diff --git a/include/psa/crypto_struct.h b/include/psa/crypto_struct.h
index 01d3069..885d908 100644
--- a/include/psa/crypto_struct.h
+++ b/include/psa/crypto_struct.h
@@ -331,6 +331,13 @@
     return( attributes->policy.alg );
 }
 
+/* This function is declared in crypto_extra.h, which comes after this
+ * header file, but we need the function here, so repeat the declaration. */
+psa_status_t psa_set_key_domain_parameters(psa_key_attributes_t *attributes,
+                                           psa_key_type_t type,
+                                           const uint8_t *data,
+                                           size_t data_length);
+
 static inline void psa_set_key_type(psa_key_attributes_t *attributes,
                                     psa_key_type_t type)
 {