diff --git a/tf-psa-crypto/scripts/config.py b/tf-psa-crypto/scripts/config.py
index a5253b4..8412637 100755
--- a/tf-psa-crypto/scripts/config.py
+++ b/tf-psa-crypto/scripts/config.py
@@ -11,6 +11,7 @@
 ## SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
 ##
 
+import re
 import os
 import sys
 
@@ -18,6 +19,8 @@
 from mbedtls_framework import config_common
 
 
+PSA_SYMBOL_REGEXP = re.compile(r'^PSA_.*')
+
 PSA_UNSUPPORTED_FEATURE = frozenset([
     'PSA_WANT_ALG_CBC_MAC',
     'PSA_WANT_ALG_XTS',
@@ -93,7 +96,7 @@
     this might change to mean disabling them. Currently we just never set
     them to 0.)
     """
-    if name.startswith('PSA_WANT_'):
+    if re.match(PSA_SYMBOL_REGEXP, name):
         return True
     if not value:
         return True
@@ -179,7 +182,7 @@
             self._get_configfile().templates.append((name, '', f'#define {name} '))
 
         # Default value for PSA macros is '1'
-        if name.startswith('PSA_') and not value:
+        if not value and re.match(PSA_SYMBOL_REGEXP, name):
             value = '1'
 
         super().set(name, value)