diff --git a/library/pkcs5.c b/library/pkcs5.c
index 8a80aa5..1533a92 100644
--- a/library/pkcs5.c
+++ b/library/pkcs5.c
@@ -79,6 +79,11 @@
 #define mbedtls_printf printf
 #endif
 
+/* Implementation that should never be optimized out by the compiler */
+static void mbedtls_zeroize( void *v, size_t n ) {
+    volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;
+}
+
 #if defined(MBEDTLS_ASN1_PARSE_C)
 static int pkcs5_parse_pbkdf2_params( const mbedtls_asn1_buf *params,
                                       mbedtls_asn1_buf *salt, int *iterations,
@@ -312,6 +317,10 @@
                 break;
     }
 
+    /* Zeroise buffers to clear sensitive data from memory. */
+    mbedtls_zeroize( work, MBEDTLS_MD_MAX_SIZE );
+    mbedtls_zeroize( md1, MBEDTLS_MD_MAX_SIZE );
+
     return( 0 );
 }