
        the case when the user has missed or reordered some,
        in which case the key might not be in argv[6]. */
     for( i = 0; i < argc; i++ )
-        memset( argv[i], 0, strlen( argv[i] ) );
+        mbedtls_zeroize( argv[i], strlen( argv[i] ) );
 
-    memset( IV,     0, sizeof( IV ) );
-    memset( key,    0, sizeof( key ) );
-    memset( buffer, 0, sizeof( buffer ) );
-    memset( output, 0, sizeof( output ) );
-    memset( digest, 0, sizeof( digest ) );
+    mbedtls_zeroize( IV,     sizeof( IV ) );
+    mbedtls_zeroize( key,    sizeof( key ) );
+    mbedtls_zeroize( buffer, sizeof( buffer ) );
+    mbedtls_zeroize( output, sizeof( output ) );
+    mbedtls_zeroize( digest, sizeof( digest ) );
 
     mbedtls_cipher_free( &cipher_ctx );
     mbedtls_md_free( &md_ctx );