diff --git a/mbedtls/src/hash/mod.rs b/mbedtls/src/hash/mod.rs
index c9799b155..d6a479357 100644
--- a/mbedtls/src/hash/mod.rs
+++ b/mbedtls/src/hash/mod.rs
@@ -126,6 +126,7 @@ impl Md {
     }
 }
 
+#[derive(Clone)]
 pub struct Hmac {
     ctx: Md,
 }