diff --git a/library/ecp.c b/library/ecp.c
index 91fbe3b9f..050a497e1 100644
--- a/library/ecp.c
+++ b/library/ecp.c
@@ -321,10 +321,10 @@ static int ecp_drbg_random( void *p_rng, unsigned char *output, size_t output_le
     ecp_drbg_context *ctx = p_rng;
     int ret;
     size_t len_done = 0;
+    uint8_t tmp[HASH_BLOCK_BYTES];
 
     while( len_done < output_len )
     {
-        uint8_t tmp[HASH_BLOCK_BYTES];
         uint8_t use_len;
 
         /* We don't need to draw more that 255 blocks, so don't bother with
@@ -346,6 +346,8 @@ static int ecp_drbg_random( void *p_rng, unsigned char *output, size_t output_le
         len_done += use_len;
     }
 
+    mbedtls_platform_zeroize( tmp, sizeof( tmp ) );
+
     return( 0 );
 }