diff --git a/tests/include/test/psa_crypto_helpers.h b/tests/include/test/psa_crypto_helpers.h
index c0f76c8..a280331 100644
--- a/tests/include/test/psa_crypto_helpers.h
+++ b/tests/include/test/psa_crypto_helpers.h
@@ -241,7 +241,9 @@
 int mbedtls_test_inject_entropy_restore(void);
 #endif /* MBEDTLS_PSA_INJECT_ENTROPY */
 
-
+/** Parse binary string and convert it to a long integer
+ */
+uint64_t parse_binary_string(data_t *bin_string);
 
 /** Skip a test case if the given key is a 192 bits AES key and the AES
  *  implementation is at least partially provided by an accelerator or
diff --git a/tests/include/test/psa_exercise_key.h b/tests/include/test/psa_exercise_key.h
index b5e3d35..46f4d08 100644
--- a/tests/include/test/psa_exercise_key.h
+++ b/tests/include/test/psa_exercise_key.h
@@ -119,6 +119,7 @@
  * The inputs \p input1 and \p input2 are, in order:
  * - HKDF: salt, info.
  * - TKS 1.2 PRF, TLS 1.2 PSK-to-MS: seed, label.
+ * - PBKDF2: input cost, salt.
  *
  * \param operation         The operation object to use.
  *                          It must be in the initialized state.